Observation of a two-dimensional halogen-bonded cocrystal at sub-monolayer coverage using synchrotron X-ray diffraction.

The formation of two-dimensional halogen-bonded layers of 4,4'-bipyridyl and 1,4-diiodotetrafluorobenzene was observed on a graphite surface at sub-monolayer coverage using synchrotron X-ray diffraction; the use of the diffraction technique enabled, for the first time, the measurement of I···N halogen bonding distances in a two-dimensional cocrystal and the identification of the halogen bonding interaction in the monolayer.