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Optical and Photosensitizing Properties of Spiro(dipyridinogermole)(dithienogermole)s with Eletron‐Donating Amino and Electron‐Withdrawing Pyridinothiadiazole Substituents
Author(s) -
Ohshita Joji,
Hayashi Yuya,
Adachi Yohei,
Enoki Toshiaki,
Yamaji Kosuke,
Ooyama Yousuke
Publication year - 2018
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201801031
Subject(s) - solvatochromism , triphenylamine , chemistry , quantum yield , photosensitizer , conjugated system , photochemistry , polar effect , tetraphenylporphyrin , singlet oxygen , chloroform , solvent , medicinal chemistry , photoluminescence , porphyrin , fluorescence , oxygen , organic chemistry , materials science , physics , optoelectronics , quantum mechanics , polymer
Abstract Three spiro(dipyridinogermole)(dithienogermole) (sDPyG) derivatives with conjugated substituents on the dithienogermole system were synthesized. sDPyG with highly conjugated dithienylbenzothiadiazole substituents ( 4 ) showed moderate photoluminescence (PL) behavior with quantum yields of 15–17%, regardless of the solvent (chloroform, THF, or 1,4‐dioxane). In contrast, PL quantum yields of sDPyGs with relatively less conjugated triphenylamine and phenylcarbazole substituents, respectively ( 5 and 6 ), were decreased in polar solvents without significant solvatochromic shifts of the PL bands. This seems to indicate that the photo‐induced electron transfer took place in 5 and 6 . The sDPyGs were also examined as photosensitizers for singlet oxygen ( 1 O 2 ) generation. The first‐order rate constant for the 1 O 2 generation of 6 was k obs =0.048/min, comparable to that of tetraphenylporphyrin (TPP, 0.056/min), a typical photosensitizer for 1 O 2 generation. The quantum yield of the 4 ‐sensitized 1 O 2 generation was also determined to be 0.37.