Synthesis, structure and density functional study of the ansa-rhenocene complex [Re{(eta-C5H4)CMe2(eta-C5H4)}Cl]

The ansa-rhenocene compound [Re{(eta-C5H4)CMe2(eta-C5H4)}Cl] 1 has been pre pared by reaction of ReCl5 with [K-2(C5H4)CMe2(C5H4)]. X-Ray crystallograph y shows the molecular structure to be unsymmetrical, with the angle defined by the Re-bridgehead carbon vector and the chlorine atom found to be 170.4 degrees. A density functional study compares the electronic structure of [ Re{(eta-C5H4)CH2(eta-C5H4)}Cl] with [Re{(eta-C5H5)(2)Cl] and shows that for the ansa-bridged species, the chlorine binds less effectively in the centr al position. The calculated structure of [Re{(eta-C5H4)CH2(eta-C5H4)}Cl] is also found to be unsymmetrical.