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In the title complex salt, [Pd(C10H8N2)(C12H12N2O2)](CF3SO3)2, the palladium(II) atom is fourfold coordinated by two chelating ligands, 2,2′-bipyridine and 4,4′-dimethoxy-2,2′-bipyridine, in a distorted square-planar environment. In the crystal, weak π–π stacking interactions between the 2,2′-bipyridine rings [centroid-to-centroid distances = 3.8984 (19) Å] and between the 4,4′-dimethoxy-2,2′-bipyridine rings [centroid-to-centroid distances = 3.747 (18) Å] contribute to the alignment of the complex cations in columns parallel to the b-axis direction.

In the title complex, [Ru(C10H8N2)2(C6H6N2O)(H2O)](CF3SO3)2, the central RuII atom is sixfold coordinated by two bidentate 2,2′-bipyridine, an isonicotinamide ligand, and a water molecule in a distorted octahedral environment with trifluoromethanesulfonate ions completing the outer coordination sphere of the complex. Hydrogen bonding involving the water molecule and weak π–π stacking interactions between the pyridyl rings in adjacent molecules contribute to the alignment of the complexes in columns parallel to the c axis.

In the title complex, [Ni(C19H13N5)2](CF3SO3)2·(CH3CH2)2O, the central NiII atom is sixfold coordinated by three nitrogen atoms of each 2,6-bis(2-benzimidazolyl)pyridine ligand in a distorted octahedral geometry with two trifluoromethanesulfonate ions and a molecule of diethyl ether completing the outer coordination sphere of the complex. Hydrogen bonding contributes to the organization of the asymmetric units in columns along the a axis generating a porous supramolecular structure. The structure was refined as a two-component twin with a refined BASF value of 0.4104 (13).

In the title complex, [ZnCl2(C14H12N2O2)], the ZnII atom is located on a twofold rotation axis and is fourfold coordinated by two chlorido ligands and a bidentate 4,7-methoxy-1,10-phenanthroline ligand in a distorted tetrahedral environment. Weak π–π stacking interactions between adjacent 4,7-dimethoxy-1,10-phenanthroline rings [centroid-to-centroid distances = 3.5969 (11) and 3.7738 (11) Å] contribute to the alignment of the complexes in layers parallel to (\overline{2}01).

In the title complex, [ZnCl2(C12H12N2)]·CH3CN, the zinc(II) atom is fourfold coordinated by two chloride ligands and a bidentate 4,4′-dimethyl-2,2′-bipyridine ligand in a distorted tetrahedral shape with a molecule of acetonitrile sitting in the outer coordination sphere of the complex. π–π stacking interactions between the pyridyl rings in adjacent molecules contribute to the alignment of the complexes in columns parallel to the a axis.

In the title complex, [Pd(C10H8N2)(CH3CN)2](CF3SO3)2 or [Pd(bipy)(CH3CN)2](CF3SO3)2, the palladium(II) ion is fourfold coordinated by two acetonitrile molecules and a bidentate 2,2′-bipyridine ligand in a distorted square-planar geometry.

In the title complex, [Zn(C15H10ClN3)2](CF3SO3)2, the ZnII metal center is sixfold coordinated by three nitrogen atoms of each 4-chloroterpyridine ligand in a distorted octahedral geometry with triflouromethanesulfonate ions completing the outer coordination sphere of the complex. π–π stacking interactions between the pyridyl rings in adjacent molecules contribute to the alignment of the complexes in layers along the c axis.

The PdII central atom in the title complex, [PdCl(C26H24P2)(C6H6N2O)]NO3·CH3CN or [PdCl(dppe)(INAM)]NO3·CH3CN, where dppe is 1,2-bis(diphenylphosphanyl)ethane and INAM is isonicotinamide, exists in a slightly distorted square-planar environment defined by the two P atoms of the dppe ligand, a chloride ligand and the N atom of the isonicotinamide pyridyl ring. The crystal packing in the structure is held together by hydrogen bonds between the amide of the INAM ligand and the nitrate ions that complete the outer coordination sphere. A molecule of acetonitrile is also found in the asymmetric unit of the title complex.

The central AgI atom of the title salt, [Ag(INAM)2](CF3SO3)·2CH3CN, where INAM is isonicotinamide (C6H6N2O), is twofold coordinated by the pyridine N atoms of two isonicotinamide ligands creating a slightly distorted linear molecular geometry. The formation of polymeric chains {[Ag(INAM)2]+}n, held together by discrete hydrogen bonds through the amide group of the INAM ligand leaves voids for non-coordinating acetonitrile molecules that interact the silver metal center via regium bonds.

In the centrosymmetric title complex, [Cu2Cl2(C15H11N3)2](CF3O3S)2, the CuII metal center is fivefold coordinated by two chloride ions and three nitrogen atoms of the terpyridine ligand in a distorted square-pyramidal geometry; two trifluoromethanesulfonate ions complete the outer coordination sphere. π–π stacking interactions between the pyridyl rings in adjacent molecules contribute to the alignment of the complexes in columns along the a-axis. This structure represents the first example of a binuclear dication of formula [Cu(terpy)2Cl2]2+ with trifluoromethanesulfonate as counter-ions.

In the title complex, [Zn(C15H10ClN3)(NO3)2], the central zinc(II) atom is pentacoordinated by two O-bonded nitrate ions and three N atoms of the 4′-chloro-2,2′:6′,2′′-terpyridine ligand in a slightly distorted trigonal–bipyramidal shape. The main feature of the title complex packing is the presence of offset π–π interactions between the terpyridine rings in different layers. This structure constitutes the first known example of a zinc(II) 4-chloroterpyridine complex with coordinating nitrate ions.

The central copper(II) atom of the title salt, {[Cu(CF3SO3)(CH3CN)2(C12H12N2O2)](CF3SO3)}n or [[Cu(CH3CN)2(diOMe-bpy)(CF3SO3)](CF3SO3)]n where diOMe-bpy is 4,4′-dimethoxy-2,2′-bipyridine, C12H12N2O2, is sixfold coordinated by the N atoms of the chelating bipyridine ligand, the N atoms of two acetonitrile molecules, and two trifluoromethanesulfonate O atoms in a tetragonally distorted octahedral shape. The formation of polymeric chains [Cu(CH3CN)2(diOMe-bpy)(CF3SO3)]+n leaves voids for the non-coordinating trifluoromethanesulfonate anions that interact with the complex through weak hydrogen bonds. The presence of weakly coordinating ligands like acetonitrile and trifluoromethanesulfonate makes the title compound a convenient starting material for the synthesis of novel metal–organic frameworks.

In the title complex, [Zn(CF3O3S)Cl(C15H10ClN3)]·CH3CN, the zinc(II) core is fivefold coordinated by one chloride, one trifluoromethanesulfonate O atom and three terpyridine N atoms in a slightly distorted square-pyramidal geometry. The structure provides a distinct example amongst other zinc(II) 4-chloroterpyridine complexes because of the unusual planarity of the coordinated chloride, the short length of the Zn—N bond opposite to the chloride ligand [1.9572 (15) Å], and the presence of an elongated Zn—O bond [2.3911 (14) Å] in the coordinated trifluoromethanesulfonate ion. A molecule of acetonitrile is also found in the asymmetric unit of the title complex.

The title structures, [Zn2(C3H6NS2)4(C14H14N4O2)]·2C3H7NO (I) and [Zn2(C7H14NS2)4(C14H14N4O2)] (II), each feature a bidentate, bridging bipyridyl-type ligand encompassing a di-amide group. In (I), the binuclear compound is disposed about a centre of inversion, leading to an open conformation, while in (II), the complete molecule is completed by the application of a twofold axis of symmetry so that the bridging ligand has a U-shape. In each of (I) and (II), the dithiocarbamate ligands are chelating with varying degrees of symmetry, so the zinc atom is within an NS4 set approximating a square-pyramid for (I) and a trigonal-bipyramid for (II). The solvent dimethylformaide (DMF) molecules in (I) connect to the bridging ligand via amide-N—H...O(DMF) and various amide-, DMF-C—H...O(amide, DMF) interactions. The resultant three-molecule aggregates assemble into a three-dimensional architecture via C—H...π(pyridyl, chelate ring) interactions. In (II), undulating tapes sustained by amide-N—H...O(amide) hydrogen bonding lead to linear supramolecular chains with alternating molecules lying to either side of the tape; no further directional interactions are noted in the crystal.

The title compound, {[Cd(C9H11N2S2)2]·C6H7N}n, features two μ2-κ3-dithiocarbamate ligands each of which chelates one CdII atom, via the S atoms, while simultaneously bridging to another via the pyridyl-N atom. The result is a two-dimensional coordination polymer extending parallel to the ab plane with square channels along the b axis. The CdII atom geometry is based on a distorted cis-N2S4 octahedron. The 3-methylpyridine molecules reside in the channels aligned along the b axis, being held in place by methylene-C—H...N(3-methylpyridine) and (3-methylpyridine)-C—H...π(pyridyl) interactions. Pyridyl-C—H...S and dithiocarbamate-methyl-C—H...π(pyridyl) interactions provide connections between layers along the c axis.

The common feature of the molecular structures of the title compounds, [Zn(C5H10NS2)2(C5H5NO)], (I), and [Zn(C4H8NOS2)2(C5H5NO)], (II), are NS4 donor sets derived from N-bound hydroxypyridyl ligands and asymmetrically chelating dithiocarbamate ligands. The resulting coordination geometries are highly distorted, being intermediate between square pyramidal and trigonal bipyramidal for both independent molecules comprising the asymmetric unit of (I), and significantly closer towards square pyramidal in (II). The key feature of the molecular packing in (I) is the formation of centrosymmetric, dimeric aggregates sustained by pairs of hydroxy-O—H...S(dithiocarbamate) hydrogen bonds. The aggregates are connected into a three-dimensional architecture by methylene-C—H...O(hydroxy) and methyl-C—H...π(chelate) interactions. With greater hydrogen-bonding potential, supramolecular chains along the c axis are formed in the crystal of (II), sustained by hydroxy-O—H...O(hydroxy) hydrogen bonds, with ethylhydroxy and pyridylhydroxy groups as the donors, along with ethylhydroxy-O—H...S(dithiocarbamate) hydrogen bonds. Chains are connected into layers in the ac plane by methylene-C—H...π(chelate) interactions and these stack along the b axis, with no directional interactions between them. An analysis of the Hirshfeld surfaces clearly distinguished the independent molecules of (I) and reveals the importance of the C—H...π(chelate) interactions in the packing of both (I) and (II).

The asymmetric unit in the title binuclear compound, [Cd(C6H12NOS2)2(C12H10N4)]2·2H2O, comprises a CdII atom, two dithiocarbamate (dtc) anions, a monodentate 3-pyridinealdazine ligand and a lattice water molecule. The binuclear molecule is constructed by the application of inversion symmetry. One dtc ligand simultaneously chelates one cadmium atom and bridges the centrosymmetric mate, while the other dtc ligand is chelating only. This leads to a centrosymmetric [Cd(dtc)2]2 core to which are appended two 3-pyridinealdazine ligands. The resulting NS5 donor set is based on an octahedron. The three-dimensional molecular packing is sustained by hydroxyl-O—H(hydroxyl) and water-O—H...O(hydroxyl) hydrogen bonding, leading to supramolecular layers parallel to (101) which are connected by water-O—H...N(pyridyl) hydrogen bonding; additional C—H...O, S π(chelate ring) interactions are also evident. The retention of the central [Cd(dtc)2]2 core upon adduct formation is unprecedented in the structural chemistry of the zinc-triad dithiocarbamates.

The asymmetric unit of the title compound, [Cd2(C12H10N2)3(C6H12NOS2)4]·4C2H3N, comprises a CdII atom, two dithiocarbamate (dtc) anions, one and a half trans-1,2-dipyridin-4-ylethylene (bpe) molecules and two acetonitrile solvent molecules. The full binuclear complex is generated by the application of a centre of inversion. The dtc ligands are chelating, one bpe molecule coordinates in a monodentate mode while the other is bidentate bridging. The resulting cis-N2S4 coordination geometry is based on an octahedron. Supramolecular layers, sustained by hydroxy-O—H...O(hydroxy) and hydroxy-O—H...N(bpe) hydrogen bonding, interpenetrate to form a three-dimensional architecture; voids in this arrangement are occupied by the acetonitrile solvent molecules. Additional intermolecular interactions falling within the specified framework have been analysed by Hirshfeld surface analysis, including π–π interactions.

The sulfathiazole molecule in the title 1:1 co-crystal, C9H9N3O2S2·C18H12N6, adopts an approximate L-shape [dihedral angle between the five- and six-membered rings = 86.20 (9)°] and features an intramolecular hypervalent S...O interaction [2.8666 (15) Å]. Overall, the triazine molecule has the shape of a disk as the pendant pyridine rings are relatively close to coplanar with the central ring [dihedral angles = 18.35 (9), 6.12 (9) and 4.67 (9)°]. In the crystal packing, a linear supramolecular chain aligned along [01-1] is formed as a result of amino–pyridyl N—H...N hydrogen bonding with syn-disposed pyridyl molecules of one triazine, and amine–pyridyl N—H...N hydrogen bonding with the third pydridyl ring of a second triazine molecule. A three-dimensional architecture arises as the chains are connected by C—H...O interactions.

The asymmetric unit of the title co-crystal, C12H12N2·2C7H7NO2, comprises a centrosymmetric 4-[2-(pyridin-4-yl)ethyl]pyridine molecule and a 2-aminobenzoic acid molecule in a general position. The acid has a small twist between the carboxylic acid residue and the ring [dihedral angle = 7.13 (6)°] despite the presence of an intramolecular N—H...O(carbonyl) hydrogen bond. Three-molecule aggregates are formed via O—H...N(pyridyl) hydrogen bonds, and these are connected into supramolecular layers in the bc plane by N—H...O(carbonyl) hydrogen bonds and π–π interactions between pyridine and benzene rings [inter-centroid distance = 3.6332 (9) Å]. Layers are connected along the a axis by weak π–π interactions between benzene rings [3.9577 (10) Å].

The asymmetric unit of the title salt, C12H14N22+·2C7H3N2O6−, comprises half a 4-[2-(pyridin-1-ium-4-yl)ethyl]pyridin-1-ium dication, being disposed about a centre of inversion, and a 2,6-dinitrobenzoate anion, in a general position. In the anion, the carboxylate group is inclined to the benzene ring [dihedral angle = 85.45 (9)°], whereas near-coplanar and twisted arrangements are found for the nitro groups [O—N—C—C torsion angles = 179.80 (14) and 20.2 (2)°]. In the crystal, three-component aggregates sustained by charge-assisted N+—H...O− hydrogen bonds are found and these are consolidated into a three-dimensional architecture by C—H...O and π–π [inter-centroid distances = 3.6796 (14) and 3.7064 (14) Å] interactions.

The asymmetric unit of the title co-crystal, C12H14N4O2S·0.5C6H12N2, comprises the sulfonamide molecule and half a molecule of 1,4-diazabicyclo[2.2.2]octane (DABCO), the latter being disposed about a crystallographic twofold rotation axis. In the sulfonamide molecule, the aromatic rings are almost perpendicular to one another [dihedral angle = 75.01 (8)°]. In the crystal, molecules are connected into a three-molecule aggregate via amide–DABCO N—H...N hydrogen bonds, and these are connected into a three-dimensional architecture via amino–DABCO N—H...O and amino-pyrimidine N—H...N hydrogen bonds.

The asymmetric unit of title co-crystal, C14H16N4S22+·2C7H3N2O6−·4C7H4N2O6, comprises a centrosymmetric dipyridinium dication, a 2,6-dinitrobenzoate anion and two independent 2,6-dinitrobenzoic acid molecules. The pyridinium rings are each approximately perpendicular to the central dithioamide unit [dihedral angle = 80.67 (12)°]. The carboxylate/carboxylic acid groups are approximately perpendicular to the benzene ring to which they are attached [dihedral angles = 78.85 (16), 81.46 (19) and 71.28 (15)°]. By contrast, the major twist exhibited by a nitro group is manifested in a dihedral angle of 32.66 (17)°. The most prominent feature of the crystal packing is linear supramolecular chains along [1-10], featuring O—H...O(carboxylate) and pyridinium-N—H...O hydrogen bonds. These are consolidated into a three-dimensional architecture by thioamide–nitro N—H...O, C—H...O and π–π [inter-centroid distance = 3.524 (2) Å] interactions. One of the nitro O atoms was refined over two sites; the major site was 0.65 (7) occupied.

The asymmetric unit of title salt co-crystal, [K(C9H11N2S2)(C12H24O6)], comprises a K+ cation, an −S2CN(Et)py anion and a 18-crown-6 molecule. Substantial delocalization of π-electron density is evident in the dithiocarbamate anion, as indicated by the equivalent C—S bond lengths. The K+ cation sits within an O6S2 donor set lying 0.7506 (6) Å out of the least-squares plane through the six O atoms (r.m.s. deviation = 0.1766 Å) of the 18-crown-6 molecule with the two S atoms being on one side of this plane. Supramolecular layers in the bc plane, sustained by C—H...O and C—H...π interactions, feature in the crystal packing.

The asymmetric unit of title co-crystal, C10H8N2·2C7H7NO2, comprises a centrosymmetric 4,4′-bipyridine molecule, and a 2-aminobenzoic acid molecule in a general position. The latter is effectively planar [C—C—C—O torsion angle = 5.0 (3)°] owing to an intramolecular N—H...O(carbonyl) hydrogen bond. Three-molecule aggregates are formed via O—H...N(pyridyl) hydrogen bonds and these are connected into supramolecular layers in the bc plane by N—H...O(carbonyl) hydrogen bonds and π–π interactions between pyridyl and benzene rings [inter-centroid distance = 3.634 (2) Å]. Layers are connected along the a axis by weak π–π interactions between benzene rings [3.964 (2) Å].

The asymmetric unit of the title co-crystal, 2C14H13N2+·C10H4O82−·2C14H12N2·C10H6O8, comprises a 2,9-dimethyl-1,10-phenanthrolin-1-ium cation (Me2PhenH+) and a 2,9-dimethyl-1,10-phenanthroline molecule (Me2Phen), each in a general position, and half each of a 2,5-dicarboxybenzene-1,4-dicarboxylate dianion (LH22−) and a benzene-1,2,4,5-tetracarboxylic acid molecule (LH4), each being disposed about a centre of inversion. Small twists are evident in the dianion [the C—C—C—O torsion angles are 168.41 (18) and 16.2 (3)°], whereas a major twist is found for one carboxylic acid group in the neutral molecule [C—C—C—O = 66.3 (2) and 18.2 (3)°]. The most prominent feature of the crystal packing is the formation of linear supramolecular chains along [001] mediated by charge-assisted O—H...O− hydrogen bonding between alternating LH4 and LH22−. These are connected to the Me2PhenH+ and Me2Phen species by N—H...O and O—H...N hydrogen bonds, respectively. A three-dimensional architecture is formed by C—H...O and π–π interactions [inter-centroid distance = 3.5337 (17) Å].

The asymmetric unit of the title co-crystal, C10H6O8·2C8H10N4O2, comprises a centrosymmetric benzene-1,2,4,5-tetracarboxylic acid (LH4) molecule and a molecule of caffeine in a general position. LH4 is nonplanar, with the dihedral angles between the ring and pendent carboxylic acid groups being 44.22 (7) and 49.74 (7)°. By contrast, the caffeine molecule is planar (r.m.s. deviation = 0.040 Å). Supramolecular layers parallel to (-1-10) are sustained by carboxylic acid O—H...O(carbonyl) and O—H...N(imidazole) hydrogen bonds, as well as by methyl–carbonyl C—H...O interactions. These stack via π–π interactions between the benzene and imidazole rings [inter-centroid distance = 3.4503 (10) Å].

The title hydrated salt, C6H6NO2+·C10H5O8−·H2O, was isolated from the 1:1 cocrystallization of benzene-1,2,4,5-tetracarboxylic acid and isonicotinic acid in ethanol solution. In the crystal, the cation is close to planar [r.m.s. deviation = 0.085 Å for the nine fitted atoms; the C—C—C—O(carbonyl) torsion angle = −8.7 (4)°], but twists are evident in the anion, with all but the carboxylic acid group diagonally opposite the carboxylate group being significantly twisted out of the plane of the benzene ring [C—C—C—O(carbonyl) torsion angles = −118.1 (2), −157.6 (2), 4.3 (3) and 77.3 (3)°]. In the crystal, the ions and water molecules are consolidated into a three-dimensional architecture by O—H...O and N—H...O hydrogen bonding along with C—H...O interactions.

Two pairs of independent cations and anions comprise the asymmetric unit of the title salt, C6H16NO+·C9H8N3O2S2−. The cations are virtually superimposable and each exhibits a gauche disposition of the hydroxy O and ammonium N atoms [the O—C—C—N torsion angles are 55.5 (3) and 57.5 (3)°]. Significant differences are seen in the molecular structures of the anions as seen in the S—N—C—S [1.1 (3) and 32.9 (3)°] and C—S—N—C [−69.7 (2) and 91.4 (2)°] torsion angles. Despite the variations in conformation, intramolecular hypervalent S...O interactions persist in each anion [3.078 (2) and 2.8730 (19) Å]. In the crystal, supramolecular double layers are formed in the bc plane, being sustained by O—H...N, N—H...O and N—H...N hydrogen bonding. These are connected along the a axis via C—H...O interactions.

The asymmetric unit of the title compound, [Zn(C4H8NOS2)2(C18H12N6)]·1.5C4H8O2, comprises a Zn-containing molecule and one and a half dioxane molecules as one of the solvent molecules is located about a crystallographic inversion centre. The approximately square-pyramidal N3S2 donor set is defined by two monodentate dithiocarbamate ligands and two pyridine and one triazine N atom from the tridentate triazine ligand. Molecules are connected into a supramolecular array via O—H...S and O—H...N hydrogen bonds. These stack along the b axis and the solvent molecules reside in the channels thus formed.

The title 1:1 co-crystal, C7H7NO2·C10H8N2S2, features a highly twisted 4-(pyridin-4-yldisulfanyl)pyridine molecule [dihedral angle between the pyridine rings = 89.06 (10)°]. A small twist is evident in the 2-aminobenzoic acid molecule, with the C—C—C—O torsion angle being −7.7 (3)°. An N—H...O hydrogen bond occurs in the 2-aminobenzoic acid molecule. In the crystal, molecules are linked by O—H...N and N—H...N hydrogen bonds into a supramolecular chain along the b axis. These are connected into layers by π–π interactions occurring between pyridine rings [centroid–centroid distance = 3.8489 (15) Å]. The layers are connected along the a axis by C—H...O contacts. The crystal studied was a racemic twin.

A 4-aza-1-azoniabicyclo[2.2.2]octane cation, a 2-aminobenzoate anion and a neutral 2-aminobenzoic acid molecule comprise the asymmetric unit of the title compound, C6H13N2+·C7H6NO2−·C7H7NO2. An intramolecular N—H...O hydrogen bond occurs in the anion and in the neutral 2-aminobenzoic acid molecule. The cation provides a charge-assisted N—H...O hydrogen bond to the anion, and the 2-aminobenzoic acid molecule forms an O—H...N hydrogen bond to the unprotonated amino N atom in the cation. In this way, a three-component aggregate is formed. These are connected into a three-dimensional network by amino–carboxylate N—H...O hydrogen bonds. N—H...N hydrogen bonds are also observed.

The asymmetric unit of the title cocrystal, C12H10N4·2C7H6O2, comprises a single molecule of benzoic acid and one half-molecule of 2-pyridinealdazine situated about a centre of inversion. The carboxyl group is coplanar with the benzene ring to which it is connected [O—C—C—C = −172.47 (12)°] and similarly, the 2-pyridinealdazine molecule is planar (r.m.s. deviation of the 16 non-H atoms = 0.017 Å). In the crystal, molecules are connected into a non-planar three-molecule aggregate [dihedral angle between the benzene and pyridyl ring connected by the hydrogen bond = 61.30 (7)°] with a twisted Z-shape. Layers of 2-pyridinealdazine molecules in the ab plane are sandwiched by benzoic acid molecules being connected by O—H...N and C—H...O interactions, the latter involving the carbonyl O atom so that each benzoic acid molecule links three different 2-pyridinealdazine molecules. Interdigitated layers stack along the c axis.

In the title co-crystal, C12H10N4·2C7H6O2, the complete 4-pyridinealdazine molecule is generated by a crystallographic centre of inversion. In the crystal, molecules are connected into a three component aggregate via O—H...N hydrogen bonds. As both the benzoic acid [O—C—C—C torsion angle = 174.8 (2)°] and 4-pyridinealdazine (r.m.s. deviation of the 16 non-H atoms = 0.041 Å) molecules are almost planar, the resulting three-component aggregate is essentially planar. The crystal packing comprises layers of the three-component aggregates of alternating orientation stacked along the b axis; the connections between the molecules are of the types C—H...π and π–π [pyridine–benzene centroid–centroid distance = 3.787 (4) Å].

The components of the title 1:1 co-crystal, C14H10N4·C6F4I2, are connected via an N...I [2.959 (4) Å] halogen bond, in which the N atom is part of the relatively electron-rich pyrazine ring. The C6F4I2 molecule is almost planar [r.m.s. deviation = 0.038 Å] but there are significant twists in the pyrazine derivative, as seen in the dihedral angles [31.3 (2) and 54.6 (2)°] formed between the pendant pyridyl rings and the central pyrazine ring. The bimolecular aggregates are sustained in the crystal by C—H...F and π–π interactions [ring centroid(pyridyl)–ring centroid(benzene) = 3.678 (3) Å].

The asymmetric unit of the polymeric title salt, {[Ag(C5H5NO)2]PF6}n, comprises an AgI cation (located on a twofold axis), two 2-pyridone ligands (with distinct coordination modes), and half a PF6− anion (situated on a centre of inversion). The AgI atom is in an approximately octahedral AgO6 coordination geometry, which is stabilized by intramolecular N—H...O hydrogen bonds. The result of the bridging mode of the 2-pyridone ligand is the formation of a supramolecular chain along the c axis; these are consolidated in the crystal by C—H...F interactions.

The asymmetric unit of the title co-crystal, C12H10N4·2C8H8O2, comprises a single molecule of 2-phenylacetic acid and half a molecule of 4-pyridinealdazine as this is situated about a centre of inversion. Molecules are connected into a three component aggregate via O—H...N hydrogen bonds. As the carboxylic acid group is almost normal to the plane through the benzene ring to which it is attached [C—C—C—C = 93.7 (3) °], and the 4-pyridinealdazine molecule is planar (r.m.s. deviation of the 16 non-H atoms = 0.010 Å), the overall shape of the aggregate is that of an extended chair. In the crystal packing, layers of three component aggregates stack along the c axis.

The asymmetric unit of the title 1:1 adduct, C10H8N2S·C6F4I2, comprises a half-molecule of 1,2,4,5-tetrafluoro-3,6-diiodobenzene, and half a 4-(pyridin-4-ylsulfanyl)pyridine molecule. The former is completed by crystallographic inversion symmetry, the latter by twofold symmetry, with the S atom lying on the rotation axis. The almost planar 1,2,4,5-tetrafluoro-3,6-diiodobenzene molecule (r.m.s. deviation of all 12 atoms = 0.016 Å) and twisted 4-(pyridin-4-ylsulfanyl)pyridine molecule [dihedral angle between pyridyl rings = 54.88 (13)°] are connected by N...I interactions [2.838 (4) Å], generating a supramolecular chain with a step-ladder topology. These chains are connected in the crystal by C—H...F and C—H...π(pyridyl) interactions.

In the title salt, [Ag2(CF3CO2)2(C10H8N2)]n, which may also be regarded as a coordination polymer if long Ag...O interactions are considered, each of the N atoms of the somewhat twisted 2,2′-bipyridine molecule [N—C—C—N = −27.5 (4)°] binds to an Ag atom, and each of the carboxylate ligands is tridentate, linking to three Ag atoms. The bidentate carboxylate O atoms bridge the same two Ag atoms, resulting in the formation of Ag2O2 rings. These rings are bridged by the 2,2′-bipyridine ligands, forming a chain along the b axis. The chains are linked into double chains via the remaining Ag—O bonds and Ag...Ag contacts. As a consequence of the Ag...Ag contacts, the NO4 donor set about each Ag atom is heavily distorted. Finally, the chains are linked into a three-dimensional network by a combination of C—H...O and C—H...F interactions.

The asymmetric unit of the title cocrystal, C14H14N4O2·C14H10O4S2, comprises a twisted 2,2′-(disulfanediyl)dibenzoic acid molecule [dihedral angle between the benzene rings = 76.35 (10)°] and a U-shaped N,N′-bis(3-pyridylmethyl)ethanediamide molecule with the pyridyl groups lying to the same side of the central diamide moiety [C—C—C—N = 113.8 (2) and −117.6 (2)°]. The latter aggregate into supramolecular tapes propagating along the a axis via centrosymmetric eight-membered amide {...OCNH}2 synthons. Intramolecular N—H...O hydrogen bonds are observed. The 2,2′-(disulfanediyl)dibenzoic acid molecules form carboxyl–pyridine O—H...N hydrogen bonds, bridging a pyridine residue below the plane of the tape and one above the plane with two intervening N,N′-bis(3-pyridylmethyl)ethanediamide molecules. The supramolecular chains are consolidated in the crystal packing by C—H...O contacts. An intermolecular C—H...S interaction also occurs.

The asymmetric unit of the title 1:2 adduct, C12H10N4·2C8H8O2, comprises a single molecule of 2-phenylacetic acid and half a molecule of 3-pyridinealdazine; the latter is completed by crystallographic inversion symmetry. In the crystal, molecules are connected into a three-component aggregate via O—H...N hydrogen bonds. As the carboxyl group lies above the plane through the benzene ring to which it is attached [C—C—C—C = 62.24 (17)°] and the 4-pyridinealdazine molecule is almost planar (r.m.s. deviation of the 16 non-H atoms = 0.027 Å), the overall shape of the aggregate is that of a flattened extended chair. Layers of these aggregates are connected by C—H...O and C—H...π interactions and stack parallel to (220).

In the title compound, [Ag(CF3SO3)(C8H10N4O2)2(H2O)], the AgI atom is coordinated by two caffeine N atoms and, at longer distances, two O atoms of a coordinated water molecule and the trifluoromethanesulfonate anion, resulting in an AgN2O2 seesaw geometry. The caffeine molecules are roughly coplanar [dihedral angle = 5.81 (5)°]. In the crystal, molecules self-assemble into a linear supramolecular chain along the c axis via O—H...O hydrogen bonds involving the coordinated water moledcule and carbonyl O atoms. The packing is consolidated by weak C—H...O interactions.

The asymmetric unit of the title co-crystal solvate, C14H10O4S2·2C14H12N2·C4H8O, comprises a 2,2′-(disulfanediyl)dibenzoic acid molecule, two molecules of 2,9-dimethylphenanthroline and a tetrahydrofuran (THF) solvent molecule. Each end of the twisted diacid [dihedral angle between the benzene rings = 74.33 (17)°] forms a strong O—H...N hydrogen bond with a 2,9-dimethylphenanthroline molecule, forming a trimeric aggregate. The crystal structure comprises layers of acid and THF molecules, and layers of 2,9-dimethylphenanthroline molecules that alternate along the a axis, the main connections between them being of the type C—H...O.

In the crystal of the title 1:1 adduct, C8H7ClO2·C12H10N4, the components are linked by an O—H...N hydrogen bond between the carboxylic acid and one of the pyridine N atoms. In the acid, the carboxylic acid group is approximately normal to [dihedral angle = 72.9 (2)°] but twisted with respect to the plane through the benzene ring [C—C—C—O torsion angle = 25.4 (5)°]. The base is roughly planar [dihedral angle between rings = 12.66 (15)°; r.m.s. deviation of the 16 non-H atoms = 0.107 Å] and the conformations about both imine bonds are E. The dimeric aggregates are linked into a supramolecular layer in the ab plane by C—H...O interactions.

The constituents of the title co-crystal, C12H14N4O2S·C7H6O2, are connected by an eight-membered hetero-synthon {...NCNH...OCOH}, whereby the carboxylic acid forms donor and acceptor hydrogen bonds with a pyrimidine N atom and the adjacent amine, respectively. The dimeric aggregates thus formed are arranged in rows with their terminal NH2 groups forming N—H...O hydrogen bonds with neighbouring aggregates to form a two-dimensional array in the ac plane with an overall T-shaped topology. Layers interdigitate along the b axis being connected by C—H...O, C—H...π and π–π [centroid–centroid distance = 3.6316 (19) Å] interactions.

The asymmetric unit of the title salt, [Ag(C14H14N4O2)1.5](CF3SO3), comprises a Ag+ cation, three half-molecules of N,N′-bis(2-pyridylmethyl)oxalamide (each of which is disposed about a centre of inversion) and a trifluoromethanesulfonate anion. Distinct coordination modes are found for the bridging ligands, i.e., a μ2,κ2-bridging mode involving pyridine N atoms for one ligand, and a μ2,κ4-bridging mode, employing both pyridine N and amide O atoms for the remaining ligands. The Ag+ cations, which are in a distorted square-pyramidal coordination, and the ligands combine to form a two-dimensional array parallel to (101); these arrays are connected into a three-dimensional structure by trifluoromethanesulfonate anions via N—H...O, C—H...O, and C—F...O interactions.

There are two independent but virtually identical molecules of each component in the asymmetric unit of the title 1:1 adduct, C6H12N2·C6H6O2. In the crystal, the constituents are connected into a supramolecular chain along the b axis by O—H...N hydrogen bonds. Weak C—H...O bonds cross-link the chains.

The constituents of the title 1:1 co-crystal, C7H6O2·C14H12N2, are connected into dimeric aggregates by a bifurcated O—H...N hydrogen bond; the hydroxyl-H atom is hydrogen bonded to the two N atoms of the 2,9-dimethylphenanthroline. The hydrogen-bonded residues are almost orthogonal to each other [dihedral angle = 78.56 (7) °]. In the crystal packing, the aggregates are assembled into layers in the bc plane by π...π interactions [ring centroid...ring centroid distance = 3.5577 (16) Å] involving the pyridyl rings, and C–H...π contacts involving the phenanthroline-H atom and the phenyl ring of the acid.

The title compound, [PdCl2(C6H16N3)](C7H7SO3), consists of a PdII atom bonded to two N atoms of the 1,4,7-triazacyclononane (TACN) ligand and two chloride ions, which define a distorted square-planar geometry. The third N atom of the TACN ligand is protonated and hydrogen bonds to the p-toluenesulfonate anion. The Cl—Pd—Cl angle is larger than the N—Pd—N angle. The packing is dominated by layers, which are formed by the criss-crossing of two different hydrogen-bonded chains. One chain is composed of hydrogen-bonded Pd(TACNH)Cl2+ cations, while the second is formed through hydrogen bonding between the p-toluenesulfonate anion and the Pd(TACNH)Cl2+ cation.

In the methanol solvate of the title 1:1 cocrystal, C29H28F6N4OS·C5H9NO2·CH4O, the l-proline molecule exists as a zwitterion. In the crystal, the disubstituted thiourea, l-proline and methanol molecules are linked by N—H...O and N—H...N hydrogen bonds, forming a two-dimensional array in the ab plane.