Topological studies of electron density on the halogen-bond between furan and dihalogen molecules

Theoretical studies on the halogen-bond in complexes of furan and dihalogen molecules (CIF, BrF and BrCI) have been carried out at the level of DFT and MP2(full). The calculated results indicate that the interaction in Y-X center dot center dot center dot pi is stronger than that in Y-X center dot center dot center dot O. The strengths of halogen-bond decrease in the order of furan-BrF>furan-CIF>furan-BrCl. For the two types of halogen-bonded complexes, the formation of halogen bond results in an elongation of X-Y bond, which is accompanied by a red-shift of stretching frequency of the X-Y bond. In addition, the topological properties of the halogen bond have been investigated by the topological analysis of electron density.