Organobismuth(V) compounds. Part VII. Preparation, characterization, and vibrational spectra of four- and five-co-ordinate tetraphenylbismuth(V) derivatives

Abstract

New tetraphenylbismuth(V) compounds Ph₄BiX (X = BF₄, PF₆, NCO, NCS, and CCl₃CO₂) have been prepared. These compounds, together with the previously known Ph₄BiClO₄ and Ph₄BiN0₃, have been studied Oby i.r. and laser Raman spectroscopy and by molecular-weight and conductance measurements. The vibrational spectra and conductance data for the derivatives, where X = ClO₄, BF₄, or PF₆, are consistent with an ionic constitution. The nitrate, trichloroacetate, thiocyanate, and cyanate compounds are indicated to be non-ionic, containing five-co-ordinate bismuth. Molecular-weight data for the nitrate and trichloroacetate compounds, in benzene, are also in accord with a five-co-ordinate structure; the thiocyanate and the cyanate compounds decompose in benzene. Assignments for vibrational frequencies associated with the Bi–Ph bonds for the ionic and five-co-ordinate derivatives are discussed.