Bis[(1RS,2RS)-4,4′-(1-aza­niumyl-2-hy­droxy­ethane-1,2-di­yl)dipyridinium] tris­[tetra­chloridopalladate(II)]

The asymmetric unit of the title compound, (C₁₂H₁₆N₃O)₂[PdCl₄]₃, consists of a 4,4′-(1-aza­niumyl-2-hy­droxy­ethane-1,2-di­yl)dipyridinium dication and one and a half tetra­chloridopalladate(II) anions; the latter has inversion symmetry. In the cation, the pyridinium rings attached to the central 1-aza­niumyl-2-hy­droxy­ethane fragment show an anti conformation, as indicated by the central C—C—C—C torsion angle of −178.1 (4)°, and they are inclined to one another by 25.7 (2)°. In the crystal, the cations and anions are linked through N—H...Cl and O—H...Cl hydrogen bonds. There are also π–π contacts [centroid–centroid distance = 3.788 (3) Å] and a number of C—H...O and C—H...Cl inter­actions are present, consolidating the formation of a three-dimensional structure.

(1RS,2RS)-4,4′-(1-Aza­niumyl-2-hy­droxy­ethane-1,2-di­yl)dipyridinium tetra­chlorido­platinate(II) chloride

The title compound, (C₁₂H₁₆N₃O)[PtCl₄]Cl, consists of a 4,4′-(1-aza­niumyl-2-hy­droxy­ethane-1,2-di­yl)dipyridinium trication, a square-planar tetra­chloridoplatinate(II) dianion and a chloride ion. In the cation, the pyridinium rings attached to the central 1-aza­niumyl-2-hy­droxy­ethane fragment have an anti conformation, as indicated by the central C—C—C—C torsion angle of −166.5 (6)°, and they are inclined to one another by 63.5 (4)°. In the crystal, the cations and anions are linked through N—H...Cl and O—H...Cl hydrogen bonds. There are also π–π contacts [centroid–centroid distances = 3.671 (4) and 3.851 (4) Å] and a number of C—H...Cl inter­actions present, consolidating the formation of a three-dimensional supra­molecular structure.

Bis{2-[2,5-bis­(pyridin-2-yl)-1H-imidazol-4-yl]pyridinium} tetra­cyanidoplatinate(II) tetra­hydrate

The asymmetric unit of the title hydrated complex salt, (C₁₈H₁₄N₅)₂[Pt(CN)₄]·4H₂O, consists of one 2-[2,5-bis­(pyridin-2-yl)-1H-imidazol-4-yl]pyridinium cation, half a tetra­cyanidoplatinate(II) dianion, which is located about a crystallographic inversion center, and two water mol­ecules of crystallization. The Pt^II atom has a square-planar coordination environment, with Pt—C_CN distances of 1.992 (4) and 2.000 (4) Å. In the cation, there is an N—H...N hydrogen bond linking adjacent pyridinium and pyridine rings in positions 4 and 5. Despite this, the organic component is non-planar, as shown by the dihedral angles of 10.3 (2), 6.60 (19) and 15.66 (18)° between the planes of the central imidazole ring and the pyridine/pyridinium substituents in the 2-, 4- and 5-positions. In the crystal, cations and anions are linked via O—H...O, O—H...N and N—H...O hydrogen bonds, forming a three-dimensional network. Additional π–π, C—H...O and C—H...N contacts provide stabilization to the crystal lattice.

Cyclo­hexane-1,4-dicarb­oxy­lic acid–pyridinium-4-olate (1/1)

In the title adduct, C₅H₅NO·C₈H₁₂O₄, the heterocycle exists in its zwitterionic form. The cyclo­hexane ring exhibits a chair conformation with the carb­oxy­lic acid groups in equatorial and axial orientations. In the crystal, mol­ecules are linked through charge-assisted O—H...O⁻, N⁺—H...O⁻ and N⁺—H...O hydrogen bonds, and an additional series of C—H...O contacts, giving a pleated two-dimensional hydrogen-bonded network parallel to (-204).