Synthesis And Optical Properties Of Molecular Cocrystal Materials

Adjusting and controlling the solid-state photophysical properties of molecule-based fluorophores are attracting more and more attention due to the potential applications in laser,chemical sensors and information storage.Multi-component molecular solids have the advantages of easy processing and highly tunable structures,which facilitate the construction of flexible optical films.Thus,construction of luminescent cocrystals of a target fluorophore is crucial to develop new-generation light-emitting materials.In this work,based on the design principle of molecular self-assembly,9-acetylanthracene and 4-[2-(4-quinolinyl)vinyl]phenol were chosen as typical fluorescent model systems,five cocrystals have been synthesized by selecting co-assembled units with different potential non-bonding interactions(such as halogen-/hydrogen-bonds and ?-? interactions)between the molecules.By the combination of experimental and theoretical studies,the molecular cocrystals present wide-range tunability of luminescence properties(such as wavelength,color,fluorescence lifetime,photoluminescence quantum yield and two-photon emission)relative to single component.In addition,aggregation induced emission(AIE)can be further obtained for 9-acetylanthracene and 1,2,4,5-tetracyanobenzene cocrystal,which is as an alternative to the traditional aggregation caused quenching(ACQ).Furthermore,the acid-stimuli luminescence enhancement and fluorescent acid-base switching behaviors can be obtained for 4-[2-(4-quinolinyl)vinyl]phenol-tetrafluoroterephthalic acid cocrystal.Such adjusting optical behaviors not only open a way in the fields of light emitting,chemical sensor and security,but also provide a detailed understanding of the molecule structure-property relationship.