Rhodocenium Complexes Bearing the 1,2,3-Tri-<i>tert</i>-butylcyclopentadienyl Ligand: Redox-Promoted Synthesis and Mechanistic, Structural and Computational Investigations
作者:Bernadette T. Donovan-Merkert、C. Reid Clontz、Leslie M. Rhinehart、Howard I. Tjiong、Clifford M. Carlin、Thomas R. Cundari、Arnold L. Rheingold、Ilia Guzei
DOI:10.1021/om9707735
日期:1998.4.1
Single-electron oxidation of rhodium complexes containing the 1,2,3,5-eta-penta-2,4-dienediyl ligand was conducted by electrochemical and chemical means. In all cases, rhodocenium complexes bearing the eta(5)-1,2,3-tri-tert-butylcyclopentadienyl ligand were produced in good yield. The results of single-crystal X-ray diffraction studies revealed the solid-state structures of [Rh(eta(5)-C5H5)(eta(5)-(C5Bu3H2)-Bu-t)][PF6] (10a(+)) and [Rh(eta(5)-C5H5)(eta(5)-(C5Bu3H2)-Bu-t)][BF4] (10b(+)), The steric strain in these molecules is apparently relieved by in-plane distortions of the bond lengths and angles of the tri-tert-butylcyclopentadienyl ligand. The results of a deuterium-labeling study revealed the stereochemistry of the ring-closure reaction. Computational studies using the PM3 semiempirical Hamiltonian suggest that oxidation of the pentadienediyl complexes involves removal of an electron from a molecular orbital centered on the pentadienediyl Ligand.