Preparation and redox properties of phosphite derivatives of R2C2Co2(CO)6-n[P(OMe)3]n (R = CF3, MeO2C)

A series of phosphite complexes R2C2Co2(CO)(6-n)[P(OMe)(3)](n) (R = CF3, MeO2C), n = 1-4, have been prepared and characterised. Cyclic and square-wave voltammetry shows that the kinetic stability of the radical cations increases with substitution and when R=CF3. The radical cation {(CF3)(2)C2Co2(CO)(2)[P(OMe)(3)](4)}PF6 4a(+) has been characterised and its crystal structure compared with that of the neutral parent. Analysis of the anisotropic ESR spectrum of 4a(+) is consistent with an unpaired electron in a SOMO with little d(z)(2) character. (C) 1998 Elsevier Science S.A. All rights reserved.