REDOX CHEMISTRY OF CYCLOPENTADIENYLCOBALT TETRAAZABUTADIENES. CHARACTERIZATION OF 19-ELECTRON ANIONIC COMPLEXES.

Article abstract of DOI:10.1021/ja00327a013

The results of electrochemical and electronic and EPR spectroscopic studies on a series of novel 19-electron anionic complexes derived from reduction and neutral cyclopentadienylcobalt tetraazabutadienes-CpCo(1,4-R//2N//4) (R equals CH//3, C//6H//5, C//6F//5, 2,4-F//2C//6H//3, 2,6-Me//2C//6H//3; Cp equals eta **5-C//5H//5) - are reported. Investigation of the reduction process by cyclic voltammetry reveals a large dependence of the reduction potential on the nature of R. The reduction potentials are minus 1. 53, minus 1. 01, minus 0. 71, minus 0. 97, and minus 1. 31 v, respectively, vs. the NHE in CH//3CN (0. 1 M Bu//4NBF//4). Each anion displays in isotropic EPR spectrum (g equals 2. 16-2. 21) at ambient temperatures characteristic of cobalt-centered radicals (a//i//s//o equals 50-58 G).