Electroinduced and spontaneous metal-halide bond dissociation in [Co(eta(5)-C5H5)(eta(3)-2-MeC3H4)I]

Teixeira, M. G., F. Paolucci, M. Marcaccio, T. Aviles, C. Paradisi, F. Maran, and S. Roffia. "Electroinduced and spontaneous metal-halide bond dissociation in [Co(eta(5)-C5H5)(eta(3)-2-MeC3H4)I]." Organometallics. 17 (1998): 1297-1304. copy at https://docentes.fct.unl.pt/p387/publications/electroinduced-and-spontaneous-metal-halide-bond-dissociation-coeta5-c5h5eta3-2-me


The electrochemical behavior of the species [Co(eta(5)-C5H5)(eta(3)-2-MeC3H4)I] and [Co(eta(5)-C5H5)(eta(3)-2-MeC3H4)(ACN)](+) in ACN solutions, at 25 degrees C, is described. The kinetic analysis of the cyclic voltammetry curves indicates that the introduction of one electron in the former complex is concerted with the dissociation of the Co-I bond. The ensuing radical undergoes fast solvation to yield the solvato complex [Co(eta(5)-C5H5)(eta(3)-2-MeC3H4)(ACN)](.), which then acts as an efficient electron donor toward the starting material with the formation of[Co(eta(5)-C5H5)(eta(3)-2-MeC3H4)(ACN)](+); finally, the cation is electroreduced at the working potentials to conclude an overall autocatalytic sequence. The solvato complex [Co(eta(5)-C5H5)(eta(3)-2-MeC3H4)(ACN)](.), formed as a product of the above reduction process, can be reversibly reduced to the corresponding anion at more negative potentials. Confirmation of the above mechanism and of the fact that the solvato complex can act as a solution electron donor toward the starting material was obtained by studying the electrochemical behavior of the solvato complex itself and through calculations aimed to better define the dissociative electron-transfer process to [Co(eta(5)-C5H5)(eta(3)-2-MeC3H4)I]. The dissociation of the metal-halide bond in the neutral complex [Co(eta(5)-C5H5)(eta(3)-2-MeC3H4)I], with the formation of[Co(eta(5)-C5H5)(eta(3)-2-MeC3H4)(ACN)](+), was also found to occur spontaneously, in the bulk, through the observation of a progressive change of the cyclic voltammetric pattern. Support for the occurrence of the reaction between the starting complex and the solvent was confirmed by conductivity and spectroscopic measurements, which allowed the rate constant for the homogeneous solvolysis to be determined.


Zg590Times Cited:3Cited References Count:37

Related External Link