Halogen bonding in a multi-connected 1,2,2-triiodo-alkene involving geminal and/or vicinal iodines: A crystallographic and DFT study

Four halogen-bonded arrangements of (1,2,2 - triiodovinyl) benzene involving geminai and/or vicinal iodine atoms were studied both by X-ray diffraction and density functional theory (DFT). Crystallographic data show weaker XB-type interactions for the iodine atom geminal to the phenylring, which is corroborated by DFT-optimized structures of 1:1, 1:2 and 1:3 (1,2,2-triiodovinyl)benzene/pyridine complexes. In addition, a theoretical model reflects an interplay existing between these conjugated and multi-connected sites, highlighting the weakening of the halogen bonds when the number of partners is increased. © The Royal Society of Chemistry 2016