Influence of transition metals on halogen-bonded complexes of MCCBr∙∙∙NCH and HCCBr∙∙∙NCM' (M, M' = Cu, Ag, and Au).

We have performed quantum chemical calculations for the MCCBr∙∙∙NCH and HCCBr∙∙∙NCM' (M, M' = Cu, Ag, and Au) halogen-bonded complexes at the MP2 level. The results showed that the transition metals have different influences on the halogen bond donor and the electron donor. The transition metal atom in the former makes the halogen bond weaker, and that in the latter causes it to enhance. Molecular electrostatic potential and natural bond orbital analysis were carried out to reveal the nature of the substitution.