Theoretical study of molecular interactions of sulfur ylide with HSX (X = F, Cl, and Br) molecules

The molecular interactions between sulfur ylide (SY) and HSX molecules (X = F, Cl and Br) were investigated using the MP2 method with the 6-311++G (2d, 2p) basis set. The SY (CH2=SH2) have two reactive sites: CH2 (denoted as C-interaction) and SH2 (S-interaction) that both could interact with three atoms of HSX molecules. The results show that S center dot center dot center dot C, X center dot center dot center dot C, and H center dot center dot center dot C interactions (C-interactions) is preference over the X center dot center dot center dot S, H center dot center dot center dot S, and H center dot center dot center dot X interactions. Quantum theories of atoms in molecules and natural bond orbitals methods have been applied to analyze the intermolecular interactions. Good correlations have been found between the interaction energies, the second-order perturbation energies E-(2), and the charge transfer qCT in the studied systems.