Infrared and Raman analyses of the halogen-bonded non-covalent adducts formed by alpha,omega-diiodoperfluoroalkanes with DABCO and other electron donors

An attractive intermolecular interaction which has been called "halogen bon ding" exists between the nitrogen, sulfur, or oxygen atoms present in HC mo tifs and the iodine atom of PFC residues. The "halogen bonding" is strong e nough to overcome the low affinity existing between PFC and HC compounds, d riving their self-assembly into supramolecular architectures. The non-coval ent co-polymer formed by 1,2-diiodotetrafluoroethane with diazabicyclooctan e has been prepared and characterised by FT-IR and -Raman spectroscopies. W e propose the changes shown by the vibrational spectra of single PFC and HC components when involved in halogen bonded co-polymers as diagnostic probe s of the interaction and as tools to rank the electron-donor ability of dif ferently heteroatom substituted hydrocarbons. (C) 2000 Elsevier Science B.V . All rights reserved.