Crystal and molecular structure of di-µ-carbonyl-tetracarbonyl-(π-norbornadiene)dicobalt

Abstract

The crystal structure of the title compound has been determined by X-ray diffraction methods by use of counter data, and refined to R 0·049 for 2996 unique reflections by a full-matrix least-squares procedure. The triclinic unit cell, space group P, has dimensions: a= 8·272, b= 9·262, c= 10·183 Å, α= 112·9, β= 101·7, γ= 82·3°, for Z= 2. The molecule approximates to m symmetry and the Co⋯Co distance is 2·531(1)Å. The norbornadiene ligand bonds to one cobalt atom via the carbon–carbon double bonds. The carbon–carbon double bond distance is 1·373(3)Å. The Co(CO)₂Co bridging system is non-planar, the angle between the two Co(CO)Co planes being 135·0°. The Co–C distances in the bridge are not equivalent, those to the cobalt atom bonded to the norbornadiene being 1·871 (3)Å and those to the other cobalt atom being 1·987 (3)Å.