Spectroscopic studies on organometallic compounds. Part XI. Infrared spectra of pentacarbonyl complexes of metals of the chromium and manganese sub-groups in the carbonyl stretching region

Abstract

An analysis has been made of the carbonyl stretching frequencies of complexes of formula LM(CO)₅[M = Cr, Mo, or W, with L = R₃E (E = P, As, Sb, or Bi; R = Ph, Me, MeO, Cl, or F); and M = Mn or Re, with L = R₃M (M = Si, Ge, Sn, or Pb; R = Ph, Me, Cl, or Br)]. Band assignments and approximate force constants were obtained using CO stretch–stretch interaction relationships derived from elementary bonding considerations. Where expedient certain assignments were made by comparison with closely related derivatives. The force constants obtained parallel the relative energies of the two lowest observed frequencies.