Theoretical studies of molecular structure and vibrational spectra of free, H-bonded and coordinated nicotinamide

► The molecular geometry of three nicotinamide complexes is calculated using the B3LYP/DFT method. ► The vibrational spectra of these complexes are computed at the same level of theory. ► The structure and vibrational spectra of the complexes are compared with the free nicotinamide molecules.