Insight into the halogen-bonding interactions in the C6F5X···ZH3 (X = Cl, Br, I; Z = N, P, As) and C6F5I···Z (Ph)3 (Z = N, P, As) complexes

Abstract

The ability of C6F5X (X = Cl, Br, I) to favorably interact with ZH3 (Z = N, P, As) was evaluated at the level of M06-2X functional. For comparison, the C6F5I···ZPh3 (Z = N, P, As) complex was also studied. The halogen bond donors C6F5X (X = Cl, Br, I) have positive regions of electrostatic potentials (ESP) outside the X atom, and could interact with the negative ESP outside the Z atom of ZH3 (Z = N, P, As) to form the X···Z halogen bond. When the halogen bond donor remains unchanged, the halogen bond strength grows along the decreasing size of As, P, and N. When halogen bond acceptor remains unchanged, the halogen bond becomes stronger gradually along the sequence of X = Cl, Br, I. It was found that C6F5I···ZPh3 complex greatly reduces the strength of the halogen bond comparing with the C6F5I···ZH3.