Assignment of vibrational spectra of some dialkylamido-derivatives of boron

Abstract

A number of inconsistencies and errors in previous vibrational assignments for molecules containing B–NR₂ groups have been corrected. This was achieved by studying the i.r. and Raman spectra of B(NR₂)₃, B[N(CH₂)₄]₃, B(NR₂)₂Br, and B₂(NR₂)₄, where R = Me or Et. The antisymmetric BN stretches were always above 1 500 cm^–1, with the symmetric BN stretches near 1 350 cm^–1. The value of ν(B–B) in the diboron compounds was ca. 1 230 cm^–1. In B(NR₂)₃ there is extensive vibrational coupling between the NR₂ groups.