Cocrystals with tunable luminescence colour self‐assembled by a predictable method

Organic light-emitting materials play an essential role in the field of luminescent materials because they are easily prepared and they have controllable luminescent properties. Here it is shown that intermolecular interactions and luminescent properties of cocrystals can be predicted using the molecular surface electrostatic potential of selected π-hole/σ-hole⋯π bonding donor haloperfluoro­benzenes and acceptor acenaphthene (AC). Single-crystal X-ray diffraction data reveal that actual bonding patterns in five cocrystals assembled from haloperfluoro­benzenes and AC are in accordance with predictable patterns of intermolecular interactions; that is π-hole⋯π bond is the major interaction in AC–octa­fluoro­naphthalene, AC–1,4-di­bromo­tetra­fluoro­benzene and AC–1,3,5-tri­bromo-2,4,6-tri­fluoro­benzene cocrystals, whereas σ-hole⋯π bond is the major interaction in AC–1,4-di­iodo­tetra­fluoro­benzene and AC–1,3,5-tri­fluoro-2,4,6-tri­iodo­benzene cocrystals. The luminescent properties of the cocrystals are affected by the bonding patterns between AC and haloperfluoro­benzenes; the π-hole⋯π bond leads to weak phospho­rescence, whereas the σ-hole⋯π bond results in weak delayed fluorescence and relatively strong phospho­rescence.