Theoretical study of halogen–hydride halogen bonds in F3CL ··· HM (L=Cl, Br; M=Li, BeH, MgH) complexes

Abstract

Quantum chemical calculations have been performed on six halogen–hydride halogen bonded complexes with F3CCl or F3CBr as the halogen donor and metal hydride (HLi, HBeH and HMgH) as the halogen acceptor. At the MP2/6-311++G(d,p) level, the interaction strength spans from 2.62 to 17.68 kJ mol–1. The C–Cl and C–Br bonds are contracted. However, no evident blue shift accompanies this contraction. The H–Li bond is also contracted, but the H–He and H–Mg bonds are lengthened. However, a blue shift occurs for all these bond-stretching vibrations. These properties were analysed using the theory of natural bond orbital (NBO) and atoms in molecules (AIM). A symmetry-adapted perturbation theory (SAPT) analysis was also carried out to unveil the nature of this novel interaction. It is demonstrated that the electrostatic interaction plays a main role in the interaction, although induction and dispersion interactions are also important.