Tuning the solid-state emission by co-crystallization through σ- and -hole directed intermolecular interactions

Four new binary luminescent co-crystals and a co-crystal stoichiomorph comprising aromatic compounds and 1,4-diiodotetrafluorobenzene were successfully synthesized by the solvent drop grinding method. Structural features of these co-crystals indicate that the relative interplay of sigma- and -hole directed intermolecular interactions were observed to be responsible for modulating luminescence properties of those materials. Investigation of photoluminescence properties reveals that there is a substantial change in emission color from the starting aromatic materials to co-crystals. The IN and sigma-hole halogen bonds along with -hole interactions have been instrumental towards altering the emissive properties of the luminescent materials.