Synthesis of luminescent cocrystals based on fluoranthene and the analysis of weak interactions and photophysical properties.

A series of luminescent cocrystals with fluoranthene (CH) as the fluorophore and benzene-1,2,4,5-tetracarbonitrile (TCNB, CHN), 2,3,5,6-tetrafluorobenzene-1,4-dicarbonitrile (TFP, CFN) and 1,2,3,4,5,6,7,8-octafluoronaphthalene (OFN, CF) as the coformers was designed and synthesized. Structure analysis revealed that these layered structures were due to charge transfer, π-π interactions and hydrogen bonding. Density functional theory (DFT) calculations show that fluoranthene-TCNB and fluoranthene-TFP have charge-transfer properties, while fluoranthene-OFN does not, indicating that fluoranthene-OFN has arene-perfluoroarene (AP) interactions, which was also demonstrated by spectroscopic analysis, which shows that the photophysical properties of luminescent materials can be tuned by forming cocrystals. These results all prove that utilizing supramolecular cocrystals to develop new fluorescent materials is an effective strategy, which has much potential in optoelectronic applications.