Bis(2-amino-4-methyl­pyridinium) tetra­chloridocuprate(II)

The asymmetric unit of the title compound, (C6H9N2)2[CuCl4], consists of one cation and one half-anion, bis­ected by a twofold rotation axis through the metal center. The anion exhibits a geometry that is inter­mediate between a Td and D 4h arrangement about the Cu atom. The crystal structure contains chains of cations alternating with stacks of anions. The cationic groups inter­act via offset face-to-face π–π stacking, forming chains running along the c axis. The anion stacks are parallel to the cation chains, with no significant inter- nor intra­stack Cl⋯Cl inter­actions. There are several anion–cation hydrogen-bonding inter­actions of the (N—H)pyridine⋯Cl and (N—H)amino⋯Cl types, connecting the chains of cations to the stacks of anions. Both the N—H⋯Cl and π–π stacking inter­actions [centroid–centroid distances 3.61 (8) and 3.92 (2) Å] contribute to the formation of a three-dimensional supra­molecular architecture

2,5-Dibromo­pyridine

In the title compound, C5H3Br2N, C—H⋯N hydrogen-bonding inter­actions and Br⋯Br inter­actions [3.9418 (3) and 3.8986 (3) Å] connect the mol­ecules into planar sheets stacked perpendicular to the b axis. In addition, pyrid­yl–pyridyl inter­sheet π–π stacking inter­actions [centroid–centroid distance = 4.12 (1) Å] result in a three-dimensional network

Bis(2,6-dimethyl­pyridinium) tetra­bromido­zincate(II)

In the crystal structure of the title compound, (C7H10N)2[ZnBr4], the coordination geometry of the anion is approximately tetra­hedral and a twofold rotation axis passes through the Zn atom. The Zn—Br bond lengths range from 2.400 (2) to 2.408 (3) Å and the Br—Zn—Br angles range from 108.14 (6) to 115.15 (15)°. In the crystal structure, the [ZnBr4]2− anion is connected to two cations through N—H⋯Br and H2C—H⋯Br hydrogen bonds, forming two-dimensional cation–anion–cation layers normal to the b axis. No significant Br⋯Br inter­actions [the shortest being 4.423 (4) Å] are observed in the structure

3-Ammonio­pyridinium tetra­bromido­mercurate(II) monohydrate

The asymmetric unit of the title compound, (C5H8N2)[HgBr4]·H2O, consists of one cation, one anion and one water mol­ecule. The anion exhibits a distorted tetra­hedral arrangement about the Hg atom. The crystal structure contains alternating sheets of cations (in the ac plane) and stacks of anions. Several strong hydrogen-bonding inter­actions (pyN—H⋯Br and C—H⋯Br; py is pyridine), along with O—H⋯Br inter­actions, connect the sheets of cations to the stacks of anions. Cation–cation π–π stacking is also present (C⋯C distances in the range 3.424–3.865 Å). The shortest Br⋯Br distance is 3.9527 (9) Å

Bis(2,6-diamino-3,5-dibromo­pyridinium) hexa­bromidostannate(IV)

The asymmetric unit of the title compound, (C5H6Br2N3)2[SnBr6], contains one cation and one half-anion in which the Sn atom is located on a crystallographic centre of inversion and is in a quasi-octa­hedral geometry. The crystal structure is assembled via hydrogen-bonding inter­actions of two kinds, N(pyridine/amine)—H⋯Br—Sn, along with C—Br⋯Br—Sn interactions [3.4925 (19) Å]. The cations are involved in π–π stacking, which adds an extra supra­molecularity as it presents a strong case of offset-face-to-face motifs [centroid–centroid distance = 3.577 (3) Å]. The inter­molecular hydrogen bonds, short Br⋯Br inter­actions and π–π stacking result in the formation of a three-dimensional supra­molecular architecture

Bis(2-bromo­pyridinium) hexa­bromido­stannate(IV)

The asymmetric unit of the title compound, (C5H5BrN)2[SnBr6], contains one cation and one half-anion. The [SnBr6]2− anion is located on an inversion center and forms a quasi-regular octa­hedral arrangement. The crystal structure consists of two-dimensional supra­molecular layers assembled via hydrogen-bonding inter­actions of N—H⋯Br—Sn [D⋯A = 3.375 (13)–3.562 (13) Å and D—H⋯A = 127–142°, along with C—Br⋯Br synthons [3.667 (2) and 3.778 (3) Å]. These layers are parallel to the bc plane and built up from anions inter­acting extensively with the six surrounding cations

4-(4-Chloro­phen­yl)-1-(2-hydr­oxy-2,2-di­phenyl­acet­yl)thio­semicarbazide

The asymmetric unit of the title compound, C21H18ClN3O2S, contains two mol­ecules in which the bond lengths and angles are almost identical. Intra­molecular N—H⋯S hydrogen bonds result in the formation of two five-membered rings. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into centrosymmetric dimers; these dimers are linked via inter­molecular O—H⋯S hydrogen bonds, leading to infinite corrugated layers parallel to the bc plane through R 2 2(16) ring motifs

Bis(2,6-dimethyl­pyridinium) tetra­bromido­cobaltate(II)

In the crystal structure of the title compound, (C7H10N)2[CoBr4], the [CoBr4]2− anion is connected to two cations through N—H⋯Br and H2C—H⋯Br hydrogen bonds to form two-dimensional cation–anion–cation layers normal to the crystallographic b axis. Inter­actions of the π–π type are absent between cations in the stacks [centroid–centroid separation = 5.01 (5) Å]. Significant inter­molecular Br–aryl inter­actions are present in the structure, especially an unusually short Br–ring centroid inter­action of 3.78 (1) Å. The coordination geometry of the anion is approximately tetrahedral and a twofold rotation axis passes through the Co atom

Bis­(2-amino-6-methyl­pyridinium) tetra­bromido­cuprate(II)

In the crystal structure of the title compound, (C6H9N2)2[CuBr4], the geometry around the Cu atom is inter­mediate between tetra­hedral (Td) and square planar (D4h). Each [CuBr4]2− anion is connected non-symmetrically to four surrounding cations through N—H⋯X (pyridine and amine proton) hydrogen bonds, forming chains of the ladder-type running parallel to the crystallographic b axis. These layers are further connected by means of offset face-to-face inter­actions (parallel to the a axis), giving a three-dimensional network. Cation π–π stacking [centroid separations of 3.69 (9) and 3.71 (1) Å] and Br⋯aryl inter­actions [3.72 (2) and 4.04 (6) Å] are present in the crystal structure. There are no inter­molecular Br⋯Br inter­actions

Bis(2-bromo­pyridinium) hexa­chlorido­stannate(IV)

The asymmetric unit of the title compound, (C5H5BrN)2[SnCl6], contains one cation and one half-anion. The [SnCl6]2− anion is located on an inversion center and forms a quasi-regular octa­hedral arrangement. Hydrogen-bonding inter­actions of two kinds, viz. N—H⋯Cl—Sn and C—H⋯Cl—Sn, along with Cl⋯Br inter­actions [3.4393 (15) Å], connect the ions in the crystal structure into two-dimensional supra­molecular arrays. These supra­molecular arrays are arranged in layers approximately parallel to (110) built up from anions inter­acting with six symmetry-related surrounding cations