Infrared Spectroscopy of Hydrogen Bonding Interactions in Neutral Dimethylamine-Methanol Complexes.

Infrared spectra of the neutral dimethylamine-methanol cluster, DMA-CH3OH, were measured in the spectral range of 2800-3900 cm(-1) using an infrared-vacuum ultraviolet (IR-VUV) scheme. Quantum chemical calculations and ab initio molecular dynamic (AIMD) simulations were carried out to understand the experimental spectral features. Experimental and theoretical results reveal the coexistence of N center dot center dot center dot HO and O center dot center dot center dot HN hydrogen-bonded structures. AIMD simulations show that the methyl group in methanol internally rotates around the N center dot center dot center dot O axis, addressing the dynamic effect of the fluctuation of hydrogen bonds on the vibrational features. The bonding analysis was performed to elucidate the nature of the intermolecular interaction between DMA and CH3OH. The present work provides the fundamental understanding of hydrogen-bonding networks in the amine-alcohol complexes.