Vibrational spectra and structures of the 1:1 complexes of niobium and tantalum, pentachlorides and tantalum pentabromide with aceto-, perdeuterioaceto-, and propio-nitriles in the solid and solution states and a vibrational analysis of the species MX5,NC·CY3(Y = H or D)

Abstract

The low-frequency i.r. and Raman spectra of the title compounds are shown to be essentially identical in the solid state and in solution in acetonitrile. The vibrational spectra taken in conjunction with conductivity and molecularweight data, provide conclusive evidence that they are all monomolecular and may be formulated as MX₅,RCN. The vibrational assignments are supported by normal co-ordinate calculations for a C_4v model MX₅,NC·CY₃, where free rotation of the CY₃ group (Y = H or D) is assumed.