1H–pyrazole–3–carboxylic acid: Experimental and computational study

Abstract

The FT–IR and UV–Vis spectra for 1H–pyrazole–3–carboxylic acid (H2pc) were recorded in methanol solvent. The optimized molecular structure, vibrational frequencies and NMR chemical shifts of the title molecule in methanol solvent and gas phase were obtained by using DFT/B3LYP and DFT/HSEh1PBE methods with 6–311++G(d,p) basis set. TD–DFT calculations in methanol solvent and gas phase were used to investigate UV–Vis absorption wavelengths. Furthermore, the NLO parameters and FMO energies of the molecule were calculated by using B3LYP and HSEh1PBE methods with 6–311++G(d,p) basis set. In order to investigate intermolecular hydrogen bonds and π–π interactions, NBO study was fulfilled by the same levels. To sum up, the fact that the title compound used frequently in coordination chemistry field has encouraged us to do experimental and theoretical characterizations of H2pc