Infrared spectrum, molecular structure and theoretical calculation of 2-pyridone-6-carboxylic acid

The X-ray and infrared spectroscopic analysis of 2-pyridone-6-carboxylic acid are reported. The crystals of investigated molecule belong to P21/c of the monoclinic system, a = 11.714 Å, b = 3.7088Å, c = 18.223Å and β = 123.71°. The molecule is found in the ketonic form. Comprehensive studies of the molecular structures and vibrational frequencies and infrared intensities of the molecule have been performed by using Hartree–Fock, density functional B3LYP and second-order Moller–Plesset MP2 methods with the 6-31G+(d, p) basis set. The calculated geometrical parameters of investigated molecule in gas phase were compared with the experimental X-ray data.