Conformation equilibrium of 3-(hydroxymethyl)piperidine in solvents with different polarity

Quantum-chemical calculations of the 3-(hydroxymethyl)piperidine molecule conformers were performed at the B3LYP/6-31+G** level of theory, and four most stable conformations with different relative orientation of CH₂OH and N–H groups were determined. The optimized structures, vibration frequencies, and band intensities in the spectra of the conformers were obtained. The conformational equilibria of the most stable rotational isomers in solvents of different polarity was studied within the polarizable continuum model. According to the results of calculations, the conformational equilibrium in solution is substantially changed on varying the solvent polarity. This conclusion was confirmed by comparison with IR absorption spectra of 3-(hydroxymethyl)piperidine solutions in carbon tetrachloride in the region of ОН-stretchings.