Simultaneous Interaction of Tetrafluoroethene with Anions and Hydrogen-Bond Donors: A Cooperativity Study

A computational study of the complexes formed by tetrafluoroethylene, C2F4, with anions has been carried out by means of density functional theory (DFT) and second-order Möller-Plesset (MP2) computational methods, up to MP2/aug-cc-pVTZ level. In addition, the possibility of cooperativity in the interaction of anions and hydrogen-bond donors (FH, ClH, and H2O) when interacting with different faces of the C2F4 molecule has been explored. Electron density of the complexes has been analyzed by means of atoms in molecules (AIM) methodology, while natural bond orbital (NBO) methodology has been used to characterize the orbital interaction. In addition, natural energy decomposition analysis (NEDA) has been applied to analyze the source of the interaction. The energetic results indicate that C2F4 is a weaker anion receptor than C6F6, but in combination with the anions, it became a stronger hydrogen acceptor than C2H4. Cooperativity effects are observed in YH·C2F4·X(-) clusters. In C2F4·X(-) complexes the dominant attractive terms are the electrostatic and polarization ones, while in YH·C2F4·X(-) complexes the charge transfer increases significantly, becoming the most important term for most of the FH and ClH complexes studied here.