Crystal and molecular structure of µ-lodo-µ-3-phenylcycloheptatrienylbis(dicarbonylruthenium)(Ru–Ru) : a metal complex with a bridging cycloheptatrienyl ligand

Abstract

Crystals of the title compound are monoclinic, space group P2₁/c, with Z= 4 in a unit cell of dimensions: a=8.482(2), b= 13.525(4), c= 15.851(3)Å, β= 94.86(4)°. The structure was determined by heavy-atom methods from diffractometer data and refined to R 0.031 for 2 200 independent reflections. The two ruthenium atoms are bridged by the iodine atom [Ru–Ru = 2.866(1)Å, Ru–I = 2.685(1) and 2.71 1(1)Å]; each Ru atom carries two terminal carbonyl groups orthogonal to one another and to the corresponding Ru–I bond, and eclipsed with respect to the Ru–Ru vector. The C₂ ring is symmetrically related to the plane which bisects the Ru–Ru bond perpendicularly. One carbon atom thus bridges the Ru–Ru bond. while the remaining six comprise two η³-allyl moieties each bonded to the nearer Ru atom. The phenyl substituent is attached to the C atom adjoining the central bridging C atom. The C₇ ring presents a concave face to the Ru–Ru bond. Its mode of attachment is therefore in every respect different from that found in [Ru₂(CO)₅(SiMe₃)(C₇H₈SiMe₃)].