Crystal and molecular structure of cis-(isobutyl isocyanide)di-µ-carbonylcarbonylbis(π-cyclopentadienyl)di-iron

Abstract

The crystal structure of the title compound has been determined by the heavy-atom method from X-ray diffraction counter data and refined to R 0·072 for 1447 unique reflections by a full-matrix least-squares procedure. The orthorhombic unit cell, space group P2₁2₁2₁, has dimensions a= 6·649 ± 0·011, b= 13·062 ± 0·035, c= 20·553 ± 0·052 Å, for Z= 4. The complex has a cis-configuration with a non-planar Fe(CO)₂Fe bridging system, the angle between the two Fe(CO)Fe planes being 165·6°. The isocyanide ligand is terminal to one Fe, and has a linear Fe–C–N–C grouping. The distances from the iron atoms to the bridge-carbon atoms are equivalent, mean 1·91 Å. The distance of the iron atom to the terminal carbonyl carbon atom is 1·745(16)Å and to the isocyanide carbon atom 1·846(15)Å, Fe ⋯ Fe 2·524(3)Å.