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Photoinduced Electron Transfer of N-[(3- and 4-Diarylamino)phenyl]-1,8-Naphthalimide Dyads:  Orbital-Orthogonal Approach in a Short-linked D−A System

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journal contribution
posted on 27.03.2008, 00:00 by Seiichiro Takahashi, Koichi Nozaki, Masatoshi Kozaki, Shuichi Suzuki, Kazutoshi Keyaki, Akio Ichimura, Toshio Matsushita, Keiji Okada
The photoinduced electron transfer of a series of meta- and para-linked triphenylamine−naphthalimide dyads, N-{3- and 4-[bis(4-R-substituted phenyl)amino]phenyl}-1,8-naphthalimide, 1m,p (R = H), 2m,p (R = Me), 3m,p (R = OMe), and 4m,p (R = NMe2) was investigated in toluene and DMF. The singlet charge-transfer (CT) states were observed in all cases. The decay rates were found to be faster in DMF (τ = 6.5 ps to 100 ps) than those in toluene (τ = 190 ps to 7 ns). The long-lived triplet CT states were observed in toluene for 3 (ca. 10% contribution, τ = 670 ns for 3m, 240 ns for 3p). No long-lived species were detected in DMF. The decay rates were somewhat faster in the para-isomers than in the meta-isomers in most cases. The photolysis of 5 (p-phenylene extended analogue of 3, R = OMe) gave a singlet CT state and a locally excited triplet state on the naphthalimide chromophore.