Understanding relationship between stacking modes and optical properties of organic charge transfer cocrystals involving anthracyl chalcones and TCNB

Abstract

Four charge transfer (CT) cocrystals with different molar ratio were obtained via self-assembly process, involving 3-(9-anthryl)-1-phenyl-2-Propen-1-one (APPO), 3-(9-anthryl)-1-(4-methoxyphenyl)-2-Propen-1-one (AMPO), 3-(9-anthracenyl)-1-(1-naphthalenyl)- 2-Propen-1-one (ANPO) as electron donors and 1,2,4,5-tetracyanobenzene (TCNB) as electron acceptor. Crystal structure analysis demonstrates that two types of face-to-face patterns (D···A···D···A···D and DAD···DAD) were mainly formed via π···π interactions. X-ray diffraction, vibration spectroscopy, thermal behaviors, solid-state absorption spectroscopy and fluorescence properties were employed to assess the relations between their structures and performance. Remarkably, the fluorescent characteristics of the cocrystals showed significant increase relative to pristine donors, which was induced by the charge-transfer interactions between donors and acceptor molecules. These results evidently contribute to better cognizance of relationship between stacking modes and optical properties in CT cocrystals.