Chromium tricarbonyl complex of phosphaalkene: Crystal structure and electrochemistry of the Cr(CO)3 complex of PhC(H)double bond; length as m-dashPMes*, EPR and DFT studies of its radical anion

We report the synthesis, crystal structure and electrochemical behaviour of a complex in which the Ph group of the phosphaalkene PhC(H)double bond; length as m-dashPMes* (Mes*: 2,4,6-tri-tert-butylphenyl) is coordinated to a chromium tricarbonyl group. The EPR spectra resulting from electrochemical and chemical reductions are described and the experimental g and hyperfine tensors (31P)T, as determined from the EPR data, are compared with those predicted by DFT calculations for the radical anion (Cr(CO)3, PhC(H)double bond; length as m-dashPMes)radical dot−. The structural changes caused by the addition of an electron to the neutral complex are described, together with an estimation of the contribution of Cr(CO)3 to the stabilization of the radical anion.