Solid state coordination chemistry of the copper(I)–cyano–organodiimine system. Two- and three-dimensional copper cyanide phases incorporating linear dipodal ligands

Abstract

A series of composite inorganic–organic materials from the copper/cyanide/organoimine system have been isolated and structurally characterized. The structural consequences of introducing sterically demanding substituents and of expanding the donor to donor distance in linear dipodal organodiimine ligands has been addressed, exploiting the bridging bidentate ligands pyrazine (pyr), 2-methylpyrazine (mpyr), 2-ethylpyrazine (etpyr), 2,3-dimethylpyrazine (2,3-dmp), 2,5-dimethylpyrazine (2,5-dmp), 2,6-dimethylpyrazine (2,6-dmp), quinoxaline (qox), phenazine (phenz), 4,4′-bipyridine (4,4′-bpy) and trans-4,4′-bipyridylethylene (dpe). Hydrothermal reactions of CuCN and KCN with the appropriate ligand yielded two general subclasses of materials: two-dimensional networks and three-dimensional frameworks. The 2-D phases include [Cu₃(CN)₃(pyr)] (1), [Cu₂(CN)₂(etpyr)] (2), [Cu₂(CN)₂(tmp)] (3), [Cu₂(CN)₂(qox)] (4), [Cu₂(CN)₂(phenz)] (5) and [Cu₇(CN)₇(4,4′-bpy)₂] (6). The 3-D materials are represented by [Cu₃(CN)₃(pyr)₂] (7), [Cu₂(CN)₂(mpyr)] (8), [Cu₂(CN)₂(2,3-dmp)] (9), [Cu₂(CN)₂(2,5-dmp)] (10), [Cu₂(CN)₂(2,6-dmp)] (11), [Cu₂(CN)₂(4,4′-bpy)](12) and [Cu₂(CN)₂(dpe)] (13). The materials characteristically exhibit {Cu(CN)}_n chains and/or {Cu_x(CN)_x} rings as structural motifs. The detailed connectivity between such substructures is influenced by the identity of the organodiimine ligand and the associated steric demands and spatial extension. The syntheses and structural characterization by X-ray diffraction of 1–13 are discussed in relation to the supramolecular chemistry of other copper cyanide solid state materials.