Di-μ-methano-lato-bis-[( 4-tetra-fluoro-benzobarrelene) rhodium(I)]

Abstract

The versatile synthetic precursor methano-late-bridged title rhodium complex, [Rh 2(CH 3O) 2(C 12H 6F 4) 2] or [Rh(-OCH 3)(tfbb)]2 [tfbb = tetra-fluoro-benzobarrelene or 3,4,5,6-tetra-fluoro-tricyclo-[6.2.2.0 2,7]dodeca-2(7),3,5,9,11-penta-ene], has been structurally characterized. The asymmetric unit contains half a mol-ecule that can be expanded via a twofold axis. The title compound has been shown to be a dinuclear rhodium complex where each metal centre is coordinated by two O atoms from two bridging methano-late groups and by the olefinic bonds of a tfbb ligand. Comparison of the bite angles of tfbb, norbornadiene (nbd) and cyclo-octa-diene (cod) olefins in their 4-coordination to rhodium reveals similarities between the tfbb and nbd ligands, which are much more rigid than cod. The short distance found between the distorted square-planar metal centres [2.8351 (4) Å] has been related to the syn conformation of the folded core RhORhO ring. © 2012 International Union of Crystallography.