Solvent and counter ion effects in bis(imidazole) dinuclear heterometallacyclic complexes of gold(I): Some considerations of porosity

Abstract

Cyclic 2:2 complexes of Au I and bitmb [1,3-bis(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene] were prepared and the structures of [Au 2(μ-bitmb) 2](BF 4) 2·2CH 3CN ( 1·2CH 3CN), [Au 2(μ-bitmb) 2](BF 4) 2·2CH 2Cl 2 ( 1·2CH 2Cl 2) and [Au 2(μ-bitmb) 2](CF 3SO 3) 2·2CH 2Cl 2 ( 2·2CH 2Cl 2) were determined by single crystal X-ray diffraction. The frameworks of the compounds consist of dicationic rectangular heterometallacycles linked by aurophilic interactions along the b axis and edge-to-face C–H⋯π contacts. The latter expand the structures in zigzag fashion along the a axis leading to a 3D assembly. Interactions between the counterions and imidazole rings are also present in all structures. When crystals of 2·2CH 2Cl 2 are subjected to a dynamic vacuum at 90 °C remarkably only 1 mol equivalent of CH 2Cl 2 is removed, but without loss of crystallinity, affording the structure of 2·CH 2Cl 2.