An experimental and theoretical study of molecular structure and vibrational spectra of 3- and 4-pyridineboronic acid molecules by density functional theory calculations

The experimental and theoretical vibrational spectra of 3- and 4-pyridineboronic acids (abbreviated as p3 and p4) were studied. The Fourier transform Raman and Fourier transform infrared spectra of p3 and p4 molecules were recorded in the solid phase. The structural and spectroscopic analysis of the p3 and p4 acids were made by using density functional harmonic calculations. Both p3 and p4 only one form was most stable using B3LYP level with the 6-31G(d), 6-31G(d,p), 6-311G(d), 6-311G(d,p) and 6-311++G(d,p) basis sets. Selected experimental bands were assigned based on the scaled theoretical wavenumbers. Finally, geometric parameters, infrared and Raman bands and intensities were compared with experimental data of the molecules.