Matrix infrared spectroscopic and ab initio investigations of methylcarbamate dimer and methylcarbamate-water complex

• First infrared work on CH 3 CO 2 NH 2 dimer and CH 3 CO 2 NH 2 H 2 O complexes in solid. • Complementarity of ab initio calculations and experiment to perform analysis. • Hydrogen bonding between water and CH 3 CO 2 NH 2 . For the first time the experimental study of the complexation of methylcarbamate (CH 3 CO 2 NH 2 ) molecule with water has been undertaken from a vibrational point of view as well as the homodimer (CH 3 CO 2 NH 2 ) 2 in solid neon at 3 K from 80 to 6000 cm −1 using Fourier transform infrared spectroscopy. From concentration effects and with the help of theoretical calculations we have identified several vibrational transitions for methylcarbamate dimer and methylcarbamate-water complexes with one and two water molecules. In the methylcarbamate-water complex the two molecules interact through hydrogen bonding where the water plays the role of the proton donor to one of the two oxygen atoms of methylcarbamate and the NH 2 of the amide group is also a proton donor to the oxygen of water. From the vibrational data we highlight the presence of two isomers. Theoretical calculations at the second-order Møller-Plesset (MP2) level have been performed to obtain the equilibrium geometries and vibrational spectra at the harmonic level of the most stable complexes and comparison with experimental data allows us to confirm the structures of the complexes.