Vibrational spectroscopy and analysis of pseudo-tetrahedral complexes with metal imido bonds

The mononuclear iron(III) and cobalt(III) imido complexes of the monoanionic tridentate ligand [PhB[P.sub.3]] ([PhB[P.sub.3]] = [[PhB(C[H.sub.2]PP[h.sub.2])[.sub.3]][.sup.-] were examined to clarify the vibrational features for these trivalent metal imides. The degree of coupling to the ancillary organic group appears higher in the aryl imides than in the alkyl imides, but in both cases, isotope labeling was utilized to arrive at the modes with the greatest degree of metal-nitrogen stretching character.