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The title compound, [Fe(C2N3)2(C8H7N5)2]·2H2O, has been synthesized solvothermally and characterized by single-crystal X-ray diffraction. The octahedral iron coordination polyhedron contains two di(pyrimidin-2-yl)amine ligands coordinated in a bidentate fashion, and two monodentate dicyanimido ligands, each coordinated via a terminal N atom, with the latter in a cis orientation. The ligand configuration about the iron atom is chiral, although the compound crystallizes as a racemic mixture: the Fe—N distances (> 2.07 Å) are characteristic of high-spin iron(II). In the crystal, an extensive series of N—H...N, O—H...N and O—H...O hydrogen bonds links the independent molecular components into a three-dimensional framework. The H atoms of both water molecules are disordered. The structure also features some π–π and anion–π interactions. The intermolecular interactions were investigated by Hirshfeld surface analysis and two-dimensional fingerprint plots. Comparisons are made with some related compounds.

The low (90 K) and room (298 K) temperature crystal structures of topiramate azidosulfate [systematic name 2,3:4,5-bis-O-(1-methylethylidene)-β-d-fructopyranose azidosulfate], C12H19N3O8S, an intermediate in the synthesis of the anti-convulsant drug topiramate, are described. Topiramate azidosulfate (I) finds use as a reference impurity standard for topiramate. A modified synthesis and some spectroscopic details are also presented.

Co-crystallization of N-(4-methoxyphenyl)piperazine with 4-methylbenzoic acid and with benzene-1,2-dicarboxylic acid yields the salts 4-(4-methoxyphenyl)piperazin-1-ium 4-methylbenzoate monohydrate, C11H17N2O+·C8H7O2−·H2O (I), and bis[4-(4-methoxyphenyl)piperazin-1-ium] benzene-1,2-dicarboxylate, 2C11H17N2O+·C8H4O42− (II). These salts both crystallize with Z′ = 2, in space groups P\overline{1} and Pna21, respectively. In compound (I), a combination of four O—H...O, four N—H...O, one C—H...O and one C—H...π(arene) hydrogen bonds link the six independent components into complex sheets, within which the two piperazine rings, the two anions, and the two water molecules are related by an approximate, non-crystallographic translation along the b-axis direction. In compound (II), sheets containing R44(18) and R1012(38) rings are formed by the combined action of eight independent N—H...O hydrogen bonds. Comparisons are made with the structures of some related compounds.

Crystal structures are reported for two molecular salts containing the 4-(4-nitrophenyl)piperazin-1-ium cation. Co-crystallization from methanol/ethyl acetate solution of N-(4-nitrophenyl)piperazine with benzoic acid gives the benzoate salt, which crystallizes as a monohydrate, C10H14N3O2·C7H5O2·H2O, (I), and similar co-crystallization with 3,5-dinitrosalicylic acid yields the 2-carboxy-4,6-dinitrophenolate salt, C10H14N3O2·C7H3N2O7, (II). In the structure of (I), a combination of O—H...O, N—H...O and C—H...O hydrogen bonds links the components into sheets, while in the structure of (II), the supramolecular assembly, generated by hydrogen bonds of the same types as in (I), is three dimensional. Comparisons are made with the structures of some related compounds.

Crystal structures are reported for three amides containing N-benzo[d]thiazole substituents. In N-(benzo[d]thiazol-6-yl)-3-bromobenzamide, C14H9BrN2OS, where the two ring systems are nearly parallel to one another [dihedral angle = 5.8 (2)°], the molecules are linked by N—H...O and C—H...N hydrogen bonds to form ribbons of R33(19) rings, which are linked into sheets by short Br...Br interactions [3.5812 (6) Å]. N-(6-Methoxybenzo[d]thiazol-2-yl)-2-nitrobenzamide, C15H11N3O4S, crystallizes with Z′ = 2 in space group Pna21: the dihedral angles between the ring systems [46.43 (15) and 66.35 (13)°] are significantly different in the independent molecules and a combination of two N—H...N and five C—H...O hydrogen bonds links the molecules into a three-dimensional network. The molecules of 5-cyclopropyl-N-(6-methoxybenzo[d]thiazol-2-yl)isoxazole-3-carboxamide, C15H13N3O3S, exhibit two forms of disorder, in the methoxy group and in the cyclopropylisoxazole unit; symmetry-related pairs of molecules are linked into dimers by pairwise N—H...N hydrogen bonds. Comparisons are made with the structures of some related compounds.

The crystal structures of three benzimidazole esters containing aryl or heterocyclic substituents at position 2 are reported, and all three exhibit disorder of molecular entities. In ethyl 1-methyl-2-[4-(prop-2-ynoxy)phenyl]-1H-benzimidazole-5-carboxylate, C20H18N2O3, (I), the prop-2-yn-1-oxyphenyl unit is disordered over two sets of atomic sites having effectively equal occupancies, 0.506 (5) and 0.494 (5). The propyl substituent in ethyl 1-propyl-2-(pyren-1-yl)-1H-benzimidazole-5-carboxylate, C29H24N2O2, (II), is disordered over two sets of atomic sites having occupancies 0.601 (8) and 0.399 (8), and the ester unit in ethyl 1-methyl-2-(5-chloro-3-methyl-1-phenyl-1H-pyrazol-4-yl)-1H-benzimidazole-5-carboxylate, C21H19ClN4O2 (III), is disordered over two sets of atomic sites having occupancies 0.645 (7) and 0.355 (7). In each of the C—H...π(arene) hydrogen bonds in (I), the donor and acceptor form parts of different disorder components, so that no continuous aggregation is possible. The molecules of (II) are linked by a single C—H...O hydrogen bond into C(10) chains, which are linked into sheets by a π–π stacking interaction, whereas those of (III) are just linked into C(13) chains, again by a single C—H...O hydrogen bond. Comparisons are made with the structures of some related compounds.

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 R44(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.

Fifteen 4-(2-methoxyphenyl)piperazin-1-ium salts containing organic anions have been prepared and structurally characterized. In the isostructural 4-chlorobenzoate and 4-bromobenzoate salts, C11H17N2O+·C7H4ClO2− (I) and C11H17N2O+·C7H4BrO2− (II), and the 4-iodobenzoate salt C11H17N2O+·C7H4IO2− (III), the ions are linked by N—H...O hydrogen bonds, forming centrosymmetric R44(12) four-ion aggregates; a similar aggregate is formed in the 2-chlorobenzoate salt (V), isomeric with (I). In the 2-fluorobenzoate salt C11H17N2O+·C7H4FO2− (IV), and the isomorphous pair of salts, the 2-bromobenzoate (VI), isomeric with (II) and 2-iodobenzoate (VII), isomeric with (III), N—H...O and C—H...π(arene) interactions link the components into three-dimensional arrays. Four-ion R44(12) aggregates are also found in the 2-methylbenzoate, 4-aminobenzoate and 4-nitrobenzoate salts, C11H17N2O+·C8H7O2− (VIII), C11H17N2O+·C7H6NO2− (IX) and C11H17N2O+·C7H4NO4− (X), but those in (IX) are linked into complex sheets by an additional N—H...O hydrogen bond. In the 3,5-dinitrobenzoate salt, C11H17N2O+·C7H3N2O6−·2H2O (XI), N—H...O and O—H...O hydrogen bonds link the components into a complex ribbon structure. In the picrate salt, C11H17N2O+·C6H2N3O7− (XII), the four-ion aggregates are linked into chains of rings by C—H...O hydrogen bonds. In the hydrogen maleate salt, C11H17N2O+·C4H3O4− (XIII), two- and three-centre hydrogen bonds link the ions into a ribbon structure while both anions contain very short but asymmetric O—H...O hydrogen bonds, having O...O distances of 2.4447 (16) and 2.4707 (17) Å. O—H...O Hydrogen bonds link the anions in the hydrogen fumarate salt (XIV), isomeric with (XIII), into chains that are linked into sheets via N—H...O hydrogen bonds. In the hydrogen (2R,3R)-tartrate salt, C11H17N2O+·C4H5O6−·1.698H2O (XV), the anions are linked into sheets by O—H...O hydrogen bonds. Comparisons are made with the structures of some related compounds.

Two new substituted propanedioate esters have been synthesized using a three-component solvent-free thermal reaction between diethyl propanedioate (diethyl malonate), 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde and an aryl azide, forming two new C—C bonds in a single step. The products diethyl (RS)-2-[(4-bromophenyl)(5-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)methyl]propanedioate, C24H25BrN2O5 (I), and diethyl (RS)-2-[(4-chlorophenyl)(5-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)methyl]propanedioate, C24H25ClN2O5 (II), are isomorphous, with Z′ = 2 in space group P21/n. The two independent molecules in compound (I) are both fully ordered, while each of the independent molecules in compound (II) is disordered, but in different ways. In one molecule of (II), the N-phenyl ring is disordered over two sets of atomic sites having occupancies 0.635 (10) and 0.365 (10), and in the other molecule the ester function is disordered over two sets of atomic sites having occupancies 0.690 (5) and 0.310 (5). In both structures, the two independent molecules adopt different conformations and, in each structure, the molecules are linked into complex sheets by a combination of N—H...O, C—H...O and C—H...π(arene) hydrogen bonds. Comparisons are made with some related structures.

In the title salt {systematic name: 4-[6-chloro-2,9-diazatricyclo[9.4.0.03,8]pentadeca-1(15),3(8),4,6,9,11,13-heptaen-10-yl]-1-methylpiperazin-1-ium 3,5-dinitrobenzoate–3,5-dinitrobenzic acid (1/1)}, C18H20ClN4+·C7H3N2O6−·C7H4N2O6, there is a very short, asymmetric, O—H...O hydrogen bond [O...O = 2.453 (3) Å] within the anion. The oxygen atoms of one of the nitro groups of the anion are disordered over two sets of sites having occupancies of 0.56 (3) and 0.44 (3). The fused tricyclic portion of the cation adopts a butterfly conformation, with a dihedral angle of 45.59 (6)° between the planes of the two aryl rings. In the crystal, a combination of O—H...O, N—H...O and C—H...O hydrogen bonds links the component species into a three-dimensional framework. Comparisons are made with the structures of some related compounds.

The structures are reported for five salts formed by reactions between N-(4-fluorophenyl)piperazine and aromatic acids. In 4-(4-fluorophenyl)piperazin-1-ium 2-fluorobenzoate monohydrate, C10H14FN2+·C7H4FO2−·H2O, (I), the components are linked by a combination of N—H...O and O—H...O hydrogen bonds to form a chain of alternating R46(12) and R66(16) rings. The ionic components of 4-(4-fluorophenyl)piperazin-1-ium 2-bromobenzoate 0.353-hydrate, C10H14FN2+·C7H4BrO2−·0.353H2O, (II), are linked by N—H...O hydrogen bonds to form a centrosymmetric four-ion aggregate containing an R44(12) motif, and these aggregates are linked into a molecular ladder by a single C—H...π(arene) hydrogen bond. 4-(4-Fluorophenyl)piperazin-1-ium 2-iodobenzoate, C10H14FN2+·C7H4IO2−, (III), crystallizes with Z′ = 2 in space group P\overline{1}: the four independent ions are linked by N—H...O hydrogen bonds to form a non-centrosymmetric aggregate again containing an R44(12) motif, and aggregates of this type are linked into a ribbon by a combination of C—H...O and C—H...π(arene) hydrogen bonds. The anion in 4-(4-fluorophenyl)piperazin-1-ium 2,4,6-trinitrophenolate, C10H14FN2+·C6H2N3O7−, (IV), shows clear evidence of extensive electronic delocalization from the phenolate O atom into the adjacent ring. The ions are linked by a combination of two-centre N—H...O and three-centre N—H...(O)2 hydrogen bonds to form centrosymmetric four-ion aggregates containing three types of ring. The ions in 4-(4-fluorophenyl)piperazin-1-ium 3,5-dinitrobenzoate, C10H14FN2+·C7H3N2O6−, (V), are again linked by N—H...O hydrogen bonds to form centrosymmetric R44(12) aggregates, which are themselves linked by a C—H...π(arene) hydrogen bond to form sheets, the stacking of which leads to the formation of narrow channels, containing disordered and/or mobile solvent entities. Comparisons are made with some related structures.

Two new N-{[4-(3-aryl-4-sydnonylideneamino)-5-sulfanylidene-1H-1,2,4-triazol-3-yl]methyl}benzamides have been prepared by acid-promoted condensation reactions between 3-aryl-4-formylsydnones and N-[(4-amino-5-sulfanylidene-1H-1,2,4-triazol-3-yl)methyl]benzamide, and both have been crystallized as ethanol monosolvates. N-{[4-(3-Phenyl-4-sydnonylideneamino)-5-sulfanylidene-1H-1,2,4-triazol-3-yl]methyl}benzamide ethanol monosolvate, C19H15N7O3S·C2H6O (I), and N-({4-[3-(4-methylphenyl)-4-sydnonylideneamino]-5-sulfanylidene-1H-1,2,4-triazol-3-yl}methyl)benzamide ethanol monosolvate, C20H17N7O3S·C2H6O (II), differ only in the presence of a methyl group for (II) instead of a hydrogen atom for (I), and in both of them the ethanol component is disordered over two sets of atomic sites having occupancies of 0.836 (6) and 0.164 (6) in (I), and 0.906 (6) and 0.094 (6) in (II). Combinations of O—H...O and N—H...O hydrogen bonds link the molecules into cyclic, centrosymmetric four-molecule aggregates. Comparisons are made with the structures of some related compounds.

Three salts containing the 4-(4-fluorophenyl)piperazin-1-ium cation have been prepared and structurally characterized. In 4-(4-fluorophenyl)piperazin-1-ium 2-hydroxy-3,5-dinitrobenzoate, C10H14FN2+·C7H3N2O7−, (I), the anion contains an intramolecular O—H...O hydrogen bond, and it has a structure similar to that of the picrate ion. The cations and anions are linked into [001] chains of rings by a combination of two three-centre N—H...(O)2 hydrogen bonds. The anion in 4-(4-fluorophenyl)piperazin-1-ium hydrogen oxalate, C10H14FN2+·C2HO4−, (II), is planar, and the cations and anions are linked into (100) sheets by multiple hydrogen bonds including two-centre N—H...O, three-centre N—H...(O)2, O—H...O, C—H...O and C—H...π(arene) types. In 4-(4-fluorophenyl)piperazin-1-ium hydrogen (2R,3R)-tartrate monohydrate, C10H14FN2+·C4H5O6−·H2O, (III), the anion exhibits an approximate non-crystallographic twofold rotation symmetry with antiperiplanar carboxyl groups. A combination of eight hydrogen bonds, encompassing two- and three-centre N—H...O systems, O—H...O and C—H...π(arene) types, link the independent components into a three-dimensional framework. Comparisons are made with some related structures.

Five examples each of 3-(5-aryloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-1-[4-(prop-2-yn-1-yloxy)phenyl]prop-2-en-1-ones and the corresponding 1-(4-azidophenyl)-3-(5-aryloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)prop-2-en-1-ones have been synthesized in a highly efficient manner, starting from a common source precursor, and structures have been determined for three examples of each type. In each of 3-[5-(2-chlorophenoxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl]-1-[4-(prop-2-yn-1-yloxy)phenyl]prop-2-en-1-one, C28H21ClN2O3, (Ib), the isomeric 3-[5-(2-chlorophenoxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl]-1-[4-(prop-2-yn-1-yloxy)phenyl]prop-2-en-1-one, (Ic), and 3-[3-methyl-5-(naphthalen-2-yloxy)-1-phenyl-1H-pyrazol-4-yl]-1-[4-(prop-2-ynyloxy)phenyl]prop-2-en-1-one, C32H24N2O3, (Ie), the molecules are linked into chains of rings, formed by two independent C—H...O hydrogen bonds in (Ib) and by a combination of C—H...O and C—H...π(arene) hydrogen bonds in each of (Ic) and (Ie). There are no direction-specific intermolecular interactions in the structure of 1-(4-azidophenyl)-3-[3-methyl-5-(2-methylphenoxy)-1-phenyl-1H-pyrazol-4-yl]prop-2-en-1-one, C26H21N5O2, (IIa). In 1-(4-azidophenyl)-3-[5-(2,4-dichlorophenoxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl]prop-2-en-1-one, C25H17Cl2N5O2, (IId), the dichlorophenyl group is disordered over two sets of atomic sites having occupancies 0.55 (4) and 0.45 (4), and the molecules are linked by a single C—H...O hydrogen bond to form cyclic, centrosymmetric R22(20) dimers. Similar dimers are formed in 1-(4-azidophenyl)-3-[3-methyl-5-(naphthalen-2-yloxy)-1-phenyl-1H-pyrazol-4-yl]prop-2-en-1-one, C29H21N5O2, (IIe), but here the dimers are linked into a chain of rings by two independent C—H..π(arene) hydrogen bonds. Comparisons are made between the molecular conformations within both series of compounds.

Crystal structures are reported for N-(4-methoxyphenyl)piperazine (MeOPP), (I), and for its 3,5-dinitrobenzoate, 2,4,6-trinitrophenolate (picrate) and 4-aminobenzoate salts, (II)–(IV), the last of which crystallizes as a monohydrate. In MeOPP, C11H16N2O, (I), the 4-methoxyphenyl group is nearly planar and it occupies an equatorial site on the piperazine ring: the molecules are linked into simple C(10) chains by N—H...O hydrogen bonds. In each of the salts, i.e., C11H17N2O+·C7H3N2O6−, (II), C11H17N2O+·C6H2N3O7−, (III), and C11H17N2O+·C7H6NO2−·H2O, (IV), the effectively planar 4-methoxyphenyl substituent again occupies an equatorial site on the piperazine ring. In (II), two of the nitro groups are disordered over two sets of atomic sites and the bond distances in the anion indicate considerable delocalization of the negative charge over the C atoms of the ring. The ions in (II) are linked by two N—H...O hydrogen bonds to form a cyclic, centrosymmetric four-ion aggregate; those in (III) are linked by a combination of N—H...O and C—H...π(arene) hydrogen bonds to form sheets; and the components of (IV) are linked by N—H...O, O—H...O and C—H...π(arene) hydrogen bonds to form a three-dimensional framework structure. Comparisons are made with the structures of some related compounds.

Chalcones of type 4-XC6H4C(O)CH=CHC6H4(OCH2CCH)-4, where X = Cl, Br or MeO, have been converted to the corresponding 4,5-dihydropyrazole-1-carbothioamides using a cyclocondensation reaction with thiosemicarbazide. The chalcones 1-(4-chlorophenyl)-3-[4-(prop-2-ynyloxy)phenyl]prop-2-en-1-one, C18H13ClO2, (I), and 1-(4-bromophenyl)-3-[4-(prop-2-ynyloxy)phenyl]prop-2-en-1-one, C18H13BrO2, (II), are isomorphous, and their molecules are linked into sheets by two independent C—H...π(arene) interactions, both involving the same aryl ring with one C—H donor approaching each face. In each of the products (RS)-3-(4-chlorophenyl)-5-[4-(prop-2-ynyloxy)phenyl]-4,5-dihydropyrazole-1-carbothioamide, C19H16ClN3OS, (IV), (RS)-3-(4-bromophenyl)-5-[4-(prop-2-ynyloxy)phenyl]-4,5-dihydropyrazole-1-carbothioamide, C19H16BrN3OS, (V), and (RS)-3-(4-methoxyphenyl)-5-[4-(prop-2-ynyloxy)phenyl]-4,5-dihydropyrazole-1-carbothioamide, C20H19N3O2S, (VI), the reduced pyrazole ring adopts an envelope conformation with the C atom bearing the 4-prop-2-ynyloxy)phenyl substituent, which occupies the axial site, displaced from the plane of the four ring atoms. Compounds (IV) and (V) are isomorphous and their molecules are linked into chains of edge-fused rings by a combination of N—H...S and C—H...S hydrogen bonds. The molecules of (VI) are linked into sheets by a combination of N—H...S, N—H...N and C—H...π(arene) hydrogen bonds. Comparisons are made with the structures of some related compounds.

Two new chalcones containing both pyrazole and thiophene substituents have been prepared and structurally characterized. 3-(3-Methyl-5-phenoxy-1-phenyl-1H-pyrazol-4-yl)-1-(thiophen-2-yl)prop-2-en-1-one, C23H18N2O2S (I), and 3-[3-methyl-5-(2-methylphenoxy)-1-phenyl-1H-pyrazol-4-yl]-1-(thiophen-2-yl)prop-2-en-1-one, C24H20N2O2S (II), are isomorphous as well as isostructural, and in each the thiophene substituent is disordered over two sets of atomic sites having occupancies 0.844 (3) and 0.156 (3) in (I), and 0.883 (2) and 0.117 (2) in (II). In each structure, the molecules are linked into sheets by a combination of C—H...N and C—H...O hydrogen bonds. Comparisons are made with some related compounds.

Three title compounds, namely, 2-(4-chlorobenzyl)-5-[(1H-indol-3-yl)methyl]-6-phenylimidazo[2,1-b][1,3,4]thiadiazole, C26H19ClN4S, (I), 2-(4-chlorobenzyl)-6-(4-fluorophenyl)-5-[(1H-indol-3-yl)methyl]imidazo[2,1-b][1,3,4]thiadiazole, C26H18ClFN4S, (II), and 6-(4-bromophenyl)-2-(4-chlorobenzyl)-5-[(1H-indol-3-yl)methyl]imidazo[2,1-b][1,3,4]thiadiazole, C26H18BrClN4S, (III), have been prepared using a reductive condensation of indole with the corresponding 6-aryl-2-(4-chlorobenzyl)imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehydes (aryl = phenyl, 4-fluorophenyl or 4-bromophenyl), and their crystal structures have been determined. The asymmetric unit of compound (I) consists of two independent molecules and one of the molecules exhibits disorder of the 4-chlorobenzyl substituent with occupancies 0.6289 (17) and 0.3711 (17). Each type of molecule forms a C(8) chain motif built from N—H...N hydrogen bonds, which for the fully ordered molecule is reinforced by C—H...π interactions. In compound (II), the chlorobenzyl unit is again disordered, with occupancies 0.822 (6) and 0.178 (6), and the molecules form C(8) chains similar to those in (I), reinforced by C—H...π interactions involving only the major disorder component. The chlorobenzyl unit in compound (III) is also disordered with occupancies of 0.839 (5) and 0.161 (5). The molecules are linked by a combination of one N—H...N hydrogen bond and four C—H...π interactions, forming a three-dimensional framework.

In the title compound, [CdNi(C9H8N2)2(CN)4]n, the Cd and Ni atoms both lie on centres of inversion in space group P21/c. The Cd atom is coordinated by two bidentate quinolin-8-amine ligands and by the N atoms of two cyano ligands, while the square planar Ni atom is coordinated by the C atoms of four cyano ligands. These units form a one-dimensional coordination polymer containing an (–NC—Ni—CN—Cd–)n backbone, and the coordination polymer chains are linked into a three-dimensional array by a combination of N—H...N and C—H...N hydrogen bonds, augmented by a π–π stacking interaction.

Twelve 4-(4-methoxyphenyl)piperazin-1-ium salts containing organic anions have been prepared and structurally characterized. The monohydrated benzoate, 4-fluorobenzoate, 4-chlorobenzoate and 4-bromobenzoate salts, C11H17N2O+·C7H5O2−·H2O (I), C11H17N2O+·C7H4FO2−·H2O (II), C11H17N2O+·C7H4ClO2−·H2O (III), and C11H17N2O+·C7H4BrO2−·H2O (IV), respectively, are isomorphous and all exhibit disorder in the 4-methoxyphenyl unit: the components are linked by N—H...O and O—H...O hydrogen bond to form chains of rings. The unsolvated 2-hydroxybenzoate, pyridine-3-carboxylate and 2-hydroxy-3,5-dinitrobenzoate salts, C11H17N2O+·C7H5O3− (V), C11H17N2O+·C6H4NO2− (VI) and C11H17N2O+·C7H3N2O7− (VII), respectively, are all fully ordered: the components of (V) are linked by multiple N—H...O hydrogen bonds to form a chain of rings; those of (VI) are linked into a three-dimensional framework by a combination of N—H...O, C—H...O and C—H...N hydrogen bonds and those of (VII), where the anion has a structure reminiscent of the picrate anion, are linked into a three-dimensional array by N—H...O and C—H...O hydrogen bonds. The hydrogensuccinate and hydrogenfumarate salts, C11H17N2O+·C4H5O4− (VIII) and C11H17N2O+·C4H3O3− (IX), respectively, are isomorphous, and both exhibit disorder in the anionic component: N—H...O and O—H...O hydrogen bonds link the ions into sheets, which are further linked by C—H...π(arene) interactions. The anion of the hydrogenmaleate salt, C11H17N2O+·C4H3O3− (X), contains a very short and nearly symmetrical O...H...O hydrogen bond, and N—H...O hydrogen bonds link the anions into chains of rings. The ions in the trichloroacetate salt, C11H17N2O+·C2Cl3O2− (XI), are linked into simple chains by N—H...O hydrogen bonds. In the hydrated chloranilate salt, 2C11H17N2O+·C6Cl2O42−·2H2O (XII), which crystallizes as a non-merohedral twin, the anion lies across a centre of inversion in space group P21/n, and a combination of N—H...O and O—H...O hydrogen bonds generates complex sheets. Comparisons are made with the structures of some related compounds.

Six new 1-aroyl-4-(4-methoxyphenyl)piperazines have been prepared, using coupling reactions between benzoic acids and N-(4-methoxyphenyl)piperazine. There are no significant hydrogen bonds in the structure of 1-benzoyl-4-(4-methoxyphenyl)piperazine, C18H20N2O2, (I). The molecules of 1-(2-fluorobenzoyl)-4-(4-methoxyphenyl)piperazine, C18H19FN2O2, (II), are linked by two C—H...O hydrogen bonds to form chains of rings, which are linked into sheets by an aromatic π–π stacking interaction. 1-(2-Chlorobenzoyl)-4-(4-methoxyphenyl)piperazine, C18H19ClN2O2, (III), 1-(2-bromobenzoyl)-4-(4-methoxyphenyl)piperazine, C18H19BrN2O2, (IV), and 1-(2-iodobenzoyl)-4-(4-methoxyphenyl)piperazine, C18H19IN2O2, (V), are isomorphous, but in (III) the aroyl ring is disordered over two sets of atomic sites having occupancies of 0.942 (2) and 0.058 (2). In each of (III)–(V), a combination of two C—H...π(arene) hydrogen bonds links the molecules into sheets. A single O—H...O hydrogen bond links the molecules of 1-(2-hydroxybenzoyl)-4-(4-methoxyphenyl)piperazine, C18H20N2O3, (VI), into simple chains. Comparisons are made with the structures of some related compounds.

In the title compound, C61H15ClN2O3, the heterocyclic ring adopts an envelope conformation, folded across the N...N line, with the 2,5-dimethoxyphenyl unit occupying a quasi-axial site. There are two N—H...O hydrogen bonds in the structure: one hydrogen bond links molecules related by a 41 screw axis to form a C(6) chain, and the other links inversion-related pairs of molecules to form an R22(8) ring. The ring motif links all of the chains into a continuous three-dimensional framework structure. Comparisons are made with the structures of some related compounds.

In each of the compounds 1-[(1,3-benzodioxol-5-yl)methyl]-4-(3-fluorobenzoyl)piperazine, C19H19FN2O3 (I), 1-[(1,3-benzodioxol-5-yl)methyl]-4-(2,6-difluorobenzoyl)piperazine, C19H18F2N2O3 (II), and 1-[(1,3-benzodioxol-5-yl)methyl]-4-(2,4-dichlorobenzoyl)piperazine, C19H19Cl2N2O3 (III), the piperazine rings adopt a chair conformation with the (1,3-benzodioxol-5-yl)methyl substituent occupying an equatorial site: the five-membered rings are all slightly folded across the O...O line leading to envelope conformations. The dihedral angle between the planar amidic fragment and the haloaryl ring is 62.97 (5)° in (I) but 77.72 (12)° and 75.50 (5)° in (II) and (III), respectively. Despite their similarity in constitution and conformation, the supramolecular interactions in (I)–(III) differ: in (I), a combination of C—H...O and C—H...π(arene) hydrogen bonds links the molecules into a three-dimensional framework structure, but there are no hydrogen bonds of any sort in either (II) or (III), although the structure of (III) contains a short Cl...Cl contact between inversion-related pairs of molecules.

Co-crystallization of racemic 1-cyclohexyl-1-phenyl-3-(piperidin-1-yl)propan-1-ol (trihexyphenidyl) with 3,5-dinitrobenzoic acid gives a simple 1:1 salt, namely 1-(3-cyclohexyl-3-hydroxy-3-phenylpropyl)piperidin-1-ium 3,5-dinitrobenzoate, C20H32NO+·C7H3N2O6−, (I), whereas a similar co-crystallization using (Z)-3-(2-chloro-9H-thioxanthen-9-yl)-N,N-dimethylpropan-1-amine (chlorprothixene) gives a 1:2 acid salt, namely (Z)-3-(2-chloro-9H-thioxanthen-9-yl)-N,N-dimethylpropan-1-aminium hydrogen bis(3,5-dinitrobenzoate), C18H19ClNS+·[H(C7H3N2O6)2]−, (II), the anion of which contains a very short O—H...O hydrogen bond, with dimensions O—H = 1.04 (3) Å, H...O = 1.41 (3) Å, O...O = 2.4197 (15) Å and O—H...O = 161 (3)°. In the cation of (I), the cyclohexyl and piperidyl rings both adopt chair conformations, whereas in the cation of (II), the central heterocyclic ring adopts a boat conformation, so that the dihedral angle between the two aryl rings is 41.56 (4)°. A combination of O—H...O, N—H...O and C—H...O hydrogen bonds links the ions of (I) into a complex chain of rings, and these chains are linked into sheets by π–π stacking interactions between inversion-related pairs of anions. In compound (II), a different combination of O—H...O, N—H...O and C—H...O hydrogen bonds links the ions into sheets. Comparisons are made with some related structures.

In 1-(2-iodobenzoyl)-4-(pyrimidin-2-yl)piperazine, C15H15IN4O, the central piperazine ring adopts an almost perfect chair conformation with the pyrimidine substituent in an equatorial site. The planar amide unit makes a dihedral angle of 80.44 (7)° with the phenyl ring. A combination of C—H...O and C—H...π(arene) hydrogen bonds links the molecules into a complex three-dimensional network structure, augmented by a π–π stacking interaction and an I...N halogen bond, all involving different pairs of inversion-related molecules. Comparisons are made with the structures of a number of related compounds.

Four 1-aryl-1H-pyrazole-3,4-dicarboxylate derivatives, one acid, two esters and a dicarbohydrazide have been synthesized starting from 3-aryl sydnones, and structurally characterized. There is an intramolecular O—H...O hydrogen bond in 1-phenyl-1H-pyrazole-3,4-dicarboxylic acid, C11H8N2O4, (I), and the molecules are linked into a three-dimensional framework structure by a combination of O—H...O, O—H...N, C—H...O and C—H...π(arene) hydrogen bonds. In each of the two esters dimethyl 1-phenyl-1H-pyrazole-3,4-dicarboxylate, C13H12N2O4, (II), and dimethyl 1-(4-methylphenyl)-1H-pyrazole-3,4-dicarboxylate, C14H14N2O4, (III), C—H...O hydrogen bonds lead to the formation of cyclic centrosymmetric dimers: in (III), one of the methoxycarbonyl groups is disordered over two sets of atomic sites having occupancies 0.71 (2) and 0.29 (2). An intramolecular N—H...O hydrogen bond is present in the structure of 1-(4-methoxyphenyl)-1H-pyrazole-3,4-dicarbohydrazide, C12H14N6O3, (IV), and the molecules are linked into a three-dimensional framework structure by a combination of N—H...O, N—H...N, N—H...π(arene) and C—H...O hydrogen bonds. Comparisons are made with the structures of a number of related compounds.

Structures are reported for six closely related salts of tris(bipyridyl)iron(II) cations, namely tris(2,2′-bipyridine)iron(II) bis(1,1,3,3-tetracyano-2-methoxypropenide) 0.776-hydrate, [Fe(C10H8N2)3](C8H3N4O)2.0.776H2O, (I), tris(2,2′-bipyridine)iron(II) 1,1,3,3-tetracyano-2-(propylsulfanyl)propenide perchlorate, [Fe(C10H8N2)3](C10H7N4S)(ClO4), (II), tris(5,5′-dimethyl-2,2′-bipyridine)iron(II) 1,1,3,3-tetracyano-2-methoxypropenide tetrafluoridoborate ethanol 0.926-solvate, [Fe(C12H12N2)3](C8H3N4O)(BF4).0.926C2H2O, (III), tris(5,5′-dimethyl-2,2′-bipyridine)iron(II) 1,1,3,3-tetracyano-2-ethoxypropenide tetrafluoridoborate, [Fe(C12H12N2)3](C9H5N4O)(BF4), (IV), tris(5,5′-dimethyl-2,2′-bipyridine)iron(II) 1,1,3,3-tetracyano-2-(ethylsufanyl)propenide tetrafluoridoborate, [Fe(C12H12N2)3](C9H5N4S)(BF4), (V), and tris(5,5′-dimethyl-2,2′-bipyridine)iron(II) 1,1,3,3-tetracyano-2-propoxypropenide tetrafluoridoborate, [Fe(C12H12N2)3](C10H7N4O)(BF4), (VI). In compound (I), one of the anions is disordered over two sets of atomic sites with equal occupancies while, in the second anion, just one of the C(CN)2 units is disordered, again over two sets of atomic sites with equal occupancies: the anionic components are linked by multiple C—H...N hydrogen bonds to form a three-dimensional framework. In compound (II), the polynitrile anion is disordered over two sets of atomic sites with occupancies in the approximate ratio 3:1, while the perchlorate anion is disordered over three sets of atomic sites: there are C—N...π interactions between the cations and the polynitrile anion. The polynitrile anion in compound (III) is fully ordered, but the tetrafluoridoborate anion is disordered over two sets of atomic sites with occupancies 0.671 (4) and 0.329 (4): the cations and the tetrafluoridoborate anions are linked by C—H...F interactions to form an interrupted chain. Compounds (IV) and (V) are isostructural and all of the ionic components are fully ordered in both of them: the cations and tetrafluoridoborate anions are linked into C22(12) chains. The polynitrile anion in compound (VI) is disordered over two sets of atomic sites with approximately equal occupancies, and here the chains formed by the cations and the tetrafluoridoborate anions are of the C22(13) type.

In the title compound, C18H18N4O6, the piperazine ring adopts a chair conformation, the amidic N atom is planar (sum of angles = 360°) and the non-amidic N atom is pyramidal (343°). There are no hydrogen bonds of any kind in the crystal, but the molecules are linked by two independent π(nitrobenzene)...π(methoxybenzene) stacking interactions to form π-stacked sheets with inter-centroid separations of 3.8444 (12) and 3.9197 (12) Å.

In the title compound, [Fe{(C5H4N)3N}2][C{C(CN)2}3], both ions lie across centres of inversion, with the anion being statistically disordered over two sets of atomic sites having equal occupancy. The cation and anion have approximate \overline{3} and 32 symmetry, respectively, and the Fe—N bond lengths indicate low-spin FeII. A combination of two-centre C—H...N and three-centre C—H...(N)2 hydrogen bonds link the ions into complex sheets. Several low-occupancy water molecules are present, whose H atoms could not be located: accordingly, the reflection data were subjected to the SQUEEZE procedure [Spek (2015). Acta Cryst. C71, 9–18].

In the molecule of the title compound, C15H14N2O2, the 2-ethylphenyl group is disordered over two sets of atomic sites having occupancies of 0.515 (19) and 0.485 (19), and the dihedral angle between the two partial-occupancy aryl rings is 6(2)°. A combination of C—H...O hydrogen bonds and nitro...π(arene) interactions links the molecules into a continuous three-dimensional framework structure. Comparisons are made with the structures of some related compounds.

The redetermination of the structure of the title compound, [Fe(C15H12N4)2](ClO4)2, (I), confirms the structure previously reported [Kucharski et al. (1978a). Aust. J. Chem. 31, 53–56], but models the perchlorate over four sets of atomic sites, rather than using just one set of sites as in the original report. The supramolecular assembly, not reported previously, takes the form of a complex three-dimensional framework built from C—H...O hydrogen bonds. The isotypic nickel(II) analogue, [Ni(C15H12N4)2](ClO4)2, (III), has been refined using the original data set [Wang et al. (2011). Acta Cryst. E67, m78], again using a four-component disorder model for the anion, rather than a two-component model as in the original report, leading to more satisfactory Cl—O distances and O—Cl—O angles.

The molecule of the title compound, C13H10ClNO, (I), which contains an intramolecular O—H...N hydrogen bond, is almost planar: the dihedral angle between the two aryl rings is only 3.31 (9)°. The molecules of (I) are linked into sheets by two C—H...π(arene) hydrogen bonds and the sheets are linked into a three-dimensional structure by O—H...O hydrogen bonds. Comparisons are made with the structures of a number of related compounds.

In the molecules of both (E)-1-{3-[(5-fluoro-2-hydroxybenzylidene)amino]phenyl}ethanone, C15H12FNO2, (I), and (E)-1-{3-[(2-hydroxy-3-methoxybenzylidene)amino]phenyl}ethanone, C16H15NO3, (II), which crystallizes with Z′ = 2 in space group Pca21, there are intramolecular O—H...N hydrogen bonds, and the non-H atoms in each molecule are essentially coplanar. In the crystal of (I), molecules are linked by a single C—H...O hydrogen bond to form a C(8) chain, whereas in the crystal of (II), molecules are linked by three C—H...O hydrogen bonds to form sheets within which orthogonal C22(16) and C22(17) chains can be identified. Comparisons are made with some related structures.

Ebastine, 4-(benzhydryloxy)-1-[4-(4-tert-butylphenyl)-4-oxobutyl]piperidine, reacts with 3,5-dinitrobenzoic acid in methanol solution to give the title 1:1 salt, ebastinium 3,5-dinitrobenzoate, C32H40NO2+·C7H3N2O6−. In the cation, the disubstituted aryl ring exhibits orientational disorder over two sets of atomic sites having occupancies 0.706 (4) and 0.294 (6), with a dihedral angle of 41.2 (5)° between the two orientations: the bulky Ph2CH—O– substituent occupies an axial site on the piperidine ring. The two ions in the selected asymmetric unit are linked by a nearly linear N—H...O hydrogen bond and this, in combination with two C—H...O hydrogen bonds, links the ions into complex sheets.

The N,N-dimethylethylamminium unit in N,N-dimethyl-[2-(2,2-diphenyl)-2-prop-2-ynyloxyacetoxy]ethylamine, C21H23NO3 (I), is disordered over two sets of atomic sites having occupancies of 0.880 (3) and 0. 120 (3), but there are no direction-specific interactions between the molecules of (I). The cation in N,N-dimethyl-[2-(2,2-diphenyl)-2-prop-2-ynyloxyacetoxy]ethylammonium 2,4,6-trinitrophenolate (picrate), C21H24NO3+·C6H2N3O7− (II), shows a similar type of disorder, with occupancies of 0.654 (11) and 0.346 (11), although the overall conformation of the cation in (II) is different from that in the neutral (I). The component ions are are linked by an almost planar three-centre N—H...(O)2 hydrogen bond, and the ion pairs are further linked by a combination of three C—H...O hydrogen bonds to form sheets. Comparisons are made with some related structures.

In both 2-amino-4,4,7,7-tetramethyl-4,5,6,7-tetrahydro-1,3- benzothiazol-3-ium benzoate, C11H19N2S+·C7H5O2−, (I), and 2-amino-4,4,7,7-tetramethyl-4,5,6,7-tetrahydro-1,3-benzothiazol-3-ium picrate (2,4,6-trinitrophenolate), C11H19N2S+·C6H2N3O7−, (II), the cations are conformationally chiral as the six-membered rings adopt half-chair conformations, which are disordered over two sets of atomic sites giving approximately enantiomeric disorder. For both cations, the bond lengths indicate delocalization of the positive charge comparable to that in an amidinium cation. The bond lengths in the picrate anion in (II) are consistent with extensive delocalization of the negative charge into the ring and onto the nitro groups, in two of which the O atoms are disordered over two sets of sites. In (I), the ionic components are linked by N—H...O hydrogen bonds to form a chain of rings, and in (II), the N—H...O hydrogen bonds link the components into centrosymmetric four-ion aggregates containing seven hydrogen bonded rings of four different types.

The hydrated title salt, [Cd2Cl2(C10H8N2)4](C9H5N4O)2·0.81H2O, was obtained from the hydrothermal reaction between 2,2′-bipyridine, cadmium(II) chloride and potassium 1,1,3,3-tetracyano-2-ethoxypropenide. The binuclear cation lies across a centre of inversion in the space group P21/c, with the other components in general positions. The cation has approximate, but non-crystallographic 2/m symmetry and each of the CdII atoms is a stereogenic centre, one having the Δ configuration and the other the Λ configuration. In the anion, one of the C(CN)2 units is disordered over two sets of atomic sites having occupancies 0.75 (2) and 0.25 (2). The cations are linked by two independent C—H...Cl hydrogen bonds to form a sheet of R22(14) and R42(24) rings.

In the crystal of 2-(4-chlorophenyl)-N-(2-iodophenyl)acetamide, C14H11ClINO, molecules are linked by a combination of N—H...O and C—H...O hydrogen bonds to form a C(4)C(4)[R21(7)] chain of rings and chains of this type are linked by a combination of C—Cl...π(arene) and C—I...π(arene) interactions to form deeply puckered twofold interwoven sheets. In the crystal of 2-(4-chlorophenyl)-N-(pyrazin-2-yl)acetamide, C12H10ClN3O, molecules are linked into complex sheets by N—H...N, C—H...N and C—H...O hydrogen bonds, and by C—H...π(arene) interactions.

The title hydrated salt, C30H26N62+·2C9H5N4O−·3H2O, was obtained as an unexpected product from the hydrothermal reaction between potassium 1,1,3,3-tetracyano-2-ethoxypropenide, 4,4′-bipyridine and iron(II) sulfate heptahydrate. The cation lies across a twofold rotation axis in the space group I2/a with the other components all in general positions. In the cation, the H atom linking the pyridine units is disordered over two adjacent sites having occupancies of 0.66 (4) and 0.36 (4), i.e. as N—H...N and N...H—N. The water molecules of crystallization are each disordered over two sets of atomic sites, having occupancies of 0.522 (6) and 0.478 (6) for one, and 0.34 (3) and 0.16 (3) for the other, and it was not possible to reliably locate the H atoms associated with these partial-occupancy sites. In the crystal, four independent C—H...N hydrogen bonds link the ionic components into a three-dimensional network.

In the crystal of compound (I), C14H11ClOS, molecules are linked by C—H...O hydrogen bonds to form simple C(5) chains. Compound (II), C26H22O, crystallizes with Z′ = 2 in space group P-1; one of the molecules is fully ordered but the other is disordered over two sets of atomic sites having occupancies 0.644 (3) and 0.356 (3). The two disordered components differ from one another in the orientation of the isopropyl substituents, and both differ from the ordered molecules in the arrangement of the central propenone spacer unit, so that the crystal of (II) contains three distinct conformers. The ordered and disordered conformers each form a C(8) chain built from a single type of C—H...O hydrogen bond but those formed by the disordered conformers differ from that formed by the ordered form.

In the title compound, C21H17N3O3S, the non-H atoms, apart from those in the benzoyl group, are almost coplanar (r.m.s. deviation = 0.049 Å) and the benzoyl group is almost orthogonal to the plane of the rest of the molecule [dihedral angle = 80.34 (6)°]. In the crystal, a combination of N—H...O and asymmetric bifurcated O—H...(N,O) hydrogen bonds link the molecules into a three-dimensional network. Weak C—H...O interactions are also observed.

The title compound, C19H17Cl3N2O3, has been prepared in a cyclocondensation reaction between 2,3,5-trichlorobenzaldehye and 4-acetyl-2-methyl-1H-imidazole. The cyclohexenone ring adopts an envelope conformation with the C atom substituted by the trichlorophenyl ring as the flap. The mutually trans ester and aryl substituents both occupy equatorial sites. In the crystal, a combination of N—H...O and C—H...N hydrogen bonds links the molecules into ribbons of edge-fused centrosymmetric rings, which enclose R22(14) and R44(16) alternate ring motifs, propagating along the b-axis direction.

In the title racemic compound, C12H10ClNO, the dihedral angle between the benzene and pyridine rings is 74.34 (6)°. In the crystal, the molecules are linked by O—H...N hydrogen bonds, forming zigzag C(5) [001] chains in which alternating R- and S-configuration molecules are related by c-glide symmetry. In addition, inversion-related pairs of molecules are linked into dimers by pairs of weak C—Cl...π(pyridyl) interactions, which link the hydrogen-bonded chains into (100) sheets. Structural comparisons are drawn with a number of related compounds.

The structures of three 3-methyl-1H-1,2,4-triazole-5-thione derivatives are reported. The structure of 4-amino-3-methyl-1H-1,2,4-triazole-5(4H)-thione, C3H6N4S, (I), has been redetermined with an improved model for the H atoms: the non-H atoms of (I) all lie on mirror planes in space group Pbcm, and the H atoms of the methyl group are disordered over two sets of reflection-related atomic sites having occupancy 0.5: two independent N—H...S hydrogen bonds link the molecules of compound (I) into complex sheets. The non-H atoms in the molecules of 4-[(E)-(3,4-dimethoxybenzylidene)amino]-3-methyl-1H-1,2,4-triazol-5(4H)-thione, C12H14N4O2S, (II), despite lying in general positions are close to planar, with a dihedral angle between the two rings of 6.31 (10)°: the molecules of compound (II) are linked by a three-centre N—H...(O)2 hydrogen bond into a C(10)C(11)[R12(5)] chain of rings. A second polymorph of 4-[(E)-(5-bromo-2-hydroxy-5-bromobenzylidene)amino]-3-methyl-1H-1,2,4-triazole-5(4H)-thione, C10H9BrN4OS, (III), has been identified; the non-H atoms are nearly co-planar with a dihedral angle between the two rings of 1.9 (4)°. There is an intramolecular O—H...N hydrogen bond and the molecules are linked by N—H...S hydrogen bonds, forming centrosymmetric R22(8) dimers. Comparisons are made with some related structures.

The structures of six chalcones containing 5-halogenothiophen-2-yl substituents are reported: (2E)-1-(5-chlorothiophen-2-yl)-3-(4-ethylphenyl)prop-2-en-1-one, C15H13ClOS, (I), and (2E)-1-(5-bromothiophen-2-yl)-3-(4-ethylphenyl)prop-2-en-1-one, C15H13BrOS, (II), are isostructural in space group P-1, while (2E)-1-(5-chlorothiophen-2-yl)-3-(4-ethoxyphenyl)prop-2-en-1-one, C15H13ClO2S, (III), and (2E)-1-(5-bromothiophen-2-yl)-3-(4-ethoxyphenyl)prop-2-en-1-one C15H13BrO2S, (IV), are isostructural in space group P21/c. There are no hydrogen bonds of any kind in the structures of compounds (I) and (II), but in the structures of compounds (III) and (IV), the molecules are linked into C(7) chains by means of C—H...O hydrogen bonds. In the structure of (2E)-3-(4-bromophenyl)-1-(5-chlorothiophen-2-yl)prop-2-en-1-one, C13H8BrClOS, (V), there are again no hydrogen bonds nor π–π stacking interactions but in that of (2E)-1-(5-bromothiophen-2-yl)-3-(3-methoxyphenyl)prop-2-en-1-one, C14H11BrO2S, (VI), the molecules are linked into C(5) chains by C—H...O hydrogen bonds. In each of compounds (I)–(VI), the molecular skeletons are close to planarity, and there are short halogen...halogen contacts in the structures of compounds (II) and (V) and a short Br...O contact in the structure of compound (VI). Comparisons are made with the structures of some similar compounds.

In the molecules of the title compounds, methyl 5-bromo-2-[(2-chloroquinolin-3-yl)methoxy]benzoate, C18H13BrClNO3, (I), methyl 5-bromo-2-[(2-chloro-6-methylquinolin-3-yl)methoxy]benzoate, C19H15BrClNO3, (II), methyl 2-[(2-chloro-6-methylquinolin-3-yl)methoxy]benzoate, C19H16ClNO3, (III), which crystallizes with Z′ = 4 in space group P212121, and 2-chloro-3-[(naphthalen-1-yloxy)methyl]quinoline, C20H14ClNO, (IV), the non-H atoms are nearly coplanar, but in {5-[(2-chloroquinolin-3-yl)methoxy]-4-(hydroxymethyl)-6-methylpyridin-3-yl}methanol, C18H17ClN2O3, (V), the planes of the quinoline unit and of the unfused pyridine ring are almost parallel, although not coplanar. The molecules of (I) are linked by two independent π–π stacking interactions to form chains, but there are no hydrogen bonds present in the structure. In (II), the molecules are weakly linked into chains by a single type of π–π stacking interaction. In (III), three of the four independent molecules are linked by π–π stacking interactions but the other molecule does not participate in such interactions. Weak C—H...O hydrogen bonds link the molecules into three types of chains, two of which contain just one type of independent molecule while the third type of chain contains two types of molecule. The molecules of (IV) are linked into chains by a C—H...π(arene) hydrogen bond, but π–π stacking interactions are absent. In (V), there is an intramolecular O—H...O hydrogen bond, and molecules are linked into sheets by a combination of O—H...N hydrogen bonds and π–π stacking interactions.

In the molecule of 3-chloro-2-(4-methylphenyl)-2H-pyrazolo[3,4-b]quinoline, C17H12ClN3, (I), the dihedral angle between the planes of the pyrazole ring and the methylated phenyl ring is 54.25 (9)°. The bond distances in the fused tricyclic system provide evidence for 10-π delocalization in the pyrazolopyridine portion of the molecule, with diene character in the fused carbocyclic ring. In the crystal, molecules of (I) are linked by two independent C—H...N hydrogen bonds, forming sheets containing centrosymmetric R22(16) and R64(28) rings, and these sheets are all linked together by π–π stacking interactions with a ring-centroid separation of 3.5891 (9) Å.

In 2,2′-bipyridin-1-ium 1,1,3,3-tetracyano-2-ethoxyprop-2-en-1-ide, C10H9N2+·C9H5N4O−, (I), the ethyl group in the anion is disordered over two sets of atomic sites with occupancies 0.634 (9) and 0.366 (9), and the dihedral angle between the ring planes in the cation is 2.11 (7)°. The two independent C(CN)2 groups in the anion make dihedral angles of 10.60 (6) and 12.44 (4)° with the central propenide unit, and the bond distances in the anion provide evidence for extensive electronic delocalization. In bis(2,2′-bipyridin-1-ium) 1,1,3,3-tetracyano-2-(dicyanomethylene)propane-1,3-diide [alternative name bis(2,2′-bipyridin-1-ium) tris(dicyanomethylene)methanediide], 2C10H9N2+·C10N62− (II), the dihedral angles between the ring planes in the two independent cations are 7.7 (2) and 10.92 (17)°. The anion exhibits approximate C3 symmetry, consistent with extensive electronic delocalization, and the three independent C(CN)2 groups make dihedral angles of 23.8 (2), 27.0 (3) and 27.4 (2)° with the central plane. The ions in (I) are linked by an N—H...N hydrogen bond and the resulting ion pairs are linked by two independent C—H...N hydrogen bonds, forming a ribbon containing alternating R44(18) and R44(26) rings, where both ring types are centrosymmetric. The ions in (II) are linked by two independent N—H...N hydrogen bonds and the resulting ion triplets are linked by a C—H...N hydrogen bond, forming a C21(7) chain containing anions and only one type of cation, with the other cation linked to the chain by a further C—H...N hydrogen bond.

The structures of three salts derived from clozapine, 8-chloro-11-(4-methylpiperazin-1-yl)-5H-dibenzo[b,e][1,4]diazepine, are reported, namely, clozapinium 3,5-dinitrobenzoate dimethyl sulfoxide monosolvate, C18H20ClN4+·C7H3N2O6−·C2H6OS, (I), where the dimethyl sulfoxide component is disordered over two sets of atomic sites having occupancies 0.627 (2) and 0.373 (2); clozapinium hydrogen maleate 0.21-hydrate, C18H20ClN4+·C4H3O4−·0.21H2O, (II), and clozapinium 2-hydroxybenzoate, C18H20ClN4+·C7H5O3−, (III). In all three salts, the protonation site is the methylated N atom of the piperazine ring, and the dimensions and conformations of the fused tricyclic system are very similar. However, differences are apparent in the piperazine component: in both compounds (II) and (III), the unprotonated N atom of this ring has a pyramidal geometry, but in compound (I) this atom has a planar geometry. In compound (III), both N-substituents in this ring occupy equatorial sites, but in compound (II) the fused tricyclic system occupies an axial site of the piperazine ring. The independent components of compound (I) are linked within the selected asymmetric unit by a combination of N—H...O and C—H...O hydrogen bonds, and these hydrogen-bonded aggregates are linked into chains by an aromatic π–π stacking interaction. In compound (II), the components are linked into sheets by a combination of O—H...O, N—H...O and C—H...O hydrogen bonds, and in compound (III), a combination of N—H...O, C—H...O and C—H...N hydrogen bonds links the components into a three-dimensional framework structure. Comparisons are made with some similar compounds.

In the cyclohexene ring of the title compound, C23H20BrNO3S, the –(CH2)4– atoms are positionally disordered [occupancy ratio = 0.753 (6):0.247 (6)]. The ring has a half-chair conformation for both the major and minor components. The dihedral angles between the mean plane of the thiophene ring and those of the benzene and phenyl rings are 35.2 (4) and 57.7 (3)°, respectively. The planes of the two aryl rings are twisted with respect to each other by 86.4 (6)°. In the molecule, there is an O—H...N hydrogen bond forming an S(6) ring motif. In the crystal, molecules are linked via C—H...O hydrogen bonds, forming chains parallel to [100].