Cocrystals with tunable luminescence colour self-assembled by a predictable way

Organic light-emitting materials play an essential part in the field of luminescent materials because of many advantages such as the easy preparation and controllable luminescent properties. The paper shows that intermolecular interactions and luminescent properties of cocrystals can be predicted by the molecular surface electrostatic potential (SEP) of selected π-hole/σ-hole⋯π bonding donor haloperfluorobenzenes and acceptor acenaphthene (AC). Single crystal X-ray diffraction (XRD) data reveals that actual bonding patterns in five cocrystals assembled by haloperfluorobenzenes and AC are in accordance with the predictable bonding patterns. That is, π-hole⋯π bond is major interaction in AC-C10F8, AC-14DBrPB and AC-TBrPB cocrystals, while σ-hole⋯π bond in AC-14DIPB and AC-TIPB cocrystals. The luminescent properties of the cocrystals are affected by the bonding patterns between AC and haloperfluorobenzenes, that is, π-hole⋯π bond leads to weak phosphorescence, while σ-hole⋯π bond results in weak delayed fluorescence and relative strong phosphorescence.