名称:
Rhodocenium Complexes Bearing the 1,2,3-Tri-tert-butylcyclopentadienyl Ligand: Redox-Promoted Synthesis and Mechanistic, Structural and Computational Investigations
摘要:
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.