The structures of the six hydrogen-bonded 1:1 compounds of 4-methylquinoline with 2-chloro-4-nitrobenzoic acid, 2-chloro-5-nitrobenzoic acid, 2-chloro-6-nitrobenzoic acid, 3-chloro-2-nitrobenzoic acid, 4-chloro-2-nitrobenzoic acid and 5-chloro-2-nitrobenzoic acid have been determined at 185–190 K. In each crystal, the acid and base molecules are linked by a short hydrogen bond between a carboxy/carboxylate O atom and an N atom of the base. 10H9N) with chloro- and nitro-substituted benzoic acids (C7H4ClNO4), namely, 4-methylquinolinium 2-chloro-4-nitrobenzoate, C10H10N+·C7H3ClNO4−, (I), 4-methylquinoline–2-chloro-5-nitrobenzoic acid (1/1), C10H9N·C7H4ClNO4, (II), 4-methylquinolinium 2-chloro-6-nitrobenzoate, C10H9.63N0.63+·C7H3.37ClNO40.63−, (III), 4-methylquinolinium 3-chloro-2-nitrobenzoate, C10H9.54N0.54+·C7H3.46ClNO40.54−, (IV), 4-methylquinolinium 4-chloro-2-nitrobenzoate, C10H10N+·C7H3ClNO4−, (V), and 4-methylquinolinium 5-chloro-2-nitrobenzoate, C10H10N+·C7H3ClNO4−, have been determined at 185–190 K. In each compound, the acid and base molecules are linked by a short hydrogen bond between a carboxy (or carboxylate) O atom and an N atom of the base. The O⋯N distances are 2.5652 (14), 2.556 (3), 2.5485 (13), 2.5364 (13), 2.5568 (13) and 2.5252 (11) Å, respectively, for compounds (I)–(VI). In the hydrogen-bonded acid–base units of (III) and (IV), the H atoms are each disordered over two positions with O site:N site occupancies of 0.37 (3):0.63 (3) and 0.46 (3):0.54 (4), respectively, for (III) and (IV). The H atoms in the hydrogen-bonded units of (I), (V) and (VI) are located at the N-atom site, while the H atom in (II) is located at the O-atom site. In all the crystals of (I)–(VI), π–π stacking interactions between the quinoline ring systems and C—H⋯O hydrogen bonds are observed. Similar layer structures are constructed in (IV)–(VI) through these interactions together with π–π interactions between the benzene rings of the adjacent acid molecules. A short Cl⋯Cl contact and an N—O⋯π interaction are present in (I), while a C—H⋯Cl hydrogen bond and a π–π interaction between the benzene ring of the acid molecule and the quinoline ring system in (II), and a C—H⋯π interaction in (III) are observed. Hirshfeld surfaces for the title compounds mapped over dnorm and shape index were generated to visualize the weak intermolecular interactions.The structures of the six hydrogen-bonded 1:1 compounds of 4-methylquinoline (C Ka values of the acids and bases as well as the intermolecular interactions in the crystals. In our ongoing studies of crystal structures for the system of quinoline derivatives–chloro- and nitro-substituted benzoic acids, we have shown that three compounds of quinoline with 3-chloro-2-nitrobenzoic acid, 4-chloro-2-nitrobenzoic acid and 5-chloro-2-nitrobenzoic acid  – pKa(acid)] values of these compounds are in the range 2.93–3.38. Although the pKa value of 4-methylquinoline is 5.66, which is slight larger than quinoline (pKa = 4.90) and 6-methylquinoline (pKa = 5.20), the system of 4-methylquinoline–chloro- and nitro-substituted benzoic acids is an attractive candidate for studying short hydrogen bonds and also weak intermolecular interactions. We report here crystal structures of six hydrogen-bonded compounds, namely, 4-methylquinolinium 2-chloro-4-nitrobenzoate, (I)Ka values are 3.62, 3.44, 4.04, 3.84, 3.69 and 3.80, respectively, for (I)–(VI) (Table 1The properties of hydrogen bonds formed between organic acids and organic bases depend on the p) Table 1.The molecular structures of compounds (I)–(VI) are shown in Fig. 1abKa value of each compound are also given in Table 1The dihedral angles made by the benzene C1–C6 ring, the carboxy/carboxylate O1/C7/O2 plane and the nitro O3/N1/O4 plane of the acid, and the quinoline N2/C8–C16 ring system of the base in each hydrogen-bonded acid-base unit of (I)–(VI) are summarized in Table 1In all the compounds of 3-chloro-2-nitrobenzoic acid and 4-chloro-2-nitrobenzoic acid, the nitro O3/N1/O4 group is approximately perpendicular to the benzene C1–C6 ring with dihedral angles of 74.4 (3)–88.54 (13)°, while in the 2-chloro-6-nitrobenzoic acid molecule of compound (III)Ka value is observed for each system of quinoline and 6-methylquinoline compounds, while for the title compounds (I)–(VI) this correlation is somewhat low.The correlation between the H-atom position in the short hydrogen bond and the ΔpCg2⋯Cg2, Cg2⋯Cg3 and Cg3⋯Cg3, are 3.4323 (7)–3.7751 (8), 3.5878 (7)–3.9304 (9) and 3.7719 (8)–3.9227 (9) Å, respectively, where Cg2 and Cg3 are the centroids of the N2/C8–C11/C16 and C11–C16 rings of the quinoline ring system, respectively. The base molecules in the crystals of (I)via these π–π interactions, while in (III)–(VI) inversion-related base molecules are alternately stacked in column-like structures. On the other hand, π–π interactions between the inversion-related acid molecules are only observed in crystals (IV)–(VI); the centroid-centroid distances, Cg1⋯Cg1, are 3.5702 (7)–3.8602 (6) Å, where Cg1 is the centroid of the C1–C6 ring. Detailed supramolecular features in the crystals formed through these π–π interactions combined with other weak intermolecular interactions are described below.In all the crystals of (I)–(VI), π–π interactions between the quinoline ring systems, related by an inversion centre to each other, are observed. The centroid–centroid distances between the quinoline ring systems, namely, via π–π interactions between the quinoline ring systems . The dimeric units are further linked via a C—H⋯O hydrogen bond  Å. Between the layers, an N—O⋯π interaction  Å; symmetry code: (v) −x + 1, −y + 1, −z + 2] and a C—H⋯O hydrogen bond on Fig. 2. The ribon Fig. 2 via anotvia C—H⋯O hydrogen bonds  x, y + 1, z; (vi) −x + 1, −y + 1, −z]. The acid–base units are linked via these π–π interactions, forming a ribbon structure along the b-axis direction on Fig. 4. The tapon Fig. 5.i, C13—H13⋯O2ii and C14—H14⋯Cg1ii; symmetry codes as in Table 4c-axis direction  −x, −y, −z + 1; (v) −x + 1, −y, −z + 1].In the crystal of (III)on Fig. 6. The basms Fig. 7, and thua-axis direction  −x + 1, −y, z + 1; (iv) −x, −y, −z + 1]. The ribbons are further linked into a layer parallel to the (011) plane  of 3.6685 (8) Å . The layers are linked by a C—H⋯O hydrogen bond on Fig. 8 via C—H⋯ne Fig. 9 via a π–a-axis direction , 3.7751 (8), 3.7870 (8), 3.9304 (9) and 3.7719 (8) Å, respectively, for Cg1⋯Cg1vi, Cg2⋯Cg2iii, Cg2⋯Cg3ii, Cg2⋯Cg3iii and Cg3⋯Cg3ii . Between the layers, a C—H⋯O hydrogen bond is observed n Fig. 10 via a C—C2/c) is different from those of (IV)Pvia π–π interactions between the quinoline ring systems and C—H⋯O hydrogen bonds . The ribbons are connected into a layer parallel to (10via a weak π–π interaction between adjacent acid rings with Cg1⋯Cg1iv = 3.8602 (6) Å .Uiso(H) = 1.5Ueq(N or O); the refined distances are given in Tables 4Uiso(H) = 1.2 or 1.5Ueq(C).Crystal data, data collection and structure refinement details are summarized in Table 810.1107/S2056989021010896/hb7991sup1.cifCrystal structure: contains datablock(s) global, I, II, III, IV, V, VI. DOI: 10.1107/S2056989021010896/hb7991Isup2.hklStructure factors: contains datablock(s) I. DOI: Click here for additional data file.10.1107/S2056989021010896/hb7991Isup8.cmlSupporting information file. DOI: 10.1107/S2056989021010896/hb7991IIsup3.hklStructure factors: contains datablock(s) II. DOI: Click here for additional data file.10.1107/S2056989021010896/hb7991IIsup9.cmlSupporting information file. DOI: Click here for additional data file.10.1107/S2056989021010896/hb7991IIIsup10.cmlSupporting information file. DOI: 10.1107/S2056989021010896/hb7991IIIsup4.hklStructure factors: contains datablock(s) III. DOI: Click here for additional data file.10.1107/S2056989021010896/hb7991IVsup11.cmlSupporting information file. DOI: 10.1107/S2056989021010896/hb7991IVsup5.hklStructure factors: contains datablock(s) IV. DOI: Click here for additional data file.10.1107/S2056989021010896/hb7991Vsup12.cmlSupporting information file. DOI: 10.1107/S2056989021010896/hb7991Vsup6.hklStructure factors: contains datablock(s) V. DOI: Click here for additional data file.10.1107/S2056989021010896/hb7991VIsup13.cmlSupporting information file. DOI: 10.1107/S2056989021010896/hb7991VIsup7.hklStructure factors: contains datablock(s) VI. DOI: 2116680, 2116679, 2116678, 2116677, 2116676, 2116675CCDC references:  crystallographicinformation; 3D view; checkCIF reportAdditional supporting information:


Structures of three tetrahalophthalic anhydrides , Br (TBPA), I (TIPA)) were studied by X-ray diffraction, and several types of halogen bonds (HaB) and lone pair···π-hole (lp···πh) contacts were revealed in their structures. HaBs involving the central oxygen atom of anhydride group (further X···O(anhydride) were recognized in the structures of TCPA and TBPA. In contrast, for the O(anhydride) atom of TIPA, only interactions with the π system (π-hole) of the anhydride ring (further lp(O)···πh) were observed. Computational studies by a number of theoretical methods  demonstrated that the X···O(anhydride) contacts in TCPA and TBPA and lp(O)···πh in TIPA are caused by the packing effect. The supramolecular architecture of isostructural TCPA and TBPA was mainly affected by X···O(acyl) and X···X HaBs, and, for TIPA, the main contribution provided I···I HaBs. Charge transfer (CT) complexes are widely applied in different fields including sensors , ferroelIn the context of the discussion of noncovalent interactions, X···X  ,14,17,18Our experience in halogen bonding investigations ,21,22,23Literature structures of TXPA include one structure for TIPA: BOPDOZ, three for TCPA: TECLPA01-3, and five for TBPA: TBPHAN and TBPHAN01–4. TIPA and all TCPA structures were determined in the 1970s–80s and have poor quality by modern requirements. Because of this reason, we obtained a series of high-quality crystals of tetrahalophthalic anhydrides (including TBPA) and redetermined their structures (R ≤ 3%) using modern XRD equipment , C–X···O(anhydride), and C–X···X, where X is halogen atom  was carried out for each crystal with the aim to investigate the contribution of all intramolecular interactions in crystal packing (molecular surfaces are depicted in As it follows from Further contacts are considered in the order of their uniqueness and significance of the contribution to the supramolecular structure.RvdW [C–X···O(anhydride) interaction between the halogen atom (Cl2/Br2) and the anhydride oxygen atom (O1) is the distinctive feature of crystal packing of TCPA and TBPA. The distances C4–Cl2···O1 and C4–Br2···O1 (3.0972(14) Å and 3.1873(19) Å, respectively, RvdW ) ···πh bifurcate interaction between anhydride oxygen and two adjacent carbon atoms of a fused furan ring was found. The distances O1···C7 and O1···C8 were 3.057(4) Å and 3.127(4) Å, respectively, and the appropriate ΣH-carbazole (CCDC code VILFIF) and its N-methylated analogue (CCDC code WEXKEP) as well as the crystal of 2,3-dichloromaleic anhydride (CCDC code LIZCOM). The geometrical parameters of C–X···O(anhydride) interactions in these structures are presented in vdW radii, the conducted theoretical DFT calculations  short contacts: the co-crystals of pyromellitic dianhydride with 3,6-dibromo-9arene interaction was observed only for TIPA.Besides C–X···O(anhydride) contact in TCPA and TBPA, several types of HaB were observed in each crystal structure, which include HaB with acyl oxygen atom C–X···O=C and type II halogen–halogen contacts X···X. These interactions were presented in structures of all TXPA, whereas I···CRvdW . The angles ∠(C–X···O) varied in the range 173.08(7)–177.59(9)°, satisfying the IUPAC criteria for HaB [In the structures of TXPA each molecule forms a HaB with the acyl oxygen. The X···O(acyl) distances equaled 3.0373(16) Å, 3.093(2) Å, and 3.141(3) Å, respectively, which were shorter than the appropriate Σ for HaB . NoncovaRvdW = 3.50 Å); the distance Br1···Br2 was 3.5816(4) Å (vs. ΣRvdW was 3.70 Å). The angles ∠(C3–Cl1···Cl2) = 174.58(7)° and ∠(C1–Br1···Br2) = 173.89(8)° satisfied the criteria of HaB [In the crystals of TCPA and TBPA, there are two types of halogen atoms, and one behaves as an acceptor and one as a donor of X···X HaB. The contact Cl1···Cl2 is rather elongated (the interatomic distance was 3.4978(7) Å vs. Σa of HaB . The HaBa of HaB .RvdW (3.96 Å). The angles ∠(C4–I2···I1) = 174.00(8)° and ∠(C5–I3···I3) = 157.67(9)° are consistent with the IUPAC criteria for HaB [The arrangement of C–I···I bonds in TIPA is different from the noncovalent C–X···X bonding in the TCPA and TBPA structures described above. Each molecule of TIPA has two HaB donor iodine atoms, which form contacts C4–I2···I1 and C5–I3···I3. The distances (3.7497(6) Å and 3.7760(5) Å, respectively) were shorter than Σ for HaB . The I3 RvdW . In the case of TBPA, the distance of Br4···C2 was slightly longer than the ΣRvdW (3.584(3) Å vs. 3.55 Å).The from-the-atom lp(X)···πh interaction involving halogen atoms and a furan ring was observed in the TCPA and TBPA crystals . The disRvdW was 3.22 Å. Additionally, another acyl oxygen atom O3 in the TCPA molecule takes part in from-the-atom lp(O)···πh binding O3···C8 with the furan ring (the distance was 3.209(2) Å vs. ΣRvdW = 3.22 Å).In the cases of TCPA and TBPA, the acyl oxygen O2 forms from-the-bond lp(O)···πh bonding with C1 and C2 atoms of the fused five-membered ring. The distances O2···C1 and O2···C2 varied in the range of 2.939(3)–2.951(2) Å and 3.076(4)–3.043(3) Å for TCPA and TBPA, correspondingly, whereas the appropriate ΣContrastingly, in the TIPA crystal lp···πh interactions were realized only at the expense of the O1 atom of the furan ring as discussed above.The strength and nature of interactions were investigated for the most relevant contacts (C–X···O (acyl or anhydride) and C–X···X, where X is a halogen atom) by a number of theoretical methods: the molecular electrostatic potential (MEP) ,28, the The MEP surface is important to understand the nature of noncovalent interactions regulated by electrostatic effects ,28. On tb) and Laplacian (∇2ρb) and total energy density (Hb) at the BCP. Low values of ρb (0.008–0.010 a.u.), positive values f ∇2ρb (0.024–0.040 a.u.), and virtually zero values of Hb are typical for HaBs of weak strength [2)ρb (from −0.010 to −0.020 a.u.) indicates that these interactions between tetrahalophthalic anhydrides were attractive and that they fall into the van der Waals domain ρb(r) function mapped on the δginter isosurface and the 2D plot of the δginter descriptor against sign(λ2)ρb(r) are shown in The contacts in question were additionally examined and visualized by the independent gradient model method. The IGMH approach provides a quantitative reference for the characterization of noncovalent interactions, such as the fully noninteracting gradient reference |∇ρThe charge transfer (CT) is another important factor that may determine HaB. The second-order perturbation energy (E(2)) and the charge transfer value (∆occ) can be used to measure the intermolecular interactions . One canIn order to provide further insight into the electron density changes upon the formation of a halogen bond, electron density difference maps (EDD) for bimolecular fragments tetrahalophthalic anhydrides were calculated and the results are illustrated in Red regions represent the accumulation of electron density as a result of the formation of the complex, and blue regions indicate loss of electron density. The EDD plots also show that polarization effects caused by the positive σ-hole developed on the halogen atom tend to shift electron density from donor atoms and hence increase the electron density in the intermolecular space between halogen and oxygen atoms. The polarization of electron density between the halogen and donor atoms clearly implies the formation of the X···O/X interaction, which was also illustrated by the results of the NBO analysis .int) into its components , exchange (Eexch), induction (Eind), and dispersion (Edis) terms). Here, the SAPT0 level of theory was used to determine the Eint of the HaB bond in the bimolecular fragments in the X-ray structures  changed, which evidenced the critical role of packaging effects. Optimization of the TBPA fragment led to a contact switch from Br···O(anhydride) to two Br···O(carboxyl). The optimization of TIPAF1 led to a collapse of the structure, which was rearranged to the layered geometry. Thus, this interaction was dominated by the dispersion character over the electrostatic, which possibly led to the formation of a layered structure. Therefore, the O···C interactions between TIPA molecules were not sufficiently strong to be preserved in a gas phase.Finally, we investigated the dependence of X/C···O(anhydride) interactions on packing effects. To this aim, the full geometry optimization of the bimolecular fragments  was perf2Br2, and CH2I2 respectively.Tetrahlophthalic anhydrides are commercially available compounds and were purchased from Merck. Crystals of TCPA, TBPA, and TIPA suitable for X-ray studies were obtained via slow evaporation of solutions of the corresponding anhydrides in DMSO, CHwww.ccdc.cam.ac.uk/data_request/cif (accessed on 22 May 2021).X-ray diffraction studies were performed at 100 K on an Xcalibur Eos diffractometer (for TBPA and TIPA) using Mo-Kα (λ = 0.71073 nm) radiation and SuperNova diffractometer (for TCPA) using Cu-Kα (λ = 0.154184 nm) radiation. All structures were solved by direct methods by means of the SHELX program  incorporWave function calculations for the QTAIM, IGM, EDD, and NBO analyses were carried out using the crystallographic coordinate at the DFT PBE0 ,61 levelThe QTAIM, IGM, and EDD calculations were carried out using the Multiwfn 3.8 software ,71,72. TIn this work, we studied noncovalent interactions in the crystals of TXPA and recognized hitherto undescribed X···O(anhydride) short contacts in the structures of TCPA and TBPA. Based on the analysis of geometrical parameters, these contacts have been classified as HaBs. Contrastingly, in the crystal structure of TIPA, such HaB was not observed and anhydride oxygen was involved in the lp···πh interaction with C atoms of the anhydride system.int = −1.8 and −2.3 kcal/mol for TCPA and TBPA, respectively) and were apparently caused by packing effects. The structure of the TIPA crystal was predominantly directed by the strong I···I HaBs with a lesser role for the C–I···O(acyl) interaction , which provide another crystal packing profile and, hence, the absence of X···O(anhydride) contact. In addition, the performed calculations established that described X···O(anhydride) HaBs have an electrostatic and dispersive nature.Theoretical calculations demonstrated that the greater contribution to the architecture of TCPA and TBPA crystals were made by the C–X···O(acyl) and C–X···X HaBs, whereas X···O(anhydride) HaBs were weaker (EOn the one hand, these findings should be taken into account when using TXPA as CT acceptors because formation of close contacts may influence the CT complex structure. On the other hand, the ability of TXPA to form different types of non-covalent interactions can be useful for crystal engineering purposes and makes these species attractive as building blocks for the assembling of supramolecular constructions.


N-haloimides form two types of short (imide)X···N and X–X···N  halogen bonds. Nucleophilic substitution or ligand-exchange reaction on the peripheral X of X–X···N with the chloride of N-chlorosuccinimide lead to Cl–X···N halogen-bonded complexes. The 1:1 complexation of HMTA and ICl manifests the shortest I···N halogen bond [2.272(5) Å] yet reported for an HMTA acceptor. Two halogen-bonded organic frameworks are prepared using 1:4 molar ratio of HMTA and N-bromosuccinimide, each with a distinct channel shape, one possessing oval and the other square grid. The variations in channel shapes are due to tridentate and tetradentate (imide)Br···N coordination modes of HMTA. Density Functional Theory (DFT) studies are performed to gain insights into (imide)X···N interaction strengths (ΔEint). The calculated ΔEint values for (imide)Br···N  are smaller than the values for (imide)I···N . The DFT additivity analysis of (imide)Br···N motifs demonstrates Br···N interaction strength gradually decreasing from 1:1 to 1:3 HMTA:N-bromosuccinimide complexes. Exceptionally similar charge density values ρ(r) for N–I covalent bond and I···N non-covalent bond of a (saccharin)N–I···N motif signify the covalent character for I···N halogen bonding.Hexamethylenetetramine (HMTA) and  Non-aromatics, such as 1,4-diazabicylcooctane (DABCO) and hexamethylenetetramine (HMTA), have become a critical design trait in supramolecular chemistry, and have inspired scholars to devise molecular rotors  and 2.432(3) Å] are longer than in [DABCO]·[NBS]2 [2.347(2) and 2.364(2) Å] due to steric and competitive HB interactions in the former structure. (ii) Solvent as the only varying parameter, six different [HMTA]·[N-iodosuccinimide]4 XBOFs have been characterized using X-ray diffraction analysis  find the ″ideal″ HMTA:N-haloimide partner to access open-framework XBOF structures, and (iii) evaluate and compare the X···N interaction strengths.Our previous contributions in the field of HMTA halogen bonding include (i) the comparison of Br···N bond distances in bidentate complexes [HMTA]·[N-bromosuccinimide]1–13 of composition types [HMTA]·[dihalogen]n and [HMTA]·[N-haloimide]n  motifs, and complexes 2, 4, and 6 comprising hetero-halogen Y–X···N  motifs. The Br2 source in 1 and I2 in 3 and 5 are consequences of N–X bond cleavage reactions of NBS and NIS, respectively 2N–Br···N gradually converts to Br–Br···N motif by N–Br bond cleavage reaction followed by the exchange of (CO)2N and Br anions. In the second step, NCS, a chloride anion source, was added to replace the terminal bromide anion to give 2.HMTA and five different N-haloimides, namely N-chlorosuccinimide (NCS), N-bromosuccinimide (NBS), N-iodosuccinimide (NCS), N-bromophthalimide (NBP), and N-iodosaccharin (NISac), were used to prepare 13 halogen-bonded complexes oimide]n . [HMTA]· Filler, . The pre7–13 were obtained by slow evaporation of the corresponding HMTA and N-haloimide solutions . The 1:4 HMTA:NBS and 1:4 HMTA:NBP molar ratio reactions only gave the corresponding bidentate complexes 7 and 8 as the main products for structural analysis. Single-crystals isolated from different 1:4 HMTA:NBS experiments carried out by using various solvents also revealed the bidentate coordination for HMTA . Using a 1:4 HMTA:NBS molar ratio, complexes 9 and 10 were obtained employing different crystallization techniques. Complex 9, which contains a tridentate Br···N HMTA, was obtained using solvent-assisted grinding followed by solution crystallization, while 10, determined to be tetradentate Br···N HMTA, was crystallized by using the layering technique. Under the crystallization method of 9, the other HMTA-imide combinations produced crystals of either HMTA or corresponding imide. Even 9 is not reproducible and yields crystals of succinimide and bidentate complex 7. The lack of reproducibility is due to the influence of several uncontrolled factors in the crystallization process, such as N–X bond cleavage reactions and complex hydrogen bonding patterns.Single-crystals of 11. A 1:2 HMTA:NISac molar ratio gives a monodentate complex 12. However, treating HMTA with an excess of NISac (12.5 eq) leads to the formation of unknown quantities of iodine-oriented ions consequently resulting in an iodonium complex [bis(HMTA)I]+13. A related method to prepare [bis(HMTA)I]+2 and [HMTA]·[Ditfb]2, respectively. The corresponding XB parameters are used for discussions here and their structural data is included in the Supporting Information.Experiments conducted using 1:4 molar ratio of HMTA and NIS in different solvents all exclusively produced crystals of 1–13 illustrate four types of coordination modes. All the X···N  distances are below the sum of the Van der Waals radii of respective halogen  and nitrogen (1.55 Å)  are shown in HMTA in complexes ) Bondi, . Selecte1 and bidentate in 2 (3-center-4-electron [N–Br–N]+ XBs [2.086(5)−2.1862(4) Å] −2.1572(2) Å]  Å] is remarkably short compared to I–I···N distance of 3 [2.405(5) Å] indicating better e-accepting power of ICl. The monodentate Cl–I···N distance is shorter than +I–N halogen bonds reported for [bis(HMTA)I]++ XBs [2.198(3)−2.349(18) Å]. In the packing structure, 3 associates via HMTAN–I–I···NHMTA halogen bonds at distances of 3.519 Å forming zigzag 1D chains  Å], 5 [2.480(4) Å], and [HMTA]·[I–I]3 [2.593(6) Å]  and 2.426(4) Å] are slightly shorter than our previously reported solvent-free bidentate [HMTA]·[NBS]2 [2.414(3) and 2.432(3) Å]  Å, HMTA is bidentate in molecule . The two9 prepared by solvent-assisted manual grinding, contains four crystallographically independent NBS donors of which one NBS does not participate in the X-bonding. Three Br···N distances vary from 2.371(8) to 2.411(9) Å (3/unit cell. The relative channel volume (rcv)  Å . The fouolecules , which a11 contains bidentate HMTA, and the I···N distances   Å, 2 [2.879(5) and 2.864(4) Å]  distances of [DMAP]·[NIS]. However, both the (imide)N–I [2.26(2) Å] and I···N(HMTA) distances [2.29(2) Å] of 12 are remarkably close to [DMAP]·[NISac] [2.292(2) and 2.218(2) Å]  and 2.299(15) Å, and appear within 0.02 Å of the corresponding distances in the reported structure (Complex 18(2) Å] . Complextructure .S, min, −30 kcal/mol), is comparable to values estimated at the O-atoms of NBS  and NBP . A VS, max of magnitude +16 kcal/mol is associated with the –CH2- protons adjacent to the sp3 N-atom. In NBS, the VS, max at the bromine σ-hole and the five-member ring-centroid are similar  is slightly smaller than in NBS but larger than in NBP. To our surprise, the electron-withdrawing –SO2 group of NISac could only render a positive potential of +7 kcal/mol at the six-membered ring-centroid. The global MEP analysis suggests that the nucleophilic and electrophilic sites of HMTA and NBS/NIS molecules have equal propensity to form Br···N, C–H···N, and C–H···O=C interactions, which is in good agreement with packing forces discussed in the XBOF structures X···N motif in a 1:1 complex when donors are successively added to HMTA, are estimated for complexes [HTMA]·[NBS]int) were estimated by using their corresponding X-ray crystal structure coordinates. The calculated ΔEint values range from −11.2 to −12.5 kcal/mol for Br···N motifs. The ΔEint values decrease when the HMTA denticity increases, −12.5 kcal/mol for 7, −12.1 kcal/mol for 9, and −11.2 kcal/mol for 10, and the results are in good agreement with the additivity analysis. The ΔEint value of 7 is stronger than NBS···NPy   for N–Br covalent bond and Br···N non-covalent bond are significantly different, indicating the absence of a shared-shell character  are slightly larger than in 7 . This agrees with the well-known fact that the fused six-membered ring in NBP removes electron density from the five-membered ring, consequently making the bromine more electrophilic. The ΔEint values of ancillary interactions, for example, N···π(ring-centroid) and C–H···N hydrogen bond contacts in 7, are estimated to understand their interaction strengths relative to Br···N motifs  and C–H···N  contacts are weaker than XBs . The presence of the BCPs and bond paths of their connecting atoms are other evidences for N···π and C–H···N contacts. This suggests that weak and moderately strong HBs, that originate from donor-acceptor components' electron-rich and deficient sites, are inevitable and may contribute to the XB stabilization energy.In contrast to the same σ-hole strengths of NBS and NBP, the Br···N halogen bonds interaction strengths of tifs see . The ΔEi11  and [HMTA]·[NIS]4  are larger than corresponding bromine structures, and twice the energy of C–I···N contacts  in [HMTA]·[Iodopentafluorobenzene]2 (see int and the ρ(r) values at the BCP of 11 are somewhat larger than [HMTA]·[NIS]4, which agrees with the additivity analysis. Complex 12 involving NISac has the largest interaction energy of all the (imide)I···NHMTA halogen bonds  owing to larger iodine σ-hole strength in NISac . The ρ(r) values at the BCPs of I···N halogen bond, similar to N–I covalent indicating a degree of covalency with shared-shell character, is remarkable. This agrees with the N–I and I···N bonds covalent character discussion in [DMAP]·[NISac]  and are comparable to HB energies observed in 7. The AIM analysis reveals that C–H···O=S and C–H···π interactions may contribute to the formation of I···NHMTA interactions.The I···N interaction energies of ne]2 see . The ΔEiN-iodosaccharin even approaches the reported 3-center-4-electron halogen bonds of [(HMTA)N–I–N(HMTA)]+ [2.288(14) and 2.299(15) Å]. The scope of halogen-bonded organic frameworks (XBOFs), previously accessed by (imide)I···N using a 1:4 [HMTA]:[NIS] building block, is expanded to (imide)Br···N halogen-bonded 1:3 [HMTA]:[NBS] and 1:4 [HMTA]:[NBS] structures. Different from (imide)I···N XBOFs, channel shape adaptability is achieved through HMTA tridentate and tetradentate coordination modes. DFT based MEPs provided us with important experimental insights into the nature of donor-donor and donor-acceptor interactions. Donors, such as NBS/NIS possessing σ-hole  and C–H acidic proton  values, have high probabilities to form XBOFs via (imide) X···N halogen bonds and orthogonal C–H···O=C hydrogen bonds. The lack of acidic sp3 C–H protons, like in NBP, encourage π-π and other hydrogen bond interactions obstructing the formation of the desired 1:4 ratio [HMTA]:[NBP] and eventually affect XBOFs' self-assembly processes. In terms of DFT interactions energies, the (imide)N–X···N(HMTA) halogen bonds varying from −11.2 to −12.5 kcal/mol for X = Br, and −8.4 to −29.0 kcal/mol for X = I, are stronger than corresponding (imide)N–X···N(pyridines) halogen bonds. A comprehensive solution NMR study on [HMTA]·[N-haloimide]n complexes, optimization of crystallization conditions to synthesize XBOFs using other HMTA-imide combinations, and post-synthetic solvent exchange process of (imide)N–Br···N XBOFs are currently under investigation in our laboratory.In summary, we investigated Y–X···N  halogen bonds in 13 X-ray crystal structures obtained from HMTA and N-haloimides. Two complexes of HMTA with iodoperfluorobenzene and 1,4-diiodotetrafluorobenzene consisting of C–I···N halogen bonds were also prepared, and their solid-state structures were studied for comparison purposes. The Y–X···N distances depend on the nature of Y-atom and the donor scaffold. The Br/Cl–Br···N [2.088(3)−2.167(3) Å] are shorter than (imide)N–Br···N [2.371(8)−2.426(4) Å] halogen bonds. In contrast, the I/Cl–I···N [2.328(3)−2.486(5) Å] tend to be longer when compared to (imide)N–I···N [2.29(3) and 2.502(10) Å] halogen bonds. The shortest I···N [2.29(3) Å] distance between HMTA and The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found in the article/12, for X-ray crystallography, done in JYU, were prepared by GA, 12 was prepared by LG. Both JR and GP were external thesis supervisors for GA and LG, respectively. AF and AB were responsible for computational studies. KR was responsible for proofreading the final manuscript version. All authors have read and agreed to the published version of the manuscript.RP was responsible for supervision, methodology development, manuscript preparation, and SCXRD analysis. All halogen bond complexes, except The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


The molecular structure is stabilized by an O—H⋯N hydrogen bond, forming an S(6) ring motif.The title compound, C 22H18N2O2, is a Schiff base that exists in the phenol–imine tautomeric form and adopts an E configuration with respect to the C=N bond. The molecular structure is stabilized by an O—H⋯N hydrogen bond, forming an S(6) ring motif. In the crystal, pairs of C—H⋯O hydrogen bonds link the molecules to form inversion dimers. Weak π–π stacking interactions along the a-axis direction provide additional stabilization of the crystal structure. The molecule is non-planar, the aromatic ring of the benzaldehyde residue being nearly perpendicular to the phenyl and 4-methylphenol rings with dihedral angles of 88.78 (13) and 82.26 (14)°, respectively. A molecular docking study between the title molecule and the COVID-19 main protease (PDB ID: 6LU7) was performed, showing that it is a potential agent because of its affinity and ability to adhere to the active sites of the protein.The title compound, C We report here the synthesis, crystal and molecular structure of the title compound. We have also performed a molecular docking study to determine possible intermolecular interactions between the COVID-19 main protease (PDB ID: 6LU7) and the title compound.Schiff bases have wide applications interests as corrosion inhibitors  ring motif, which stabilizes the molecular structure. The dibenzylidene hydrazine unit is approximately planar with the dihedral angle formed by the two terminal phenyl rings of 7.62 (15)°. On the other hand, the molecule is non-planar, because the C1–C6 ring is nearly perpendicular to the C9–C14 and C16–C21 rings with dihedral angles of 88.78 (13) and 82.26 (14)°, respectively. The C17—O2, C15—N2 and C15—C16 bond lengths in the molecule are 1.359 (5), 1.287 (5), and 1.452 (5) Å, respectively. These results suggest single-bond character for C17—O2 and C15—C16 and double-bond character for the C15—N2 bond as expected for a phenol–imine structure  ring motif.The asymmetric unit of the title structure contains one molecule Fig. 1, which cCg2⋯Cg3 = 3.909 (2) Å; Cg2 and Cg3 are the centroids of the C9–C14 and C16–C21 rings, respectively] that stabilize the crystal structure, forming a three-dimensional network.In the crystal, molecules are linked by pairs of C3—H3⋯O2 hydrogen bonds, forming inversion dimers with an f Table 1. There aet al., 2016et al., 2011sp2—Csp2 single bond, is slightly longer than observed for the title compound [1.472 (5) Å]. This bond length is shorter than in NOTZIH hydrazineylidene}-1,2-diphenylethan-1-one was prepared by refluxing a mixture of a solution containing 2-hydroxy-5-methylbenzaldehyde (0.02 mmol) in ethanol (20 mL) and a solution containing (E)-2-hydrazineylidene-1,2-diphenylethan-1-one (0.02 mmol) in ethanol (20 mL). The reaction mixture was stirred for 5 h under reflux. The obtained crystalline material was washed with ethanol and dried at room temperature. Single crystals of the title compound for X-ray analysis were obtained by slow evaporation of an ethanol solution.(Uiso(H) = 1.5Ueq(O). The C-bound H atoms were positioned geometrically and refined using a riding model with C—H = 0.93 and Uiso(H) = 1.2Ueq(C) for aromatic H atoms, and with C—H = 0.96 Å and Uiso(H) = 1.5Ueq(C) for methyl H atoms.Crystal data, data collection and structure refinement details are summarized in Table 210.1107/S2056989021005442/yk2152sup1.cifCrystal structure: contains datablock(s) I. DOI: 10.1107/S2056989021005442/yk2152Isup2.hklStructure factors: contains datablock(s) I. DOI: Click here for additional data file.10.1107/S2056989021005442/yk2152Isup3.cmlSupporting information file. DOI: 2085577CCDC reference:  crystallographic information; 3D view; checkCIF reportAdditional supporting information:


N,N,N′,N′-tetramethylethanediamine, C6H16N2, crystallizes in the monoclinic crystal system in the space group P21/c. For the investigation of the conformation, quantum chemical methods were used and for intermolecular interactions, a Hirshfeld surface analysis was performed. N,N,N′,N′-tetramethylethanediamine, C6H16N2, is a bidentate amine ligand commonly used in organolithium chemistry for deaggregation. Crystals were grown at 243 K from n-pentane solution. The complete molecule is generated by a crystallographic center of symmetry and the conformation of the diamine is antiperiplanar. To investigate the intermolecular interactions, a Hirshfeld surface analysis was performed. It showed that H⋯H  interactions dominate with a contact percentage of 92.3%.The title compound  N,N,N′,N′-tetramethylethanediamine  consists of two tertiary amine groups linked by an ethylene bridge. It can be used in cross-coupling or in olefin polymerization reactions where, e.g., a complex between dimethylnickel and TMEDA is used as a catalyst  −x, 1 − y, 1 − z] = 180.0° by symmetry. The conformations of the C1—N1—C3—C3i and C2—N1—C3—C3i groupings are anti [torsion angle = 167.33 (6)°] and gauche [–71.17 (8)°], respectively.Compound et al., 2013Gaussian 16   -tris(tetramethylethylenediaminelithium)methylthorium(IV) tetramethylethylenediamine -({[(S)-2-(methoxymethyl)pyrrolidin-1-yl]methyl}dimethylsilyl)(phenyl)methyl]lithium N,N,N′,N′-tetramethylethanediamine  was purchased by Sigma-Aldrich and was used without further purification. A solution of TMEDA (0.5 mmol) in n-pentane (1 ml) was prepared at 243 K and 1 crystallized in the form of colorless blocks.Uiso(H) = 1.2Ueq(C) for CH2 and CH hydrogen atoms and Uiso(H) = 1.5Ueq(C) for CH3 hydrogen atoms.Crystal data, data collection and structure refinement details are summarized in Table 210.1107/S2056989021012457/hb8002sup1.cifCrystal structure: contains datablock(s) I. DOI: 10.1107/S2056989021012457/hb8002Isup2.hklStructure factors: contains datablock(s) I. DOI: Click here for additional data file.10.1107/S2056989021012457/hb8002Isup3.cmlSupporting information file. DOI: 2123810CCDC reference:  crystallographicinformation; 3D view; checkCIF reportAdditional supporting information:


III complex with a multidentate NSO-containing mixed-ligand − 2-hydroxy-3-methoxybenzaldehyde thiosemicarbazone – is reported.The synthesis, crystal structure and spectroscopic characterization of the novel and, according to our knowledge the first to be obtained in crystalline form, Co III complex, bis[biscobalt(III)] dithionate–dimethylformamide–methanol (1/4/3), [Co(C9H10N3O2S)2]2(S2O6)·4C3H7NO·3CH3OH, with monodeprotonated 2-hydroxy-3-methoxybenzaldehyde thiosemicarbazone as ligands crystallizes in the space group PL2]+ cations, one dithionate anion (S2O6)2− as counter-anion and seven solvate molecules (four dimethylmethanamide and three methanol). Each CoIII ion has a moderately distorted octahedral S2N2O2 geometry. In the crystal, the components are linked by numerous N—H⋯O and O—H⋯O contacts.The title Co Thus, the coordination geometry around each CoIII ion can be described as moderately distorted octahedral with an S2N2O2 coordination sphere with N,O,N and S atoms in the equatorial plane and O and S atoms in the apical positions.The title complex crystallizes in the triclinic space group it Fig. 1 consistset al., 2013II complexes with related semicarbazone ligands  to those in an analogous chromium complex with a similar ligand  approaches the standard C=S double-bond value and differs only slightly from the distance observed in the corresponding neutral ligand [1.688 Å in BIZYAL  and twisted, as defined by the dihedral angles of 83.42 (7)° between the mean planes of atoms O1/C1/C6/C8/N1/N2/C9/S1 and O3/C10/C15/C17/N4/N5/C18/S2 around Co1, and 86.3 (1)° between the mean planes of atoms O7/C28/C33/C35/N10/N11/C36/S4 and O5/C19/C24/C26/N10/N8/C27/S3 around Co2.The ligands coordinated to the CoThe solid-state organization of the complex can be described as an insertion of the anions and solvent molecules within the crystallographically independent complexes Fig. 2. In the A⋯O8, N2—H2⋯O3 and N2—H2⋯O4 are contacts between ligands through the nitrogen of the secondary amino group and methoxy group oxygen;N8—H8A⋯O11 and N12—H12B⋯O9 are contacts between the nitrogen of the secondary and primary  amino groups of the ligands and oxygen atoms of the S2O6 anions .N3—H32O6)2− anions act as a multiple-acceptor species for N,O donor atoms of neighboring complexes (by N—H⋯O interactions) and methanol solvent molecules (by O—H⋯O contacts). The oxygen atoms (O16) of the dimethylmethanamide molecules bridge adjacent cationic complexes  of the ligand in 1ml of dimethylformamide and 1ml of chloroform. Dark-brown crystals of the title compound, suitable for X-ray analysis, were formed within a few days (yield: 60%).The title compound was prepared according to a previously published procedure  due to aromatic =C—H stretching at 3000–3100 cm−1, the aromatic ring vibrations in the 1600–1400 cm−1 region, weak absorption band at 738 cm−1 due to υ(C—S) vibrations and the characteristic peak at 1608 cm−1 assigned to azomethine υ(C=N) group. The weak band at 3308 cm−1 can be assigned to the N—H group vibrations. All these data are in good agreement with literature data : C 38.19; N 14.33; H 5.16%. Found: C 38.21; N 14.40; H 5.21%.The IR spectrum of the title compound (as KBr pellets) is consistent with the above structural data. In the range 4000–400 cmII dithionate used in this work was prepared by mixing aqueous solutions containing stoichiometric amounts of cobalt sulfate and BaS2O6·2H2O. The white precipitate of BaSO4 was removed by filtration and the solution containing the metal dithionate was evaporated to a small volume on a rotary evaporator and then cooled for crystallization. BaS2O6·2H2O was prepared using the method described by Pfanstiel (1946The Cotiel 1946.Uiso(H) = 1.2Ueq(C) for aromatic CH and Uiso(H) = 1.5Ueq(C) for methyl groups. The H atoms of the NH and OH groups were also placed at calculated position using the corresponding AFIX instruction with Uiso(H) = 1.2Ueq(N) for NH/NH2 and Uiso(H) = 1.5Ueq(O) for OH hydrogen atoms.Crystal data, data collection and structure refinement details are summarized in Table 210.1107/S2056989021010616/tx2043sup1.cifCrystal structure: contains datablock(s) I. DOI: 10.1107/S2056989021010616/tx2043Isup2.hklStructure factors: contains datablock(s) I. DOI: 2115486CCDC reference:  crystallographicinformation; 3D view; checkCIF reportAdditional supporting information:


The title thiourea derivative adopts a U-shaped conformation, which incorporates an intramolecular amine-N—H⋯N(imine) hydrogen bond. In the molecular packing, supramolecular chains are formed through hydroxyl-O—H⋯S(thione) and amine-N—H⋯O hydrogen bonding. 17H19N3OS, adopts a U-shaped conformation with the dihedral angle between the terminal aromatic rings being 73.64 (5)°. The major twist in the molecule occurs about the ethane bond with the Ci—Ce—Ce—Cb torsion angle being −78.12 (18)°; i = imine, e = ethane and b = benzene. The configuration about the imine bond is E, the N-bound H atoms lie on opposite sides of the molecule and an intramolecular amine-N—H⋯N(imine) hydrogen bond is evident. In the molecular packing, hydroxyl-O—H⋯S(thione) and amine-N—H⋯O hydrogen bonding feature within a linear, supramolecular chain. The chains are connected into a layer in the ab plane by a combination of methylene-C—H⋯S(thione), methylene-C—H⋯O(hydroxyl), methyl-C—H⋯π(phenyl) and phenyl-C—H⋯π(hydroxybenzene) interactions. The layers stack without directional interactions between them. The analysis of the calculated Hirshfeld surface highlights the presence of weak methyl-C—H⋯O(hydroxyl) and H⋯H interactions in the inter-layer region. Computational chemistry indicates that dispersion energy is the major contributor to the overall stabilization of the molecular packing.The title thiourea derivative, C Globally, both aromatic residues lie to the same side of the molecule so that it has a U-shaped conformation.The molecular structure of (I)E. The N-bound H atoms lie to opposite sides of the molecule, a conformation that allows for the formation of an intramolecular amine-N—H⋯N(imine) hydrogen bond, Table 1The C1—S1 bond length is 1.6910 (15) Å, the C1—N1 bond [1.340 (2) Å] is marginally shorter than the C1—N2 [1.356 (2) Å] bond, the formally C8—N3 double bond is 1.284 (2) Å and N2—N3 is 1.3857 (18) Å. These values, coupled with the observed planarity in this region of the molecule, is suggestive of some delocalization of π-electron density over this residue. The configuration about the C8=N3 imine bond is a). They are connected into a supramolecular layer parallel to the c axis via methylene-C—H⋯S(thione) and methylene-C—H⋯O(hydroxyl) interactions as well as methyl-C—H⋯π(phenyl) and phenyl-C—H⋯π(hydroxybenzene) contacts, Table 1b). The layers thus formed are two molecules thick and stack along the c-axis direction without directional interactions between them, Fig. 2c). Finally, as indicated in Fig. 2b) and (c), the supramolecular connectivity brings two sulfur atoms into close proximity, with an S1⋯S1i separation of 3.3534 (6) Å, cf. the sum of the van der Waals radii of 3.60 Å , i.e. near the amine-H2N and thione-S1 atoms, correspond to the amine-N2—H2N⋯O1(hydroxyl), hydroxyl-O1—H1O⋯S1(thione) hydrogen bonds and the thione-S1⋯S1(thione) short contact; these and other short contacts calculated using Crystal Explorer 17 are collated in Table 2b), where the positive electrostatic potential (blue) and negative electrostatic potential (red) regions are observed around the amine-H2N and thione-S1 atoms, respectively. The faint red spots appearing near the thione-S1, hydroxyl-O1 and methylene-H11A and H11B atoms  and phenyl-C6—H6⋯π interactions are shown as faint red spots on the dnorm surface in Fig. 5a) and as two distinctive orange ‘potholes’ on the shape-index-mapped over Hirshfeld surface in Fig. 5b). It is noted that the phenyl-C4—H4⋯π interaction, Table 1dnorm-mapped Hirshfeld surface. However, this interaction clearly shows up as an orange ‘pothole’ on the shape-index-mapped Hirshfeld surface in Fig. 6The bright-red spots on the Hirshfeld surface mapped over ms Fig. 4 correspoa) and those delineated into H⋯H, H⋯C/C⋯H, H⋯S/S⋯H and H⋯O/O⋯H contacts are illustrated in Fig. 7b)–(e), respectively. The percentage contributions to the Hirshfeld surface of (I)de = di ∼2.1 Å, Fig. 7b), corresponds to the intra-layer H1O⋯H2N contact listed in Table 2c), reflecting the significant C—H⋯π interactions evinced in the packing analysis, Table 1de = di ≃ 2.2 Å in Fig. 7d) and (e), respectively. The contributions from the other six interatomic contacts summarized in Table 3The overall two-dimensional fingerprint plot computed for (I)Eele), polarization (Epol), dispersion (Edis) and exchange-repulsion (Erep) energy components  and Erep (12.2 kJ mol−1) terms and having a total energy of 11.7 kJ mol−1 is non-attractive.The energy frameworks were calculated for (I)Edis component. The greatest stabilization energy in the inter-layer region arises from methyl-C9—H9B⋯O1(hydroxyl)  and methylene-H10⋯H16(hydroxybenzene) interactions , which sum to −30.7 kJ mol−1. Generally, the long-range H⋯H contacts are the major interactions stabilizing the molecules within the inter-layer region.The stabilization energies in the inter-layer region are dominated by the a axis direction are shown in Fig. 8Eele of all pairwise interactions sum to −145.4 kJ mol−1, while the Edis totals −342.1 kJ mol−1.Views of the energy framework diagrams down the via an ethane link. Each of these is a N-methyl species, i.e. MeN(H)C(=S)N(H)N=C(Me)CH2CH2Ar, one with Ar = phenyl  torsion angle = −62.76 (16)°], a conformation stabilized, at least in part, by an intramolecular amine-N—H⋯π(phenyl) interaction. By contrast, in the species with Ar = 4-methoxybenzene, the molecule is close to planar as indicated by the Ci—Cm—Cm—Cp torsion angles of 177.51 (12) and −175.80 (12)°, respectively, for the two independent molecules comprising the asymmetric unit. Thus, to a first approximation, the conformation observed in (I)In the crystallographic literature, there are two precedents for molecules related to (I)in vacuo. Single crystals were grown at room temperature in mixed solvents of dimethyformamide and acetonitrile (1:2 v/v) by slow evaporation. 1H NMR : δ 9.14 , 8.59 , 7.59 , 7.37 , 7.22 , 7.03 , 6.76 , 5.46 , 2.83 , 2.61 , 1.90 . 13C NMR : δ 176.22, 154.16, 152.02, 137.93, 132.72, 129.39, 128.84, 126.16, 124.39, 115.57, 40.38, 31.58, 16.19.4-Phenyl-3-thiosemicarbazide (10 mmol) dissolved in hot absolute ethanol (50 ml) was combined with 4-(4-hydroxyphenyl)-2-butanone (10 mmol), dissolved in hot absolute ethanol (50 ml) with a few drops of concentrated hydrochloric acid added as catalyst. The mixture was heated (348 K) and stirred for about 30 min. The mixture was allowed to cool to room temperature while stirring. The white precipitate was filtered, washed with cold ethanol and dried Uiso(H) set to 1.2–1.5Ueq(C). The O-bound and N-bound H atoms were located in a difference-Fourier map but were refined with O—H = 0.84±0.01 and N—H = 0.88±0.01 Å distance restraints, respectively, and with Uiso(H) set to 1.5Ueq(O) and 1.2Ueq(N).Crystal data, data collection and structure refinement details are summarized in Table 510.1107/S2056989021006666/hb7978sup1.cifCrystal structure: contains datablock(s) I, global. DOI: 10.1107/S2056989021006666/hb7978Isup2.hklStructure factors: contains datablock(s) I. DOI: Click here for additional data file.10.1107/S2056989021006666/hb7978Isup3.cmlSupporting information file. DOI: 2092413CCDC reference:  crystallographic information; 3D view; checkCIF reportAdditional supporting information:


Further, cleavage of the [Fe‐S‐Fe] unit by CS2 is presented.A [Fe‐S‐Fe] subunit with a single sulfide bridging two low‐coordinate iron ions is the supposed active site of the iron‐molybdenum co‐factor (FeMoco) of nitrogenase. Here we report a dinuclear monosulfido bridged diiron(II) complex with a similar complex geometry that can be oxidized stepwise to diiron(II/III) and diiron(III/III) complexes while retaining the [Fe‐S‐Fe] core. The series of complexes has been characterized crystallographically, and electronic structures have been studied using, inter alia,  A dinuclear monosulfido bridged diiron(II) complex is reported that can be oxidized stepwise to diiron(II/III) and diiron(III/III) complexes while retaining the [Fe‐S‐Fe] core. This unprecedented series of low‐coordinate complexes has been thoroughly characterized using inter alia, 57Fe Mössbauer spectroscopy and SQUID magnetometry. The reaction takes place at the iron‐molybdenum co‐factor (FeMoco), which constitutes a ligated [MoFe7S9C] unit.Nitrogenase (N2+ complex with an unsupported monosulfide bridge via the reaction of a two‐coordinate iron(I) silylamide with elemental sulfur. Subsequent oxidation leads to the first example of a mixed valent [2Fe‐1S]3+ and an “all ferric” [2Fe‐1S]4+ form. The series of complexes was examined with respect to their spectroscopic and physical properties. The initial [2Fe‐1S]2+ complex was further subjected to a variety of small molecule substrates that are transformed by the N2‐ase, however showing only a limited reactivity or stability. Most notably, its reaction with CS2 led to rupture of the Fe‐S‐Fe motif and formation of a mononuclear iron(II) thiocarbonate complex, revealing the structural lability of the [Fe‐S‐Fe] unit.This unit is assumed to open up during substrate turnover, as experimentally shown by displacement of the sulfide unit by CO or selenide.2, 6 A2] (L=‐N(Dipp)SiMe3, Dipp=2,6‐diisopropylphenyl), 1,2O with 1/16 S8 for 16 h led to the formation of a colorless solid. X‐Ray diffraction analysis of suitable single crystals showed the formation of the dinuclear complex (K{18c6})2[(FeL2)2(μ‐S)], 2 (Scheme The reaction of a suspension of K{18c6}FeL (L=‐N(Di2 features two three‐coordinate iron(II) ions bridged by a single sulfide in a nearly linear fashion (Fe‐S‐Fe 167.78(2)°) with slightly different Fe−S distances of 2.2400(5) Å and 2.337(5) Å  complex bearing an unsupported sulfide bridge.2 can be adjusted accordingly. The cyclic voltammogram of 2 in THF showed two quasi‐reversible one‐electron oxidation processes at E1/2=−1.55 V and −0.55 V 2] (monoanionic ligand L−=nacnac) reported by Driess and co‐workers features redox events in THF at E1/2=−1.45 V for the [2Fe‐2S]2+/1+ and E1/2=−2.55 V (ΔE1/2=1.10 V) for the [2Fe‐2S]1+/0 redox couple.2(μ‐S)2]2− 2+ core in MeCN occurred at E1/2=−1.14 V ([2Fe‐2S]2+/1+) and E1/2=−2.10 V .2 (ΔE1/2=0.98 V). In contrast, the positions of the redox events of these bis(μ‐sulfido) complexes are shifted by around 0.9 V or 0.6 V to lower potentials, respectively, reflecting the additional sulfide ligation and higher coordination number of the iron ions in the two previously reported [2Fe‐2S] systems.[The related bis(μ‐sulfido) diferric complex [(LFe)2. Treatment of 2 with one equivalent of AgOTf in Et2O yielded reddish K{18c6}[(L2Fe)2(μ‐S)], 3  led to a colour change to dark green, and the neutral complex [(L2Fe)2(μ‐S)], 4, was obtained from a saturated pentane solution.Given the electrochemical data we attempted the chemical oxidation of 3 Scheme . Treatme3 and 4 are shown in Table 2, complexes 3 and 4 retain both a more or less linear Fe‐S‐Fe core. A gradual decrease of the Fe−S and Fe−N bond lengths was observed upon oxidation due to the contraction of the ionic radii of the metal ions. The structural features found for both iron ions are largely identical in 3 and 4, which prohibited an assignment of localized oxidation states for mixed‐valent 3 on a structural level.Important structural parameters of 2 showed no absorption beyond 400 nm , 470 nm (ϵ=9540 L mol−1 cm) and 700 nm (ϵ=2270 L mol−1 cm), and it is tempting to assign the low‐energy absorption to an intervalence charge transfer (IVCT) transition. For 4 just one pronounced band at 430 nm (ϵ=5710 L mol−1 cm) was observed. Zero field 57Fe Mössbauer spectroscopy  complex.δ=0.86 mm s−1 and |ΔEQ|=0.58 mm s−1), which can be explained by the weaker donor strength of the silylamide ligands as well as a less distorted trigonal planar ligand arrangement.4 is represented by a doublet with δ=0.29 mm s−1 and |ΔEQ|=3.70 mm s−1 indicating the presence of high‐spin iron(III) ions. The spectrum of the mixed valent complex 3, recorded at 7 K, showed two doublets with δ=0.36 mm s−1 (|ΔEQ|=3.70 mm s−1) and δ=0.57 mm s−1 (|ΔEQ|=0.71 mm s−1). This evidences distinguishable iron(II/III) positions in solid 3 on the 57Fe Mössbauer timescale at 7 K, whereas the smaller separation in the isomer shifts (Δδ(3)=0.21 mm s−1 vs. Δδ(2/4)=0.30 mm s−1) is indicative of some degree of valence delocalisation. Given the lack of literature precedence of the three‐coordinate μ‐sulfido complexes 3 and 4 their Mössbauer spectroscopic features are compared best to low coordinate iron complexes bearing a [2Fe‐2S] motif in the same oxidation states.[With this unprecedented series of low‐coordinate 2Fe‐1S] complexes in three different oxidation states in hand, their spectroscopic and electronic features were studied in detail. UV/Vis spectroscopic examination of m Figure , which iy Figure  revealedS complex2–4 in solid state were obtained by SQUID measurements  (S=2) ions with a S=0 ground state. The coupling constant was determined to be J=−53 cm−1 using Ĥ=−2JSA⋅SB with g1=g2=2.01.Additional insights into the electronic situation of s Figure –F. 2 exh3 showed at 295 K a significantly lower χT value of 0.96 cm3 mol−1 K which decreased to 0.44 cm3 mol−1 K at 80 K with a further drop to 0.38 cm3 mol−1 K below 20 K, which implies a ground state of S=1/2. The antiferromagnetic coupling is stronger with J=−115 cm−1 . For the all‐ferric compound 4 a similar value J=−104 cm−1  was observed with χT=1.3 cm3⋅mol−1⋅K at 300 K that decreased linearly to ca. 0.2 cm3 mol−1 K below 50 K due to a S=0 ground state. The differences in exchange coupling can be explained using a simplified orbital scheme under assumption of an idealized C2V symmetric ligand environment for each iron atom . Upon oxidation, electrons are removed from the lowest‐lying, co‐parallel dxy/dx2‐y2 orbitals, which have no impact onto the exchange mechanism. As such the variation in J values for 2–4 can be mainly attributed to differences in Fe⋅⋅⋅Fe distances, with different superexchange contributions due to changes in Fe‐(μ‐S) covalency likely playing a further role. A significant stabilization of the antiferromagnetically coupled ground state upon oxidation from the diiron(II) to the mixed‐valent iron(II)/iron(III) and diiron(III) states was observed for the series of complexes [(LFe)2(μ‐S)2]4−/3−/2− (L2−=bis(benzimidazolato))., 5  thiocarbonate complex 7, which could alternatively be obtained via the oxidation of 6 by silver triflate. For the neutral complex 4 the reaction with CS2 remained inconclusive. The observation of facile Fe–S bond cleavages suggests a rather weak FeII–S interaction. The displacement of an iron(II) ion by other Lewis acids has possible implications for the situation found in the FeMo cofactor where cleavage of the belt Fe‐S‐Fe unit is discussed during substrate turnover using the local Lewis acid/base properties of the surroundings of the enzyme pocket.2 into a [Fe‐S‐Fe] function also reveals how CS2 might act as an inhibitor of nitrogenase FeMoco (and other iron‐sulfur clusters) which is thought to proceed by blocking of coordination sites3+ complex localized valence states in solid state at low temperatures. Magnetic measurements revealed for the diferrous [2Fe‐1S]2+ a moderate antiferromagnetic coupling which becomes significantly enhanced for the [2Fe‐1S]3+ and [2Fe‐1S]4+ compounds. Reactivity studies on these complexes towards different nitrogenase relevant substrates revealed for CS2 the facile cleavage of the Fe‐S‐Fe unit. This led to the formation of an iron thiocarbonate which may suggest a possible inhibitory mechanism of CS2 with respect to the reactivity of FeMoco and related Fe/S clusters.We have synthesized a unique series of low‐coordinate [Fe‐S‐Fe] complexes in three oxidation states which resembles a Fe‐S‐Fe belt unit in the iron/sulfur/molybdenum co‐factor of the nitrogenase enzyme. These complexes were characterized for their magnetic and spectroscopic properties. 2] was synthesized according to the literature procedure. For details concernining data acquisition of solution and solid‐state analyses , see the Supporting Information.General considerations: All manipulations were carried out in a glovebox, or using Schlenk‐type techniques under a dry argon atmosphere. Used solvents were dried by continuous distillation over sodium metal for several days, degassed via three freeze‐pump cycles and stored over molecular sieves 4 Å. K{18c6}[FeL2[(FeL2)2(μ‐S)] (2)[K{18 c6}]: [K{18c6}][FeL2], 1,  was suspended in 5 mL of Et2O. The slow addition of elemental sulfur  led to an immediate colour change of the solution from red to brown and the precipitation of a pale yellow solid. Decanting off the supernatant, washing the residue with 2×5 mL of pentane and drying under reduced pressure afforded the crude product as a pale yellow crystalline solid. Recrystallization in THF/ pentane at −35 °C led to colourless crystals of 2 , suitable for X‐ray diffraction. 1H‐NMR : δ=14.23, 9.30, 3.50, 1.96, −0.94, −1.70 ppm. Evans: : effμ=3.98 μB.FT‐IR (ATR): (cm−1): v̄=2896 (w), 1418 (w), 1352 (w), 1314 (w), 1235 (m), 1192 (w), 1103 (vs.), 962 (w), 907 (s), 835 (vs.), 775 (s), 664 (w), 529 (w), 423 (m). CHNS: calc. (C84H152Fe2K2N4O12Si4S 1744.44 g mol−1): C 57.84 H 8.78 N 3.21 S 1.84 found: C 57.93 H 8.69 N 3.58 S 1.36.2)2(μ‐S)] (3)[K{18 c6}][(FeL: [K{18c6}]2[(FeL2)2(μ‐S)], 2,  was suspended in 5 mL of Et2O. Upon the addition of AgOTf  the pale yellow suspension turned into a red solution with beginning precipitation of a dark solid . After stirring for 2 hours, the mixture was filtered, the residue washed with 2×3 mL Et2O and the combined filtrates were layered with 5 mL of pentane. Storing the solution at −35 °C for several days yielded to a dark red crystalline solid, suitable for X‐ray diffraction analysis. Decanting off the supernatant, washing the residue with 2×5 mL of pentane and drying under reduced pressure afforded [K{18c6}][(FeL2)2(μ‐S)], 3, as a dark red crystalline solid . The aforementioned procedure to synthesize 3 leads to a pure product according to elemental analysis (vide infra). To obtain a magnetically pure sample several recrystallization steps in Et2O/pentane were required, which led to a decrease of the yield to less than 10 %. 1H‐NMR: : δ=14.58, 14.10, 3.26, 3.07, −0.92, −2.01 ppm. Evans: : effμ=3.70 μB. FT‐IR (ATR): (cm−1): v̄=2954 (w), 1456 (w), 1421 (m), 1353 (w), 1309 (w), 1232 (s), 1179 (s), 1101 (vs.), 961 (m), 896 (m), 832 (vs.), 781 (vs.), 733 (s), 673 (s), 637 (w), 541 (m), 434 (s). UV/VIS (THF): λ/ nm (ϵ/ L mol−1 cm)=380 (11 800), 470 (9540), 700 (2270). CHNS: calc. (C72H128Fe2K1N4O6Si4S 1441.03 g mol−1): C 60.01 H 8.95 N 3.89 S 2.22 found: C 59.66 H 8.64 N 4.07 S 1.51.2)2(μ‐S)] (4)[(FeL: [K{18c6}]2[(FeL2)2(μ‐S)], 2,  was suspended in 5 mL of Et2O. Upon the addition of AgOTf  the pale yellow suspension turned into a dark green solution and a dark precipitate. After stirring for 2 hours, the mixture was filtered, the residue washed 2 times with 3 mL of Et2O and the combined filtrates were dried in vacuo. The residue was extracted with 5 mL of pentane. The solution was concentrated to 0.5 mL in vacuo and stored at −30 °C for several days. This resulted in the deposition of a dark green crystalline solid, suitable for X‐ray diffraction. Decanting off the supernatant and drying under reduced pressure afforded [(FeL2)2(μ‐S)], 4, as a dark green crystalline solid . 1H‐NMR: : δ=64.37, 34.82, 23.62, −0.89, −26.88 ppm. Evans: : effμ=7.26 μB. FT‐IR (ATR): (cm−1): v̄=2958 (m), 1423 (w), 1360 (w), 1310 (w), 1242 (s), 1169 (m), 1100 (s), 1024 (s), 908 (m), 826 (vs.), 783 (vs.), 728 (vs.), 678 (s), 632 (m), 535 (s), 436 (s). UV/VIS (THF): λ/ nm (ϵ/ L mol−1 cm)=430 (5710). CHNS: calc. (C60H104Fe2N4Si4S 1137.61 g mol−1): C 63.35 H 9.22 N 4.94 S 2.83 found: C 63.97 H 8.75 N 5.42 S 2.65.2[L2FeII(η2‐CS3)] (5)[K(18‐crown‐6]: [K{18c6}]2[(FeL2)2(μ‐S)], 2,  was dissolved in 2 mL of THF. The slow addition of CS2  led to a colour change of the solution from brown to clear orange. After stirring for 2 hours, the mixture was filtered and the filtrate layered by 20 mL of pentane. Storing the solution at −35 °C yielded to the precipitation of orange crystals, suitable for X‐ray diffraction. Decanting off the supernatant, washing of the residue with 2×5 mL of pentane and drying in vacuo afforded 5 as a dark orange crystalline solid . 1H‐NMR: : no identifiable signals besides for K{18c6}. FT‐IR (ATR): (cm−1): v̄=2954 (m), 2892 (m), 1453 (m), 1422 (m), 1350 (m), 1311 (w), 1234 (s), 1188 (m), 1104 (vs.), 1054 (m), 961 (s), 920 (s), 881 (m), 834 (vs.), 777 (s), 744 (m), 664 (m), 533 (m), 434 (m), 407 (w). CHN: calc. (C55H101Fe2K2N2O12Si2S3⋅THF 1268.81 g mol−1): C 52.89 H 8.19 N 2.09 S 7.18 found: C 52.39 H 7.91 N 2.60 S 6.73.2[L2FeIII(η2‐CS3)] (6)[K(18 c6]: [K(18c6]2[L2FeII(η2‐CS3)], 5,  was dissolved in 2 mL of THF. Upon the addition of AgOTf  the solution turned dark red and the precipitation of a grey solid was observable. After stirring for 2 hours, the mixture was filtered and the filtrate was layered with 2 mL of pentane. Storing the solution at −35 °C for several days led to the precipitation of dark red crystals, suitable for X‐ray diffraction. Decanting off the supernatant, washing of the residue with 2×5 mL of pentane and drying in vacuo afforded 6 as a dark red crystalline solid. K(18c6)OTf is the major side product of the reaction. As it has almost the same solubility as 6 in Et2O and THF, it was impossible to obtain an analytically pure sample of 6 upon recrystallization. Therefore 6 could only be characterized by X‐ray diffraction. It exhibits no identifiable 1H NMR spectroscopic signature.2), 2048164 (3), 2048165 (4), 2048166 (5) and 2048167 (6)Deposition Numbers 2048098  should be addressed to the authors.SupplementaryClick here for additional data file.


Post-etch cleaning and silane application have been proven to increase bond strength, however, this step varies for each material [All-ceramic restorations currently dominate the market of indirect restorative materials due to their biocompatibility, longevity and superior aesthetics . Silica-material . The aimG1 BIS-Silane ; G2 ESPE Sil Silane Coupling Agent ; G3 Monobond Plus . Each was then divided into two subgroups, according to the surface conditioning time: T1 (1 min.) or T2 (5 min.). Each block was acid etched (HF 9.5% − 1 min), post-etching cleaned  and silanized. Heat treatment was carried out at 100 °C (1 min.). Then a thin layer of Optibond FL (Kerr) adhesive was applied and each block was adhered to pre-heated resin at 55 °C. The samples were light cured for 40 s on each side (1200 mW/cm2). Samples were sectioned into microspecimens (1 ± 0.2 mm2) that were subjected to aging . The microspecimens were tested in tension at a crosshead speed of 0.5 mm/min, until they debonded. Data analysis was carried out by a two-way ANOVA, at a significance level of 5%.Ten leucite reinforced glass ceramic blocks (IPS Empress CAD LT BL4/C 14) were divided into equal halves. Of the samples obtained, 6 were randomly divided into three groups according to the silane used: p < .001). Monobond Plus registered the lowest mean µTBS value (G3T1 − 18.5 ± 7.3 MPa) and (G3T2 − 17.3 ± 5.8 MPa). The type of silane coupling agent has shown to have a significant influence on the microtensile bond strength .The group featuring BIS-Silane with longer application time (G1T2) presented a mean µTBS value (32.4 ± 19.6 MPa) significantly higher to all other groups (Some authors have previously suggested that silanization could benefit from longer application times, but seldom research has been found featuring this variation protocol ,4. Silan


Additionally, the supramolecular interactions were determined by Hirshfeld surface analysis to investigate the influence of these contacts on the crystal packing. 17H30NSi+·C2H5O4S−, belongs to the class of a-aminosilanes and was synthesized by the alkylation of 1-[(benzyldimethylsilyl)methyl]piperidine using diethyl sulfate. This achiral salt crystallizes in the chiral space group P21. One of the Si—C bonds in the cation is unusually long [1.9075 (12) Å], which correlates with the adjacent quaternary N+ atom and was verified by quantum chemical calculations. In the crystal, the components are linked by weak C—H⋯O hydrogen bonds: a Hirshfeld surface analysis was performed to further investigate these intermolecular interactions and their effects on the crystal packing.The title molecular salt, C Consequently, the π-character of the Si—C bond is more pronounced, leading to an elongation of the bond. Thus, a selective cleavage of the amino functionality due to the elongated Si—C bond is also conceivable , the title compound, represents a compound that could lead to an extension of the aforementioned Si—C bond to the nitrogen atom via the quaternary ammonium cation. Structural studies concerning this type of compound should better elucidate the reactivity as well as selectivity of Si—C cleavages of the benzyl-substituted α-aminosilanes.Several derivates of these α-piperdinobenzylsilanes have been synthesized by our research group: 1-[(benzyldimethylsilyl)methyl]-1-ethylpiperidin-1-ium ethanesulfonate  symmetry. The chiral space group indicates that the achiral compound in the elementary cell is packed chirally; the Flack absolute structure parameter amounts to −0.005 (6) ° (C7—Si1—C10) and the largest angle of 114.32 (7)° (C8—Si1—C10). This geometric distortion has been observed in many complex substituted silicon compounds and depends on the substituents  to 167 (2)° (C3—H3⋯O2i). The shortest hydrogen-bond length is 3.1815 (16) Å and is the strongest supramolecular interaction with an angle of 162.8 (17)° (C17—H17A⋯O4). Analysis of the hydrogen-bonding network shows that all the hydrogen bonds shown in Table 2D11(2); Etter et al., 1990The crystal packing along the α-aminosilane derivatives that are structurally based on compound 1 and its starting compound 2. Examples of such α-piperidinosilanes found in the Cambridge Structural Database -1-methyl-1-{[methyl(phenyl)(trimethylgermyl)silyl]methyl}piperidinium iodide, C17H32GeNSiI methyl]gallium n-pentane solvate, C45H67GaN2Si4·0.5(C5H12) -5,6-aza-C60fulleroid, C79H17NSi  (0.81 mmol) was dissolved in acetone (3 ml) and diethyl sulfate (0.81 mmol) was added dropwise to the solution. The reaction mixture was stirred and heated for 6 h at 329 K. Afterwards the reaction was quenched by the addition of a mixture of H2O (2 ml) and NH3 (2 ml). The aqueous phase was extracted three times with CH2Cl2 and the combined organic phases were dried over Na2SO4. After the removal of volatile compounds, the raw product was dissolved in n-pentane (1 ml) and stored at 243 K. The title salt (1) was isolated as colorless crystalline blocks.The reaction scheme for the synthesis of 1H NMR : δ = 0.30 , 1.24–1.31 , 1.65–1.90 , 2.29 , 3.12 , 3.37–3.56 , 4.12 , 7.04 , 7.10–7.15 , 7.24  ppm.Uiso(H).Crystal data, data collection and structure refinement details are summarized in Table 310.1107/S205698902101361X/hb8003sup1.cifCrystal structure: contains datablock(s) I. DOI: 10.1107/S205698902101361X/hb8003Isup2.hklStructure factors: contains datablock(s) I. DOI: Click here for additional data file.10.1107/S205698902101361X/hb8003Isup3.cmlSupporting information file. DOI: 2131144CCDC reference:  crystallographicinformation; 3D view; checkCIF reportAdditional supporting information:


I atom in the title compound, which exhibits strong blue emission, adopts a highly distorted trigonal–planar geometry coordinated by two pyridine N atoms of two crystallographically independent 2′,6′-difluoro-2,3′-bipyridine ligands and one O atom of the trifluorometanesulfonate anion.The Ag 3SO3)(C10H6F2N2)2], the AgI centre adopts a highly distorted trigonal–planar coordination environment resulting from its coordination by one O atom of the trifluoromethanesulfonate anion and the pyridine N atoms of two crystallographically independent 2′,6′-difluoro-2,3′-bipyridine ligands, which display very similar conformations to one another. Pairwise Ag⋯O–SO2CF3− [Ag⋯O = 2.8314 (14) Å] interactions and intermolecular C—H⋯O interactions between inversion-related units lead to the formation of an eight-membered cyclic dimer in which the silver atoms are separated by 6.2152 (3) Å. In the crystal, the dimers are linked through C—H⋯O hydrogen bonds, halogen⋯π and weak π–π stacking interactions, resulting in the formation of a three-dimensional supramolecular network. The title compound exhibits a strong and broad emission band from 400 nm to 550 nm in solution and its photoluminescence quantum efficiency is estimated to be ca 0.2, indicating that the title compound could have applications as an emitting material in organic light-emitting diodes (OLEDs).In the title compound, [Ag(CF III and PtII complexes by many researchers because of their applicability to OLEDs and solid-state lighting  and 53.10 (7)°, respectively. As shown in Fig. 1I ion is coordinated by two pyridine N atoms (N2 and N4) from two 2′,6′-difluoro-2,3′-bipyridine ligands and one O atom from the trifluoromethanesulfonate anion, forming a highly distorted trigonal–planar geometry. Selected bond lengths and angles around the Ag1 atom are given in Table 12CF3− interaction between the metal ion and an O atom of an adjacent trifluoromethanesulfonate anion . The AgI atom is displaced out of the trigonal N2, N4, O1 coordination plane by 0.1057 (9) Å. The C6–C10/N2 and C16–C20/N4 pyridine rings coordinated to the AgI centre are tilted by 25.75 (10)° with respect to each other. The pairwise Ag⋯O links lead to the formation of an eight-membered [Ag—O—S—O—]2 cyclic dimer, in which the silver atoms are separated by 6.2152 (3) Å. The cyclic dimer is consolidated by C—H⋯O interactions (Table 2The asymmetric unit in the title compound consists of an Ags Table 2.Cg4⋯Cg4ii = 3.9737 (11) Å; Cg4 is the centroid of the C16–C20/N4 ring; symmetry code: (ii) −x, −y, −z + 1] between the pyridine rings, forming a chain structure propagating along the a-axis direction. Neighbouring chains are connected by halogen⋯π interactions , thereby generating a two-dimensional supramolecular network lying parallel to the ab plane. Finally, these networks are stacked along the c-axis direction and connected by halogen⋯π and weak π–π stacking interactions , resulting in the formation of a three-dimensional supramolecular network.In the extended structure, the dimers are linked through C19—H19⋯O3 hydrogen bonds Table 2 and weak2Cl2 solution, the title compound exhibits a strong and broad emission band with λmax = 400 nm, as shown in Fig. 53SO3) unit, significant blue-shifted emissions (> 50 nm) are observed as compared with bipyridine based IrIII complexes . The observed emission of the title compound is therefore attributed to ligand-centered π–π* transitions with a minor contribution of an Ag-based metal-to-ligand charge-transfer transition. Similar dual-emission behaviour has been noted for some AgI complexes with 2-methylthiothiazole   in MeOH (2 ml) in the dark at room temperature and the mixture was stirred for 10 min. After that, the mixture was slowly evaporated in the air and a dark environment to obtain crystals suitable for X-ray crystallographic analysis. 1H NMR  δ 8.67 , 8.62 , 7.88–7.80 , 7.37–7.34 , 7.0.8 . 19F NMR  δ −69.7, −71.8, 79.1. Analysis calculated for C21H12F7N4O3SAg: C 39.33; H 1.89; N 8.74%; found: C 39.44, H 1.86, N 8.70%.All experiments were performed under a dry NUiso(H) = 1.2Ueq(C).Crystal data, data collection and structure refinement details are summarized in Table 310.1107/S2056989021011282/hb7990sup1.cifCrystal structure: contains datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S2056989021011282/hb7990Isup2.hklStructure factors: contains datablock(s) I. DOI: 2118061CCDC reference:  crystallographicinformation; 3D view; checkCIF reportAdditional supporting information:


The salan ligands coordinate to the molybdenum center in a κ2N,κ2O fashion, forming a distorted octahedral geometry. These complexes crystallized as dimethylformamide and methanol solvated species.Two  cis-dioxomolybdenum complexes based on salan ligands with different backbones are reported. The first complex, dioxido{2,2′-bis(phenolato)}molybdenum(VI) dimethylformamide disolvate, [Mo(C20H18N2O2)O2]·2C3H7NO , features a phenyl backbone, while the second complex, bis(azanediyl)]bis(methylene)}bis)dioxidomolybdenum(VI) methanol disolvate, [Mo(C36H56N2O2)O2]·2CH3OH , is based on a cyclohexyl backbone. These complexes crystallized as solvated species, 1b·2DMF and 2b·2MeOH. The salan ligands PhLH2 (1a) and CyLH2 (2a) coordinate to the molybdenum center in these complexes 1b and 2b in a κ2N,κ2O fashion, forming a distorted octahedral geometry. The Mo—N and Mo—O distances are 2.3475 (16) and 1.9567 (16) Å, respectively, in 1b while the corresponding measurements are Mo—N = 2.3412 (12) Å, and Mo—O = 1.9428 (10) Å for 2b. A key geometrical feature is that the N—Mo—N angle of 72.40 (4)° in CyLMoO2 is slightly less than that of the PhLMoO2 angle of 75.18 (6)°, which is attributed to the flexibility of the cyclohexane ring between the nitrogen as compared to the rigid phenyl ring in the PhLMoO2.Two  In this system, the salan ligand PhLH2 (1a) coordinates to the molybdenum center in a κ2N,κ2O fashion, forming a distorted octahedral geometry. The angles formed around the molybdenum core are 80.23 (6)° for O1—Mo01—N1, 157.78 (6)° for O1—Mo01—O2, 75.18 (6)° for N1—Mo01—N2, and 109.80 (7)° for O3—Mo01—O4. These angles are consistent with a system that is significantly distorted from octahedral geometry with bond angles resulting from the salan ligand ranging from 75.18 (6) to 84.38 (7)°, while the angle between the ‘oxo’ oxygens of 109.80 (7)° is close to the ideal tetrahedral angle of 109.5°. Analogous bond angles in the second molecule in the unit cell are the same within 0.01 Å. The bond distances between the molybdenum center and ligand atoms for Mo01—N1 and Mo01—O1 are 2.3475 (16) and 1.9567 (16) Å, respectively. The notable bond distances from the salan ligand are O1—C1 at 1.377 (2) Å, N1—C7 at 1.486 (3) Å, C2—C7 at 1.515 (3) Å, N1—C8 at 1.389 (8) Å, and C8—C13 at 1.419 (3) Å. Analogous bond distances in the second molecule in the unit cell are the same within 0.01 Å as distances for O1—C1 and N1—C8, respectively. The other bond distances have variations of 0.2–0.3 Å, with N3—C27 at 1.519 (3) Å, C26—C27 at 1.490 (3) Å, and C28—C33 at 1.392 (3) Å.The asymmetric unit of CyLMoO2 (2b) contains one molecule of CyLMoO2 and two molecules of methanol (MeOH)  binds in the same κ2N,κ2O fashion that complex 1b does. Fig. 4CyLMoO2 with the hydrogen atoms removed for clarity. The complex also has a distorted octahedral geometry with angles of O3—Mo01—O1 at 96.36 (5)°, O1—Mo01—N1 at 76.73 (4)°, N1—Mo01—N2 at 72.40 (4)°, N2—Mo01—O2 at 78.91 (4)°, O2—Mo01—O4 at 100.19 (5)°, O2—Mo01—O3 at 94.58 (5)°. These angles are between 5 and 10° of the ideal 90° for octahedral geometry. The N1—Mo01—N2 angle at 72.40 (4)° is slightly less than that of the PhLMoO2 angle of 75.81 (6)°, which is attributed to the flexibility of the cyclohexane ring between the nitrogen atoms compared to the rigid phenyl ring in the PhLMoO2. Metal–ligand bond distances are found for Mo01—O1 at 1.9428 (10) Å, Mo01—O2 at 1.9484 (10) Å, Mo01—O3 at 1.7125 (10) Å, Mo01—O4 at 1.7226 (11) Å, Mo01—N1 at 2.3412 (12) Å, and Mo01—N2 at 2.3384 (12) Å. Other ligand distances and bond lengths within the phenyl rings are consistent with analagous distances in PhLMoO2 (1b). The cylohexane bond distances are consistent with single C—C bonds. The bond lengths observed are not statistically different than those reported by Ziegler et al. (2009R1 of 2.78% as compared to the previously reported R1 of 5.5% and higher solvent disorder in the reported structure.The asymmetric unit of H) Fig. 3. The sal al. 2009. There aPhLMoO2 (1b): A single molecule of PhLMoO2 is hydrogen bonded to one disordered DMF molecule, as shown in Fig. 5D with a distance of 2.16 (3) Å. Corresponding hydrogen bond distances in the second molecule in the unit cell are similar. There are three formula units within the contents of the unit cell. Perpendicular π-stacking between PhLMoO2 molecules is observed between C5 and the aryl ring centroid (C35–C39) with a distance of 4.597 Å.CyLMoO2 (2b): There are four molecules of CyLMoO2 in the unit cell of this system and the complex is stabilized via hydrogen bonding to the solvent MeOH molecule . There was a similar crystal structure found with the imine form of the ligand MoO2. A search for CyLMoO2 (2b) in the CSD  shows that there is a known structure of the molecule with a different unit cell with accession code HUWGOW  was solved in space group P 21/n compared with P31 for HUWGOW. The primary additional differences in the structures is an improved R1 of 2.78% and more clearly resolved methanol solvent, as compared to the previously reported R1 of 5.5% and more disordered methanol solvent    and CyLH2 (2a) were synthesized as off-white solids in 86% and 58% yields, respectively. The reaction scheme is shown in Fig. 71H NMR spectra of both ligands as compared to the precursor salen compounds was the disappearance of the aldimine peak (∼8.50 ppm) and the appearance of the benzylic resonances ∼4.00 ppm. The molybdenum complexes PhLMoO2 (1b) and CyLMoO2 (2b) were synthesized in 86% and 42% yields, respectively, by the reaction of the corresponding ligands with MoO2(acac)2 in methanol or acetonitrile as solvent. Complexes 1b and 2b were also characterized by NMR and IR spectroscopy. Both complexes exhibited stretches { characteristic of a cis-dioxo molybdenum core in the IR spectrum.The salan ligands used for stabilizing molybdenum(VI) )dioxidomolybdenum(VI) : A round-bottom flask equipped with a magnetic stirring bar was charged with MoO2(acac)2  and methanol (ca. 10 mL). The solution was stirred, and 2a  was added to the MoO2(acac)2 dissolved in methanol. The solution was stirred overnight when it turned orange. The solution was filtered, and the solvent removed by evaporation under vacuum to obtain an orange precipitate. The precipitate was triturated with methanol, producing an orange solid, which was separated by gravity filtration and was washed twice with cold methanol . 1H NMR  δ 7.26 , 6.86 , 5.28 , 4.18 , 2.34–2.28 , 1.43 , 1.30 , 1.19–1.17 , 0.88–0.85 . 13C{1H} NMR  δ 157.1, 152.1, 142.8, 142.3, 142.0, 138.0, 137.7, 137.6, 125.7, 125.4, 124.1, 124.0, 123.0, 122.9, 120.0, 119.6, 65.19, 58.9, 57.6, 53.4, 50.9, 50.5, 35.2, 35.1, 34.3, 34.2, 33.0, 31.6, 31.6, 31.5, 29.9, 29.9, 28.9, 24.5, 24.3, 24.1. Selected IR (cm−1): 903, 875 υ(Mo=O).bis(azanediyl)]bis(methylene)}bis = 1.2Ueq(C) for CH, CH2, and CH3. The structure for PhMoO2 (1b) was initially refined in the trigonal crystal system P3221; however, this resulted in the solvent DMF having a high level of disorder with many checkCIF errors.Crystal data, data collection, and refinement details are listed in Table 410.1107/S2056989022000524/tx2046sup1.cifCrystal structure: contains datablock(s) 2b, 1b. DOI: 10.1107/S2056989022000524/tx20462bsup3.hklStructure factors: contains datablock(s) 2b. DOI: 10.1107/S2056989022000524/tx20461bsup2.hklStructure factors: contains datablock(s) 1b. DOI: 2142074, 2142073CCDC references:  crystallographicinformation; 3D view; checkCIF reportAdditional supporting information:


A three-dimensional network of hydrogen bonds serves to hold the structure together.The polymer contains Li 4(C3H2N3O3)4(H2O)7]n, synthesized at room temperature from an aqueous solution of lithium hydroxide and cyanuric chloride, crystallizes in the triclinic space group P+ cations in the asymmetric unit, one of which, Li1, has distorted trigonal–bipyramidal geometry and is coordinated via oxygen to two cyanurate anions occupying equatorial positions, and three water molecules, two in the axial positions and the third in an equatorial position. One of the axial water ligands and the equatorial water ligand are involved in bridging to a crystallographically equivalent Li1 cation. A centre of inversion lies between the two Li1 cations and the Li1⋯Li1 distance is 3.037 (5) Å. The remaining axial water ligand bridges to the second Li cation, Li2, which is disordered over two crystallographic sites with approximately equal occupancy, and has an Li1⋯Li2 distance of 3.438 (7) Å. The terminal Li2 cation is coordinated to three water molecules and an oxygen atom from a cyanuric anion and has a distorted tetrahedral geometry. A three-dimensional network of intermolecular hydrogen bonds involving N—H⋯O, O—H⋯O and O—H⋯N interactions serves to hold the structure together. The title compound was further characterized using IR and UV–vis spectroscopy and TG–DTA analysis.The polymeric title complex, poly[hexa-μ-aqua-diaquatetra-μ-cyanurato-tetralithium] [Li The complex has been characterized by single-crystal X-ray diffraction, FTIR and UV–Vis spectroscopy, and TG–DTA analysis.As cyanuric acid has three hydrogen-bonding-donor amine sites and three hydrogen-bonding-acceptor keto sites, it has been the subject of several structural and crystal-design studies 4(H2O)7] . This coordination preference may be due to the hard acid, Li+, preferring to bond to the harder base i.e. oxygen.The two crystallographically distinct cyanurate ligands exist in resonance form (IV) Fig. 1, in whicet al., 2020A and Li2B) and have slightly longer bond lengths: C2—O3, 1.2439 (18) Å; C3—O2, 1.2436 (19) Å; C5—O5, 1.2442 (18) Å and C6—O6, 1.2430 (18) Å. The delocalization of the negative charge on the deprotonated nitrogen atoms (N2 and N5) over the adjacent keto groups is shown as dashed lines in Fig. 2The C=O groups involved in coordination to Li1, namely C1=O1 and C4=O4 have bond lengths of 1.2207 (19) and 1.2242 (19) Å, respectively Fig. 3, which a+ cations in the asymmetric unit  in the axial positions and the third (H2O8) in an equatorial position. The Li1—O bond lengths lie in the range 2.012 (3)– 2.201 (3) Å and the bond angles of O4—Li1—O1 = 118.40 (13)°, O4—Li1—O8 = 120.78 (14)°, O1—Li1—O8 = 120.74 (14)° and O8i—Li1—O7 = 178.56 (15)° confirm the trigonal–bipyramidal Li1 coordination geometry. One of the axial water ligands, H2O8i, and the equatorial water ligand, H2O7, bridge to a crystallographically equivalent Li1 cation. The Li1⋯Li1i distance is 3.037 (5) Å, which is larger than the Li—Li bond distance found in lithium metal. The Li1—O—Li1i bridge angle is 95.00 (11)°. The Li1—O8 and Li1—O8i bond lengths are 2.032 (3) and 2.086 (3) Å, respectively.There are two distinct Liit Fig. 3. Li1 has2O7, bridges to the second Li+ cation, Li2, which is disordered over two sites, Li2A and Li2B, which have approximately equal occupancies. The Li1⋯Li2A and Li1⋯Li2B distances are 3.438 (7) and 3.439 (7) Å, respectively. Li2 is coordinated to two more water molecules, H2O9, H2O10 and an oxygen atom from a cyanurate ligand (either O3ii for Li2A or O2iii for Li2B) to complete its distorted tetrahedral coordination geometry. The Li2—O bond lengths lie in the range 1.931 (7)–2.057 (7) Å and the O—Li2—O angles in the range 97.9 (3)–125.3 (3)°The remaining axial water ligand, H4(C3H2N3O3)4(H2O)7] units into a three-dimensional network  and 2.7443 (16) Å, respectively].Strong intermolecular hydrogen-bonding interactions Table 1 link therk Fig. 4. These ii, N3—H3⋯O5ii, N4—H4⋯O6iii and N6—H6⋯O6iv). Weaker hydrogen-bonding interactions, with N⋯O distances in the range 2.905 (2)–3.0342 (19) Å are also observed between the unprotonated N atoms of the cyanurate ions and nearby water molecules .In addition, each cyanurate moiety forms two strong hydrogen bonds between the N—H groups and oxygen atoms of adjacent molecules with N⋯O distances in the range 2.7964 (16)–2.8054 (17) Å bisdicopper(I) tetraaquastrontium(II)] bis(μ-aqua)tetraaquacopper(II)disodium(I)]  and 3389 cm−1 (br) correspond to ν(O—H)    1/2/hν, where t is the thickness of the crystal (1 mm) and hν is the photon energy. A plot of (αhν)2versus hν is shown as the inset in Fig. 7Eg) is estimated to be 5.22 eV.The UV–Vis NIR absorption spectrum was measured using a Perkin Elmer lambda 950 UV–Vis–NIR spectrophotometer Fig. 6. The pea−1 with a resolution of 1 µg under a dry N2 atmosphere. The thermogram  .Simultaneous TG–DTA measurements and analysis of weight change and heat flow were performed using a Perkin Elmer STA 6000 instrument operating at a scanning rate of 10°C minam Fig. 7 shows foLithium hydroxide  and cyanuric chloride  were dissolved in water (100 ml). The resulting solution was stirred for 5 h at ambient temperature (300-301 K) and filtered twice using Whatman filter paper. The solvent was allowed to evaporate in a dust-free environment. After 22 days, good quality colourless crystals were harvested.A and Li2B, which were resolved using the PART command  = 1.2Ueq(N). The hydrogen atoms on the water molecules were located in difference-Fourier maps and each Uiso(H) parameter was freely refined with the O—H distance restrained to 0.85 (2) Å using DFIX. The H—O—H angle distances were restrained using DFIX to a target value of 1.39 (2) Å [or 1.41 (2) Å for H9A—O9—H9B] in order to keep the water molecules close to their standard geometries.Crystal data, data collection and structure refinement details are summarized in Table 210.1107/S2056989021009324/cq2044sup1.cifCrystal structure: contains datablock(s) I. DOI: 10.1107/S2056989021009324/cq2044Isup2.hklStructure factors: contains datablock(s) I. DOI: 1991191CCDC reference:  crystallographic information; 3D view; checkCIF reportAdditional supporting information:


To evaluate the effect of toric intraocular lens implantation in cataract patients with irregular corneal steep and flat meridian.  Data of 112 eyes of 78 patients who underwent toric intraocular lens implantation were analyzed retrospectively. Steep meridian deviations (not 180°) and steep and flat meridian deviations (not 90°) were classified as 0, 1–9, 10–19, 20–29, 30–39, and over 30°. Meridian deviation was measured with a sagittal map of a rotating Scheimpflug camera  using PicPickTools . D) of 0  and 1–9  groups were significantly lower than that of 10–19 , 20–29 , and over 30° groups  both in steep meridian deviations and horizontal and vertical meridian deviations at 6 months (P < 0.05). Postoperative mean UCVA (logMAR) of 0  (logMAR) and 1–9  groups was significantly improved compared to that of 10–19 , 20–29 , and over 30° groups  both in steep meridian deviations and horizontal and vertical meridian deviations at 6 months (P < 0.05).  Residual astigmatism ( Correction of astigmatism with toric intraocular lens implantation is not accurate in corneas with steep meridian deviations and steep and flat meridian deviations of more than 10°. Therefore, care should be taken when we perform toric intraocular lens implantation in patients with irregular corneal meridian. D) of corneal astigmatism [D or greater [Cataract is the most common cause of visual impairment in elderly people . About 6igmatism , and 20% greater . If this greater . Toric i greater . Toric I greater . TherefoTo the best of our knowledge, no studies have reported the efficacy of toric IOL implantation in normal patients with irregular corneal astigmatism such as steep meridian deviations or steep and flat meridian deviation. Thus, the objective of this study was to evaluate outcomes of toric IOL implantation according to the amount of steep meridian deviations and angle deviation of steep and flat meridian.We performed a retrospective chart review and data analysis in this study. This study was conducted in compliance with Institutional Review Board regulations, informed consent regulations, sponsor and investigator obligations, and the Declaration of Helsinki. The Institutional Review Board (IRB)/Ethics Committee of Bucheon St. Mary Hospital approved this study protocol.A total of 112 eyes of 78 patients who underwent toric intraocular lens implantation in Bucheon St. Mary Hospital from July 2017 to April 2018 were enrolled. Steep meridian deviations (not 180°) were classified as 0, 1–9, 10–19, 20–29, 30–39, and over 30°. Steep and flat meridian deviations (not 90°) were classified as 0, 1–9, 10–19, 20–29, and over 30°. Inclusion criteria were advanced cataracts in patients with high corneal astigmatism more than 1.5D. Exclusion criteria were a history of any ocular injury or disorder, infection, inflammation, and surgery within prior 6 months.Steep meridian deviations and steep and flat meridian deviation were measured with a sagittal map of a rotating Scheimpflug camera  using PicPickTools . Steep meridian deviation was determined as an absolute value of 180 minus the steep axis angle. Steep and flat meridian deviation was determined as an absolute value of 90 minus steep and flat meridian angle .®, Oculus, Germany).All patients underwent a complete ophthalmological examination. Their demographic and perioperative data were recorded. Uncorrected and corrected distance visual acuities were expressed as logMAR. Manifest refraction, biometry, and keratometry with the IOLMaster partial coherence interferometry device (Carl Zeiss Meditec AG), corneal topography , slit lamp examination, and dilated funduscopy were examined at the preoperative period and postoperative 2, 4, and 6 months. The IOL manufacturer's web-based toric calculator was used to determine the required cylinder power and axis for the IOL that was going to be implanted. The total corneal astigmatism was measured using the Scheimpflug system  using an Intrepid Infiniti system . Corneal steep axis and 6.0 mm ring were marked with gentian violet. Surgery was performed through a clear corneal incision at the steep astigmatic axis. After topical ocular anesthesia was applied, a 2.75 mm clear corneal incision was made using a 2.75 mm double-blade keratome (Alcon). Surgically induced astigmatism was set by 0.5 diopters. Sodium hyaluronate 1.0%  was used to reform and stabilize the anterior chamber. A continuous curvilinear capsulotomy was made according to a 6.0 mm corneal marker using Inamura capsulorhexis forceps . Hydrodissection and hydrodelineation were achieved using a balanced salt solution. Phacoemulsification was performed using 2.75 mm-sized phacotips and infusion/aspiration (I/A) cannulas for micro- and small-incision groups, respectively. A clear preloaded IOL  was implanted in the capsular bag. The IOL was rotated to the correct axis position according to the axis of total corneal astigmatism. The wound was not sutured. Postoperative treatment consisted of gatifloxacin 0.3%  and fluorometholone acetate 0.01%  eye drops four times a day for four weeks.P values < 0.05 were considered statistically significant.All statistical analyses were performed using a commercial program . The Wilcoxon signed rank test was used to compare pre- and postoperative BCVA and refractive and keratometer astigmatisms. A total of 112 eyes of 78 patients were enrolled in this study. Preoperative mean autorefractive cylinder was 2.21 ± 1.36 D. Mean total corneal astigmatism measured with the Scheimpflug camera was 2.35 ± 1.15 D. Mean UCVA was 0.83 ± 0.35 (logMAR), and mean BCVA was 0.56 ± 0.29 (logMAR) .P < 0.05). Postoperative mean total corneal astigmatism (1.96 ± 1.0 D) was also decreased compared to preoperative value (2.35 ± 1.15 D), but the decrease was statistically insignificant. Mean IOL rotation was 3.2 ± 1.5° at 2 months after toric IOL implantation. Postoperative mean UCVA (0.09 ± 0.06) (logMAR) and mean BCVA (0.02 ± 0.01) were improved compared to preoperative values  (both P < 0.05)  was significantly decreased compared to its preoperative value (2.21 ± 1.36 D) ( < 0.05) .D) and mean UCVA (logMAR) of all groups were similar to each other . Postoperative mean UCVA (logMAR) of 0 (0.09 ± 0.04) (logMAR) and 1–9° (0.10 ± 0.04) groups was significantly improved compared to that of 10–19 (0.14 ± 0.05), 20–29 (0.18 ± 0.08), and over 30° groups (0.20 ± 0.09) in steep meridian deviations at 6 months  (D) values of 0 (0.51 ± 0.13) and 1–9° groups (0.61 ± 0.16) were significantly lower than those of 10–19 (0.92 ± 0.24), 20–29 (0.10 ± 0.32), and over 30° groups (1.12 ± 0.37) in steep meridian deviations at postoperative 6 months (P < 0.05) (D)   . Estimat < 0.05) . There w < 0.05) .P > 0.05). However, preoperative total corneal astigmatism (D) of 21–30° (2.04 ± 0.86 D) and over 30° groups (2.06 ± 1.05 D) was statistically higher than that of other groups  (P < 0.05). Postoperative mean UCVA (logMAR) values of 0 (0.09 ± 0.05) and 1–9° (0.11 ± 0.08) were significantly improved compared to those of 10–19 (0.17 ± 0.10), 20–29 (0.21 ± 0.10), and over 30° groups (0.22 ± 0.11) in steep and flat meridian deviations at 6 months (P < 0.05) (D) of 0 (0.55 ± 0.15) and 1–9° groups (0.66 ± 0.19) was significantly lower than that of 10–19 (0.90 ± 0.28), 20–29 (1.01 ± 0.35), and over 30° groups (1.14 ± 0.40) in steep and flat meridian deviations at postoperative 6 months (P < 0.05) (D)   values of all groups were similar to each other ( < 0.05) . Estimat < 0.05) . There w < 0.05) .D depending on preoperative astigmatism [Implantation of toric IOL in cataract surgery to correct corneal astigmatism has been popular due to its excellent clinical outcomes and increased patient demands . Howeverigmatism . Severaligmatism , ignorinigmatism , inaccurigmatism . Zhu et igmatism . In the If there are severe steep meridian deviations, the other marker of toric IOL and corneal steep meridian may be misaligned despite that surgeons have made a perfect alignment of one marker of toric IOL and corneal steep meridian. If there is a severe steep and flat meridian deviation, the toric IOL steep axis and corneal flat axis may be misaligned despite that the surgeon has made a perfect alignment of marker of toric IOL and corneal steep meridian.D) values of 0 (0.51 ± 0.13) and 1–9° groups (0.61 ± 0.16) were significantly lower than those of 10–19 (0.92 ± 0.24), 20–29 (0.10 ± 0.32), and over 30° groups (1.12 ± 0.37) in steep meridian deviations at postoperative 6 months (P < 0.05) (D) and mean UCVA (logMAR) values of all groups were similar to each other (P > 0.05). However, postoperative mean UCVA (logMAR) of 0 (0.09 ± 0.04) (logMAR) and 1–9° (0.10 ± 0.04) groups was significantly improved compared to that of 10–19 (0.14 ± 0.05), 20–29 (0.18 ± 0.08), and over 30° groups (0.20 ± 0.09) in steep meridian deviation at 6 months (P < 0.05)  . Preoper < 0.05) .D) values of 21–30° and over 30° groups were statistically higher than those of other groups (P < 0.05)  . We hypoD) of 0 (0.55 ± 0.15) and 1–9° groups (0.66 ± 0.19) were significantly lower than that of 10–19 (0.90 ± 0.28), 20–29 (1.01 ± 0.35), and over 30° groups (1.14 ± 0.40) in steep and flat meridian deviations at postoperative 6 months (P < 0.05) (P < 0.05)  . Also, p < 0.05) .D) at 6 months  (D)   . A posit < 0.05)  was alsoP < 0.05). Therefore, patients who had meridian deviations of less than 10° had significantly lower residual astigmatism and better uncorrected visual acuity than those who had meridian deviation of more than 10°.Toric IOL rotations of less than 10° changed the eye's refractive astigmatism to less than 0.50 diopters . In the D) also increased in patients with irregular corneal astigmatism. Therefore, the effect of toric IOL implantation is optimized in patients with regular corneal astigmatism. Toric IOL implantation should be performed cautiously when patients have steep meridian deviations or steep and flat meridian deviations.To the best of our knowledge, this was the first study to evaluate the outcomes of toric IOL implantation in cataract patients with irregular corneal astigmatism. The postoperative visual acuity of patients with regular astigmatism was significantly improved compared to that of patients with steep meridian deviations and the steep and flat meridian deviations. If steep meridian deviations and steep and flat meridian deviations increased, estimated residual astigmatism (A multicenter clinical trial with a larger sample size and longer follow-up period is needed to observe the long-term efficacy of toric intraocular lens implantation in cataract patients with irregular corneal astigmatism.