Lithium bonding interaction in H₂CY···LiF (Y = O,S) complexes: a theoretical probe

Abstract

Ab initio calculations at 6-31++G(d,p) level have been done on H₂CY···LiF (Y=O,S) complexes choosing ten possible orientations in each complex. The effect of correlation on complex binding energies has been studied via single point MP2 (full) calculations done on 6-31++G(d,p) geometry. Binding energies have been corrected for basis set superposition error. Frequency calculations confirm that H₂CO···LiF and H₂CS···LiF complexes have three and two stable forms, respectively. The most stable form in each complex has been found to have a strong lithium bonding interaction and a secondary hydrogen bonding interaction. NBO analysis has revealed that in this form oxygen donates n_σ lone pair while sulfur donates its n_π lone pair. In yet another stable form of these complexes, mixed donation of π and n_σ electrons have been observed.