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

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.