Proton Magnetic Resonances of Some Borazole Derivatives

Abstract

The proton magnetic resonance spectra of ten borazole derivatives were recorded and assignments were carried out. The chemical shifts of BH and NH protons are close to each other, the values being nearly equal to the sum of the contribution of a diamagnetic ring current and the chemical shift of C=CH–C protons. The signals of NH and BH protons showed the partial collapse of multiplet structures due to quadrupole relaxation. BC2H5 protons gave a single sharp line instead of showing both methyl and methylene signals each split by I–I coupling. An explanation is given in terms of electronegativity considerations.