An ab initio study of three (ethane-1,2 diol/water) complexes

Three (ethane-1,2 diol/water) complexes have been studied using ab initio calculations at the MP2 level. In two complexes, the ethane-1,2 diol structure is close to its gas phase experimental structure (presence of an intramolecular hydrogen bond HB and the O–C–C–O dihedral angle is gauche) while the intramolecular HB is disrupted by the presence of a water molecule in the third (tGg′a). Computations have shown that most of the experimental observations regarding the solvation of ethane-1,2 diol in water may be reproduced only by considering the tGg′a complex (absence of intramolecular HB, O–C–C–O dihedral angle of 72–74°), which is also more stable than the other two by 2 kcal mol−1.