The hyperfine structure of electron spin resonance spectrum of tricobalt cluster radical anion CH3CCo3(CO)

CH₃CCo₃(CO)₉ was synthesized from the reaction between chloralose and Co₂(CO)₈. The radical anion was generated by electrochemical reduction, and electron spin resonance spectra in THF were recorded by in situ electrolysis in the sample tube in the ESR cavity at 298 and 110K with the spectral data <g> =2.015, g =2.013, g =2.016; <a> = —35.2G, a₁ = —78.6G and a =—13.5G. The effect on shift of the magnetic resonance field by using the second order perturbation theory was discussed, and the electron spin density on Co atom orbitals 4s, 4p and 3d was calculated, respectively to be 4s: —0.08, 3d: 0.855 and 4p: 0.225.