Structure and interactions in reline (1:2 Choline chloride – Urea mixture) according to quantum chemical calculations and molecular dynamics simulation

Abstract

Quantum chemical calculations using the B3LYP + GD3/6–311++g(2d,2p) method were carried out to study the structure and interactions in a number of complexes containing a choline cation, a chloride anion and urea molecules. The contributions from Coulomb and van der Waals interactions were calculated. The QTAIM method was used to evaluate the strength of various bonds in these complexes. A molecular dynamics simulation of reline was also carried out in the NPT ensemble at a pressure of 1 atm and at temperatures of 298 and 323 K, with the GAFF force field and charges taken from our quantum chemical calculations. The particle radial distribution functions of centers of mass, local mole fraction functions, atom–atom radial distribution functions, and spatial distribution functions were calculated. Particles of different types were shown to form bonds of different types competing with each other.