Crystal and molecular structure of cis-di-µ-carbonyl-bis[carbonyl-(π-cyclohexa-1,3-diene)cobalt]

Abstract

The crystal structure of the title compound has been determined by photographic X-ray diffraction methods and refined to R 0·091 for 690 unique reflections by a full-matrix least-squares procedure. The orthorhombic unit cell, space group Cmcm, has dimensions a= 10·041, b= 7·880, c= 18·881 Å, for Z= 4. The dimer molecule has symmetry mm(a requirement of the space group) with an almost planar Co(CO)₂Co bridging system: Co⋯Co is 2·559 Å. The cyclohexadiene ligands bond to the cobalt atoms via butadiene fragments with Co–C(butadiene) 2·04 and 2·13 Å. The C–C distances of the butadiene fragments are equal, mean 1·40 Å.