Di-μ-methanolato-bis[(η4-tetrafluorobenzobarrelene)rhodium(I)]

Abstract

The versatile synthetic precursor methanolate-bridged title rhodium complex, [Rh(2)(CH(3)O)(2)(C(12)H(6)F(4))(2)] or [Rh(μ-OCH(3))(tfbb)](2) [tfbb = tetrafluorobenzobarrelene or 3,4,5,6-tetrafluorotricyclo[6.2.2.0(2,7)]dodeca-2(7),3,5,9,11-pentaene], has been structurally characterized. The asymmetric unit contains half a molecule 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 methanolate groups and by the olefinic bonds of a tfbb ligand. Comparison of the bite angles of tfbb, norbornadiene (nbd) and cyclooctadiene (cod) olefins in their η(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.