Dihydrogen bonded phenol–borane-dimethylamine complex: An experimental and theoretical study

Continuing with our earlier communication on the dihydrogen bonded phenol–borane-dimethylamine complex [J. Chem. Phys. 113, 9885 (2000)], we report here, the realistic structure of the said complex calculated using density functional theory at B3LYP/6-31++G(d,p) level. The agreement between the experimental and calculated vibrational spectrum for both the N–H and O–H stretching vibrations along with the low-frequency vibrations that appear in combination with O–H stretching, provides the basis for structural assignment. Analysis of the fate of B–H bonds and B–H stretching vibrations upon formation of dihydrogen bond reveals an anomalous behavior of average bond strengthening.