Experimental and theoretical vibrational study of N-carbamoyl-L-proline

The infrared and Raman spectra of N-carbamoyl-L-proline, C6H10N2O3 [(2S)-1-carbamoylpyrrolidine-2-carboxylic acid] were obtained and interpreted with the help of DFT calculations. Six relatively stable molecular conformers were predicted by theory, being one of these similar to the conformer present in the crystal whose X-ray study was already known. The vibrational study was based in that conformer. The experimental vibrational data and assignments were used as basis for the definition of the Scaled Quantum Mechanics (SQM) force field for the molecule. The Potential Energy Distribution (P.E.D.), which revealed the complex nature of many molecular vibrations, and a set of internal force constants were calculated from this SQM force field.