Halogen bonds with coordinative nature: halogen bonding in a S-I+-S iodonium complex

A detailed study of unexpectedly strong iodonium-sulfur halogen bonds in [I(2-imidazolidinethione)(2)](+) is presented. The interactions are characterized by single-crystal X-ray diffraction, charge density analysis based on QTAIM calculations, mass spectrometry, and NMR spectroscopy. The results, small R-IS = 0.7 and high interaction energy of 60 kJ mol(-1), support a coordinative nature of the halogen bond between the iodonium ion and the sp(2) hybridized sulfur atoms.