Crystal and molecular structure of di-µ-carbonyl-carbonyl[carbonyl-(2,3-dimethylbuta-1,3-diene)cobalt]-(π-methylcyclopentadienyl)iron

Abstract

The crystal structure of the title compound has been determined by X-ray diffraction methods by Patterson and Fourier methods from counter data, and refined by least squares to R 0·072 for 3066 unique reflections. The monoclinic unit cell, space group C2/c, has dimensions a= 17·700 ± 0·016, b= 7·404 ± 0·014, c= 23·861 ± 0·040 Å, β= 95·5 ± 0·1°, for Z= 8. The dimer molecule has an almost planar Fe(CO)₂Co bridging system; Fe ⋯ Co is 2·546(1)Å. The metal–bridge-carbon distances are not equivalent [Fe–C 1·897(6) 1·916(6), Co–C 1·966(7) and 1·933(6)Å]. The butadiene is in a cis-configuration and is planar. The C–C distances of the butadiene are equal, mean 1·42(1)Å. The cyclopentadienyl ligand is also planar with equal C–C distances round the ring, mean 1·41(1)Å.