A cyclooctatrienone complex of diiron hexacarbonyl

Abstract

In the title compound, [μ-(2,6,7-η:3,4,5-η)-cycloocta-2,4,6-trienone]bis(tricarbonyliron)(Fe—Fe), [Fe2(C8H8O)(CO)6], the diiron hexacarbonyl moiety has a sawhorse arrangement, with the OC—Fe—Fe—CO fragment forming the horizontal bar of the horse, and the other four carbonyl groups the legs. The Fe—Fe distance is 2.795 (2) Å. Each Fe atom is also bonded to three C atoms of the cyclooctatrienone ring. One Fe atom forms a σ-bond with one ring C atom, with Fe—C = 2.109 (2) Å, and also a metal–olefin π-bond with two C atoms on the other side of the ring, with Fe—C distances of 2.238 (2) and 2.236 (3) Å. The second Fe atom forms a η3-allyl bond with three other ring atoms, with Fe—C bond lengths of 2.158 (2), 2.062 (2), and 2.123 (3) Å. Counting the π- and π-allyl interactions as one bond, the coordinations of the Fe atoms can, respectively, be approximated as octahedral and trigonal bipyramidal.