Correlatedab initio geometry and vibrational spectra of imidazole and its different forms

Abstract

The equilibrium geometry, rotational constants, and vibrational frequencies for neutral imidazole, the protonated imidazole cation, the deprotonated imidazole anion, imidazole ylide and the imidazole-Li+ complex have been calculated at the second-order MP level with the 6-31G* basis set. The ylide form of imidazole is found to be 32.5 kcal/mot less stable than the neutral form. Infrared spectra predicted at this level of theory reproduce the experimental spectra sufficiently accurately to enable a reliable assignment for cationic, anionic, and ylide forms and to confirm the interpretation of the SERS spectra of imidazole adsorbed on a silver electrode. © 1992 John Wiley & Sons, Inc.