4,4′-Bi(1H-pyrazol-2-ium) tetra­chlorido­aurate(III) chloride: a three-dimensional cationic cooperite-like framework with multiple pyrazolium–chloride hydrogen-bonding inter­actions

In the title compound, (C₆H₈N₄)[AuCl₄]Cl, the 4,4′-bi(1H-pyrazol-2-ium) dication, denoted [H₂bpz]²⁺, is situated across a centre of inversion, the [AuCl₄]⁻ anion lies across a twofold axis passing through Cl—Au—Cl, and the Cl⁻ anion resides on a twofold axis. Conventional N—H...Cl hydrogen bonding [N...Cl = 3.109 (3) and 3.127 (3) Å, and N—H...Cl = 151 and 155°] between [H₂bpz]²⁺ cations (square-planar node) and chloride anions (tetra­hedral node), as complementary donors and acceptors of four hydrogen bonds, leads to a three-dimensional binodal four-connected framework with cooperite topology (three-letter notation pts). The framework contains channels along the c axis housing one-dimensional stacks of square-planar [AuCl₄]⁻ anions [Au—Cl = 2.2895 (10)–2.2903 (16) Å; inter­anion Au...Cl contact = 3.489 (2) Å], which are excluded from primary hydrogen bonding with the [H₂bpz]²⁺ tectons.

Cadmium(II) chloride, bromide and iodide complexes with 4,4′-bipyrid­azine: when are diazine and halide bridges (in)compatible?

In poly[di-μ-chlorido-μ-(4,4′-bipyridazine)-κ²N¹:N^1′-cad­mium(II)], [CdCl₂(C₈H₆N₄)]_n, (I), and its isomorphous bromide analogue, [CdBr₂(C₈H₆N₄)]_n, (II), the halide atom lies on a mirror plane and the Cd^II ion resides at the inter­section of two perpendicular mirror planes with m2m site symmetry. The pyridazine rings of the ligand lie in a mirror plane and are related to each other by a second mirror plane perpendicular to the first. The compounds adopt the characteristic structure of the [M^IIX₂(bipy)] type (bipy is bipyridine) based on crosslinking of [Cd(μ-X)₂]_n chains [Cd—Cl = 2.5955 (9) and 2.6688 (9) Å; Cd—Br = 2.7089 (4) and 2.8041 (3) Å] by bitopic rod-like organic ligands [Cd—N = 2.368 (3)–2.380 (3) Å]. This feature is discussed in terms of supra­molecular stabilization, implying that the periodicity of the inorganic chain [Cd...Cd = 3.7802 (4) Å in (I) and 3.9432 (3) Å in (II)] is favourable for extensive parallel π–π stacking of monodentate pyridazine rings, with centroid–centroid distances of 3.7751 (4) Å in (I) and 3.9359 (4) Å in (II). This is not the case for the longer iodide bridges, which cannot stabilize such a pattern. In poly[tetra-μ-iodido-μ₄-(4,4′-bipyridazine)-κ⁴N¹:N²:N^1′:N^2′-di­cadmium(II)], [Cd₂I₄(C₈H₆N₄)]_n, (III), the ligands are situated across a centre of inversion; they are tetra­dentate [Cd—N = 2.488 (2) and 2.516 (2) Å] and link successive [Cd(μ-I)₂]_n chains [Cd—I = 2.8816 (3)–3.0069 (4) Å] into corrugated layers.

A three-component cocrystal: benzoyl(hydroxy­imino)­acetonitrile-18-crown-6-water (2/1/4)

In the title compound, 2C₉H₆N₂O₂·C₁₂H₂₄O₆·4H₂O, the 18-crown-6 (1,4,7,10,13,16-hexa­oxa­cyclo­octa­decane) mol­ecule resides across a centre of inversion. The adduct exists as a mol­ecular hydrogen-bonded complex featuring integration of two kinds of synthons, viz. [(18-crown-6)(H₂O)₄] [O...O = 2.8645 (18)-2.9014 (18) Å] and an oxime/aqua ensemble, PhC(O)C(CN)NOH...OH₂ [O...O = 2.5930 (18) Å]. The reliability of the oxime/aqua motif, sustained by the highly acidic cyano­oxime, is an essential factor in the construction of multicomponent cocrystals and the accommodation of oxime species in macrocyclic hosts. The supra­molecular structure is generated by the alternation of hydro­philic [(18-crown-6)(H₂O)₄] layers and bilayers of benzoyl(hydroxy­imino)­aceto­nitrile mol­ecules, resulting in stacking inter­actions between the phenyl and cyano groups of 3.666 (2) Å.