Perfluorocarbon-hydrocarbon self-assembly: First crystalline halogen-bonded complex involving bromoperfluoroalkanes

The N...Br halogen bonding effectively drives the intermolecular recognition between bromoperfluoroalkanes and nitrogen substituted hydrocarbons in the liquid and solid phases. The interaction is strong enough to control the self-assembly of N,N,N'N'-tetramethyl-p-phenylenediamine and 1,8-dibromoperfluorooctane into a cocrystal that is solid and stable at room temperature in air. The first single-crystal X-ray structure of a complex containing bromomoperfluoroalkanes is reported. One-dimensional infinite chains are formed where the two modules alternate. The low affinity that perfluorocarbon derivatives have for hydrocarbon compounds controls the packing of these chains and leads to the formation of a cocrystal where perfluorocarbon and hydrocarbon layers alternate. Bromoperfluoroalkanes are thus new tectons for the formation of hybrid perfluorocarbon-hydrocarbon crystalline materials.