Search

The molecular and crystal structure of (E)-2-[(benzo[d]thiazol-2-ylimino)- methyl]-5-(diethylamino)phenol (C18H19N3O2S, Et2N-Bz) and its unexpected reaction product with triphenylborane, 2,2-diphenyl-1,3-dioxa-2-borata-1,2-dihydronaphthalene [systematic name: N,N-diethyl-2,2-diphenyl-2H-1,3λ³,2λ4-benzodioxaborinin-7-amine, C23H24BNO2, (I)] are described. For Et2N-Bz, the hydroxyl group is involved in an intramolecular hydrogen bond with the imino nitrogen atom and the C N bond displays an E configuration. The crystal packing is characterized by layers of inversion dimers parallel to the (101) plane and chains of molecule in the a-axis direction formed through C--H⋯O interactions. Complex (I) crystallizes with two molecules (A and B) in the asymmetric unit, which differ in the orientation of the ethyl groups. The 1,3- dioxa-2-borata-1,2,3,4-tetrahydronaphthalene ring displays a slight envelope conformation with the boron atom as the flap. In the crystal packing, chains of alternating A and B molecules formed by C--H⋯O hydrogen bonds run in the b-axis direction. The UV--vis absorption and emission properties of the compounds are discussed and their aggregation-induced emission properties are further investigated. [ABSTRACT FROM AUTHOR]

In this work, a novel compound N-(3-(4-methoxyphenyl)isoxazolin-5-yl)methylsaccharin has been synthesized. The molecular structure of the compound was determined using various spectroscopic techniques and confirmed by a single-crystal X-ray diffraction analysis. In the single crystal, C–H...O hydrogen bonds between neighboring molecules form chains along the a-axis direction. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H...H (35.7%), H...O/O...H (33.7%), and H...C/C...H (13%) interactions. The optimized structure calculated using density functional theory at the B3LYP/6–311 G(d,p) level is compared with the experimentally determined structure in the solid state. The calculated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gap is 4.9266 eV. [ABSTRACT FROM AUTHOR]

The synthesis, spectroscopic data, crystal and molecular structures of two N'-(1-phenylbenzylidene)-2-(thiophen-3-yl)acetohydrazides, namely N'-[1-(4-hydroxyphenyl)benzylidene]-2-(thiophen-3-yl)acetohydrazide, C13H10N2O2S,(3a), and N'-[1-(4-methoxyphenyl)benzylidene]-2-(thiophen-3-yl)acetohydrazide, C14H14N2O2S, (3b), are described. Both compounds differ in the substituent at the para position of the phenyl ring: -OH for (3a) and -OCH3 for (3b). In (3a), the thiophene ring is disordered over two orientations with occupancies of 0.762 (3) and 0.238 (3). The configuration about the C= N bond is E. The thiophene and phenyl rings are inclined by 84.0 (3) and 87.0 (9)° for the major- and minor-occupancy disorder components in (3a), and by 85.89 (12)° in (3b). Although these dihedral angles are similar, the conformation of the linker between the two rings is different [the C--C--C--N torsion angle is -ac for (3a) and -sc for (3b), while the C6--C7--N9--N10 torsion angle is +ap for (3a) and -sp for (3b)]. A common feature in the crystal packing of (3a) and (3b) is the presence of N--H···O hydrogen bonds, resulting in the formation of chains of molecules running along the b-axis direction in the case of (3a), or inversion dimers for (3b). The most prominent contributions to the surface contacts are those in which H atoms are involved, as confirmed by an analysis of the Hirshfeld surface. [ABSTRACT FROM AUTHOR]

Crystallization experiments with the dinuclear chelate ring complex di-μ-chlorido-bis[(η2-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κ C1)platinum(II)], [Pt2(C15H19O4)2Cl2], containing a derivative of the natural compound eugenol as ligand, have been performed. Using five different sets of crystallization conditions resulted in four different complexes which can be further used as starting compounds for the synthesis of Pt complexes with promising anticancer activities. In the case of vapour diffusion with the binary chloroform-diethyl ether or methylene chloride-diethyl ether systems, no change of the molecular structure was observed. Using evaporation from acetonitrile (at room temperature), dimethylformamide (DMF, at 313 K) or dimethyl sulfoxide (DMSO, at 313 K), however, resulted in the displacement of a chloride ligand by the solvent, giving, respectively, the mononuclear complexes (acetonitrile-κ N)(η2-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κ C1)chloridoplatinum(II) monohydrate, [Pt(C15H19O4)Cl(CH3CN)]·H2O, (η2-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κ C1)chlorido(dimethylformamide-κ O)platinum(II), [Pt(C15H19O4)Cl(C2H7NO)], and (η2-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κ C1)chlorido(dimethyl sulfoxide-κ S)platinum(II), determined as the analogue {η2-2-allyl-4-methoxy-5-[(ethoxycarbonyl)methoxy]phenyl-κ C1}chlorido(dimethyl sulfoxide-κ S)platinum(II), [Pt(C14H17O4)Cl(C2H6OS)]. The crystal structures confirm that acetonitrile interacts with the PtII atom via its N atom, while for DMSO, the S atom is the coordinating atom. For the replacement, the longest of the two Pt-Cl bonds is cleaved, leading to a cis position of the solvent ligand with respect to the allyl group. The crystal packing of the complexes is characterized by dimer formation via C-H...O and C-H...π interactions, but no π-π interactions are observed despite the presence of the aromatic ring. [ABSTRACT FROM AUTHOR]

Motivation: With the rapid increase of the structural data of biomolecular complexes, novel structural analysis methods have to be devised with high-throughput capacity to handle immense data input and to construct massive networks at the minimal computational cost. Moreover, novel methods should be capable of handling a broad range of molecular structural sizes and chemical natures, cognisant of the conformational and electrostatic bases of molecular recognition, and sufficiently accurate to enable contextually relevant biological inferences. Results: A novel molecular topology comparison method was developed and tested. The method was tested for both ligand and binding pocket similarity analyses and a PDB-wide ligand topological similarity map was computed. Conclusion: The unprecedentedly wide scope of ligand definition and large-scale topological similarity mapping can provide very robust tools, of performance unmatched by the present alignment-based methods. The method remarkably shows potential for application for scaffold hopping purposes. It also opens new frontiers in the areas of ligand-mediated protein connectivity, ligand-based molecular phylogeny, target fishing, and off-target predictions. [ABSTRACT FROM AUTHOR]

Designed as a multivalent hydrogen bond acceptor, new receptors, Discopus 1a,b, were built from a triphenylene core surrounded by six (diaryl)phosphinate groups. An efficient synthesis was developed to prepare these elaborated structures in a high overall yield. The X-ray structure of receptor 1b showed strong cooperative hydrogen bonds with two water molecules and intermolecular CH-π contacts. In chloroform, Discopus la,b displayed recognition properties toward dihydroxybenzenes, selectively forming complexes with catechol derivatives 4a-c in a 1:2 (host:guest) stoichiometry. According to NMR and microcalorimetry titrations, association constants were found in the 30-2837 M-1 range, which were larger than those reported for curvated catechol receptors (14-120 M-1). Interestingly, Discopus present two distinct catechol binding sites. Weak hydrogen bonding between host phosphinates and guest hydroxyl groups was shown by infrared spectroscopy and 31P NMR. Molecular dynamics simulations and recognition experiments suggested that a stronger hydrogen bond assisted by a π-interaction between the Discopus core and one catechol molecule could exist within the 1:2 complex. [ABSTRACT FROM AUTHOR]

Abstract: Imino-quinolyl ligands L1–L5 were synthesized by condensation reactions and obtained in good yields. Reactions of the ligands with either PdCl2(cod) or K2[PtCl4] gave the corresponding palladium(II) and platinum(II) complexes 1–10 also in good yields. All the compounds were characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy. X-ray crystallography was used to confirm the structures of these compounds. Molecular structures of 3 and 5 showed that the ligands coordinate to the metal center through the two nitrogen atoms, generating a distorted square planar geometry around the palladium atom. The new complexes exhibited remarkable cytotoxic activities against MCF-7 and HT-29 cancer cell lines. [Copyright &y& Elsevier]

The title compound, [AuIII(C9H10NO2)2][AuIIICl4], contains [AuIII(C9H10NO2)2]+ cations and [AuIIICl4]− anions with each of the gold(III) ions in a typical four-coordinate square-planar geometry. Both gold(III) metal centers are located on inversion centers. [ABSTRACT FROM AUTHOR]

Abstract: The complex formed by the reaction of the uranyl ion, UO2 2+, with bromide ions in the ionic liquids 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Bmim][Tf2N]) and methyl-tributylammonium bis(trifluoromethylsulfonyl)imide ([MeBu3N][Tf2N]) has been investigated by UV–Vis and U LIII-edge EXAFS spectroscopy and compared to the crystal structure of [Bmim]2[UO2Br4]. The solid state reveals a classical tetragonal bipyramid geometry for [UO2Br4]2− with hydrogen bonds between the Bmim+ and the coordinated bromides. The UV–Vis spectroscopy reveals the quantitative formation of [UO2Br4]2− when a stoichiometric amount of bromide ions is added to UO2(CF3SO3)2 in both Tf2N-based ionic liquids. The absorption spectrum also suggests a D4h symmetry for [UO2Br4]2− in ionic liquids, as previously observed for the [UO2Cl4]2− congener. EXAFS analysis supports this conclusion and demonstrates that the [UO2Br4]2− coordination polyhedron is maintained in the ionic liquids without any coordinating solvent or water molecules. The mean U–O and U–Br distances in the solutions, determined by EXAFS, are, respectively, 1.766(2) and 2.821(2)Å in [Bmim][Tf2N], and, respectively, 1.768(2) and 2.827(2)Å, in [MeBu3N][Tf2N]. Similar results are obtained in both ionic liquids indicating no significant influence of the ionic liquid cation either on the complexation reaction or on the structure of the uranyl species. [Copyright &y& Elsevier]

The reduction of cyclic bistetrasulfide (II) and a subsequent oxidation of intermediate thiolate with air gives rise to cyclic compound (III) bearing disulfide bridges. [ABSTRACT FROM AUTHOR]

The mol­ecular structure of the title compound, C12H11NO4, at 100 (2) K is characterized by a planar indole ring system, containing a long C—C bond in the 1,2-diketone unit. [ABSTRACT FROM AUTHOR]