An orthorhombic polymorph of 2-(1,3,5-dithiazinan-5-yl)ethanol or MEA-dithiazine

Substituted triazines are a class of compounds utilized for scavenging and sequestering hydrogen sulfide in oil and gas production operations. The reaction of one of these triazines under field conditions resulted in the formation of the title compound, 2-(1,3,5-dithiazinan-5-yl)ethanol, C5H11NOS2, or MEA-dithiazine. Polymorphic form I, in space group I41/a, was first reported in 2004 and its extended structure displays one-dimensional, helical strands connected through O—H...O hydrogen bonds. We describe here the form II polymorph of the title compound, which crystallizes in the orthorhombic space group Pbca as centrosymmetric dimers through pairwise O—H...N hydrogen bonds from the hydroxyl moiety to the nitrogen atom of an adjacent molecule.

Crystal structure and Hirshfeld surface analysis of 6-((E)-2-{4-[2-(4-chlorophenyl)-2-oxoethoxy]phenyl}ethenyl)-4,5-dihydropyridazin-3(2H)-one

The pyridazine ring in the title compound, C20H17ClN2O3, adopts a screw-boat conformation. The whole molecule is flattened, the dihedral angles subtended by the least-squares plane of the central aromatic ring with those of the terminal benzene and pyridazine rings being 15.18 (19) and 11.23 (19)°, respectively. In the crystal, the molecules are linked by pairs of N—H...O bonds into centrosymmetric dimers and by C—H...π contacts into columns. The results of the Hirshfeld surface analysis show that the most prominent interactions are H...H, accounting for 36.5% of overall crystal packing, and H...O/O...H (18.6% contribution) contacts.

SYNTHESIS, CRYSTAL STRUCTURE, HIRSHFELD SURFACE ANALYSIS AND QUANTUM CHEMICAL CALCULATIONS OF [Cu2(C6H9N3S)2(ClO4)2] π-COMPLEX WITH 2-ALLYLAMINO-5-METHYL-1,3,4-THIADIAZOLE

This work is focused on the synthesis and structure characterization of the novel Cu(I) π-complex [Cu2(Thiaz1)2(ClO4)2] (1) with 2-allylamino-5-methyl-1,3,4-thiadiazole (Thiaz1) ligand. The crystals of the compound were obtained by means of the alternating-current electrochemical technique and studied using single crystal X-ray diffraction. The crystal structure of the complex 1 is constructed from the centrosymmetric dimers, in which two copper(I) ions are coordinated by two Thiaz1 molecules through thiadiazole N atoms and allylic C=C bond. Energy framework computational analysis for structure 1 has been performed.

Crystal structure of 4-(anthracen-9-yl)pyridine

The title compound, C19H13N, which crystallizes in the monoclinic C2/c space group with one half-molecule in the asymmetric unit, was synthesized by Suzuki–Miyaura cross-coupling reaction of 9-bromoanthracene with pyridin-4-ylboronic acid and purified by column chromatography on silica gel. Light-yellow crystals of 4-(anthracen-9-yl)-pyridine suitable for X-ray diffraction were collected by the solvent evaporation method. In the crystal, pairs of molecules are connected by intermolecular C—H...π (pyridine) interactions [d(H7...Cg) = 2.7391 (2) Å], forming cyclic centrosymmetric dimers, further resulting in an infinite one-dimensional linear chain along the c-axis direction. Weak face-to-face π–π stacking interactions [d(Cg...Cg) = 3.6061 (2) Å] link neighboring lamellar networks into the supramolecular structure.

Crystal structure and Hirshfeld surface analysis of 6-amino-8-phenyl-1,3,4,8-tetrahydro-2H-pyrido[1,2-a]pyrimidine-7,9-dicarbonitrile

In the title compound, C16H15N5, the 1,4-dihydropyridine ring has a shallow boat conformation, while the 1,3-diazinane ring adopts an envelope conformation. In the crystal, pairwise N—H...N hydrogen bonds generate centrosymmetric dimers featuring R 2 2(12) motifs and C—H...N contacts connect these dimers to form double layers lying parallel to (001). Weak C—H...π and N—H...π interactions help to consolidate the double layers and van der Waals interactions occur between layers. A Hirshfeld surface analysis indicates that the most significant contributions to the crystal packing are from H...H (38.5%), N...H/H...N (33.3%) and C...H/H...C (27.3%) contacts.

Structural diversity among some dialkyltin(IV) benzoate and related derivatives

The molecular structures of five diorganotin(IV) carboxylates, (I)–(V), can be categorized into two main well-known structural types for such Sn complexes. One is the mononuclear dialkytin(IV) carboxylates with an [R2Sn(LH)2]-type skew-trapezoidal bipyramid, where the alkyl ligands are in pseudo-axial positions and the O atoms from two asymmetrically coordinated bidentate carboxylate ligands are in the equatorial plane. This structure type is adopted by dibutylbis{(E)-2-hydroxy-5-[(3-methylphenyl)diazenyl]benzoato}tin(IV) cyclohexane hemisolvate, [Sn(C4H9)2(C14H11N2O3)2]·0.5C6H12, (I), dibenzylbis{(E)-5-[(4-bromophenyl)diazenyl]-2-hydroxybenzoato}tin(IV), [Sn(C7H7)2(C13H8BrN2O3)2], (II), and aquadibenzylbis(4-{(E)-[(Z)-4-hydroxypent-3-en-2-ylidene]amino}benzoato)tin(IV) benzene disolvate, [Sn(C7H7)2(C12H12NO3)2(H2O)]·2C6H6, (III), although the latter has an additional water ligand to give a distorted pentagonal bipyramidal coordination geometry in which the carboxylate groups are more symmetrically coordinated to the Sn atom than in (I) and (II). The other structure motif is that of the tetranuclear bis(dicarboxylatotetraorganodistannoxanes), {[R2Sn(LH)]2O}2, which contain an Sn4O2 core decorated with four bridging carboxylate ligands, plus two alkyl ligands at each SnIV centre. The complexes octabutyltetrakis{μ-(E)-4-[(4-hydroxy-3,5-dimethylphenyl)diazenyl]benzoato}di-μ3-oxido-tetratin(IV) ethanol disolvate, [Sn4(C4H9)8(C15H13N2O3)4O2]·2C2H6O, (IV), and octabutyltetrakis{(E)-3-[(2-hydroxybenzylidene)amino]propanoato}di-μ3-oxido-tetratin(IV), [Sn4(C4H9)8(C10H10NO3)4O2], (V), display this motif. The structures obtained correlate with the 1:1 and 1:2 stoichiometric ratios of the dialkyltin(IV) and carboxylic acid starting materials in the syntheses. The supramolecular structures arising from consideration of secondary Sn...O interactions and/or classic hydrogen bonds include discrete molecules for (V), centrosymmetric dimers for (I), extended chains for (II) and (III), and sheets for (IV).

Reduced 3,4′-bipyrazoles carrying thiophene and thiazole substituents: structures of two intermediates and two products

Cycloaddition reactions between 3-(5-aryloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-1-(thiophen-2-yl)prop-2-en-1-ones and thiosemicarbazide leads to the formation of reduced 3,4′-bipyrazole-2-carbothioamides. Further cycloaddition of these intermediates with either diethyl acetylenedicarboxylate or 4-bromophenacyl bromide leads to reduced 3,4′-bipyrazoles carrying oxothiazole or thiazole substituents, respectively. The structures of two representative intermediates and two representative products established unambiguously the regiochemistry of the cycloaddition reactions. The molecules of 3′-methyl-5′-(2-methylphenoxy)-1′-phenyl-5-(thiophen-2-yl)-3,4-dihydro-1′H,2H-3,4′-bipyrazole-2-carbothioamide, C25H23N5OS2 (Ia), are linked by N—H...N hydrogen bonds to form simple C(8) chains. The analogous compound 5′-(2,4-dichlorophenoxy)-3′-methyl-1′-phenyl-5-(thiophen-2-yl)-3,4-dihydro-1′H,2H-3,4′-bipyrazole-2-carbothioamide hemihydrate crystallizes as a hemihydrate, C24H19Cl2N5OS2·0.5H2O (Ib), and the independent components are linked into a chain of spiro-fused R 4 4(20) rings by a combination of O—H...N and N—H...O hydrogen bonds. In the structure of ethyl (Z)-2-{2-[3′-methyl-1′-phenyl-5-(thiophen-2-yl)-5′-(2-methylphenoxy)-3,4-dihydro-1′H,2H-3,4′-bipyrazole-2-yl]-4-oxo-4,5-dihydrothiazol-5-ylidene}acetate, C31H27N5O4S2 (II), inversion-related pairs of molecules are linked by paired C—H...π(arene) hydrogen bonds to form cyclic centrosymmetric dimers, but there are no direction-specific intermolecular interactions in 4-(4-bromophenyl)-2-[5′-(2,4-dichlorophenoxy)-3′-methyl-1′-phenyl-5-(thiophen-2-yl)-3,4-dihydro-1′H,2H-3,4′-bipyrazole-2-yl]-4-thiazole, C32H22BrCl2N5OS2 (III). Comparisons are made with the structures of some related compounds.

Crystal structure of 2-[(E)-2-(4-bromophenyl)diazen-1-yl]-4,5-bis(4-methoxyphenyl)-1H-imidazole: the first example of a structurally characterized triarylazoimidazole

The title compound, C23H19BrN4O2, is a product of an azo coupling reaction between 3,4-bis(4-methoxyphenyl)imidazole and 4-bromophenyldiazonium tetrafluoroborate. Its crystal structure was determined using data collected at 120 K. The molecule adopts a trans configuration with respect to the N=N double bond. The imidazole and aryl rings attached to the azo linkage are coplanar within 12.73 (14)°, which indicates significant electron delocalization within the molecule. In the crystal, the molecules form centrosymmetric dimers via pairs of N—H...O hydrogen bonds.

1-{3-[(7-Fluoro-9H-pyrimido[4,5-b]indol-4-yl)(methyl)amino]piperidin-1-yl}propan-1-one

The title compound, C19H22FN5O, has been synthesized as an inhibitor of glycogen synthase kinase-3β. Two molecules interact via two N—H...N hydrogen bonds, forming centrosymmetric dimers.

A copper complex of an unusual hydroxy–carboxylate ligand: [Cu(bpy)(C4H4O6)]

A copper(II) complex, (2,2′-bipyridine-κ2 N,N′)[2-hydroxy-2-(hydroxymethyl-κO)propanedioato-κ2 O 1,O 3]copper(II), [Cu(C4H4O6)(C10H8N2)], containing the unusual anionic chelating ligand 2-(hydroxymethyl)tartronate, has been synthesized. [Cu(bpy)2(NO3)](NO3) was mixed with ascorbic acid and Dabco (1,4-diazabicyclo[2.2.2]octane) in DMF (dimethylformamide) solution in the presence of air to produce the title compound. The structure consists of square-pyramidal complexes that are joined by Cu...O contacts [2.703 (2) Å] into centrosymmetric dimers. The C4H4O6 2− ligand, which occupies three coordination sites at Cu, has previously been identified as an oxidation product of ascorbate ion.