Electrochemistry and [60]fullerene displacement reactions of (dihapto-[60]fullerene) pentacarbonyl metal(0) (M = Cr, Mo, W).
Cyclic voltammetry (CV) measurements on (eta(2)-C(60))M(CO)(5) complexes (M = Cr, Mo, W) in dichloromethane show three [60]fullerene-centered and reversible reduction/oxidation waves. The E(1/2) values of these waves are shifted to positive values relative to the corresponding values of the uncoordinated [60]fullerene in the same solvent. A Jahn-Teller type distortion of the spherical surface of [60]fullerene promoted by [60]fullerene-metal pi-backbonding may explain the observed positive shifts. Lewis bases (L = piperidine and triphenyl phosphine) displace [60]fullerene from (eta(2)-C(60))M(CO)(5) complexes. Analysis of the activation parameters for the metal-[60]fullerene dissociation, the metal-[60]fullerene bond enthalpies (from DFT computations), and metal-solvent (benzene) bond enthalpies (from DFT computations) suggests appreciable solvent contribution to the transition state leading to formation of the intermediate species solvent-M(CO)(5). Appreciable transition state stabilization due to solvation of the intermediate species is inferred for M = Mo and W. For M = Cr, stabilization of the intermediate species due to solvation is not accompanied by the corresponding transition state stabilization.
Igartúa-Nieves
Elvin
E
Organometallic Chemistry Research Laboratory, Department of Chemistry, University of Puerto Rico, P. O. Box 9019, Mayagüez, Puerto Rico 00681-9019.
Ocasio-Delgado
Yessenia
Y
Torres-Castillo
María D L A
MD
Rivera-Betancourt
Omar
O
Rivera-Pagán
José A
JA
Rodriguez
Diana
D
López
Gustavo E
GE
Cortés-Figueroa
José E
JE