Theoretical analysis of the spodium bonds in HgCl2•••L (L = ClR, SR2, and PR3) dimers

Halogen bonds have received increasing interest in non-covalent interactions. Recently, a new kind of noncovalent interaction, spodium bond, was proposed to refer to a net attractive interaction between any element of group 12 and electron rich atoms. Due to strong relativistic effect, Hg is much different from the other group 12 elements, which prefers more linear coordination. Thus, we theoretically studied the model of HgCl2 center dot center dot center dot L, (where L = ClR, SR2, PR3 families) to explore the nature of the linear coordinated spodium bonds. Analyses of electrostatic potential surfaces, together with ELF, LOL, and chemical bonding analyses, suggest the presence of covalent interaction. Complexes with nitrogen, oxygen, and fluorine donors result in more coulombic component, whereas others are dominated by covalent interaction, indicating coexistence of coulombic and covalent interaction. Besides, covalent interaction is significantly stronger with phosphorus donor. This model can provide intriguing perspectives for future weak intermolecular interactions studies.