Stereochemistry of cobalt complexes with heteronuclear metal–metal bonds: the crystal and molecular structure of tetracarbonyl(triphenylphosphineaurio)cobalt, and of tetracarbonyl{[bis-(o-dimethylarsinophenyl)methylarsine]argentio}cobalt

Abstract

Single-crystal X ray structure analyses of tetracarbonyl(triphenylphosphineaurio)cobalt and of tetracarbonyl{[bis-(o-dimethylarsinophenyl)methylarsine]argentio}cobalt are reported. In both compounds the cobalt atom is five-co-ordinated in a trigonal bipyramidal stereochemical form, which has a gold or silver atom in an apical position, and is distorted by bending of the three equatorial carbonyl groups towards the metal atom at the apex. The gold atom has an almost linear two-co-ordination with a gold–phosphorus bond length of 2·23(2)Å. The silver atom has a distorted tetrahedral arrangement of bonds. Metal–metal bond lengths are Au–Co 2·50(1) and Ag–Co 2·66(1)Å.