Title
Effects of the alkyl group in (dialkylamino)perfluorophenazines on the melting point and fluorescence properties
Author
Siddanagouda Biradar, Yasuhiro Shigemitsu, Yasuhiro Kubota, Kazumasa Funabiki, Hiroyasu Sato, Masaki Matsui
Year
2014
Journal
RSC Advances
Abstract
The alkyl groups in 2-(dialkylamino)- and 2,7-bis(dialkylamino)perfluorophenazines drastically affected the melting point and solid-state fluorescence. 2-(Dialkylamino)- and 2,7-bis(dialkylamino) derivatives such as 2-(dioctylamino)-, 2-(didodecylamino)-, and 2,7-bis(dioctylamino)perfluorophenazines were liquid at ambient temperature, whereas shorter and longer dialkylamino derivatives were solid. 2-(Dioctadecylamino)perfluorophenazine exhibited a fluorescence maximum at 581 nm, being significantly blue-shifted compared with the other derivatives, with the most intense fluorescence quantum yield of 0.29 in the crystalline form. This result is attributed to the isolated dimer-type packing coming from long octadecyl groups. 2-(Dimethylamino)perfluorophenazine showed positive fluorescence solvatochromism due to a large dipole moment in the excited state. The computational analysis of (2-(dimethylamino)perfluorophenazine suggests that the red-shift of the fluorescence maximum in the crystalline form, compared with that in solution, mainly comes from p–p interactions with adjacent molecules. The fluorescence lifetime of 2-(dioctadecylamino)perfluorophenazine was significantly longer compared with 2-(dioctadecylamino)phenazine owing to the aromatic C–F bonds.
Instrument
FP-8600
Keywords
Fluorescence, Solid state, Chemical stability, Materials