Influence of inert matrixes on the conformational switching of trimethyl phosphate at low temperatures through thermal effects

Abstract

The conformational switching of trimethyl phosphate (TMP) in Ne, Ar, Kr and Xe matrixes was studied using infrared spectroscopy under isolated conditions at low temperatures. In all the inert matrixes, the vapor phase population of ground state C3(G±G±G±) and the higher energy C1(TG±G±) conformers of TMP is preserved during the initial deposition. However, on annealing the inert Ar/Kr/Xe matrixes, the conformational composition of TMP was irreversibly altered. In Ar and Kr matrixes, an interconversion from ground state C3(G±G±G±) to higher energy C1(TG±G±) conformer was observed whereas Xe presents an interesting variation. In Xe matrix, the higher energy C1(TG±G±) conformer completely depopulated with a concomitant increase in the population of the ground state C3(G±G±G±) conformer. In Ne matrix notably, no conformational interconversion was observed. Computations on the conformers of TMP were performed using B3LYP and M06-2X levels of theory with 6-311++G(d,p) and aug-cc-pVDZ basis sets. The effect of inert matrixes was modeled using Self-Consistent Reaction Field (SCRF) methods.