Structure of an iron–cobalt organometallic complex. Crystal and molecular structure of di-µ-carbonyl-carbonyl[dicarbonyl(methyldiphenylphosphine)cobaltio]-π-cyclopentadienyliron

Abstract

The crystal structure of the title compound has been determined by three-dimensional photographic X-ray diffraction methods and refined to R 0·085 for 1466 unique reflections by least-squares procedures. The triclinic unit cell, space group P, has dimensions: a= 6·948 ± 0·009, b= 11·551 ± 0·018, c= 14·618 ± 0·019 Å, α= 100·9, β= 86·9, γ= 104·3°(all ±0·1°), for Z= 2. The molecule shows no overall symmetry and possesses two bridging carbonyl groups, with Fe ⋯ Co 2·540 (4)Å. The Fe(CO)₂Co bridging system is non-planar with the π-cyclopentadienyl ring trans to the puckering. The angle between the two bridging Fe–C–Co planes is 25·4°. The carbon atoms of the π-cyclopentadienyl ring are displaced equally from the Fe atom, mean distance 2·11 Å. The Fe–C and Co–C distances in the carbonyl bridge are not equivalent: Fe–C(1) 1·797(16), Fe–C(2) 1·967(19), Co–C(1) 2·027(20), Co–C(2) 1·907(17)Å, and indicate a trans-influence of the methyl(diphenyl)phosphine group. Co–P is 2·221(6)Å.