کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5376363 1504324 2007 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Proton transfer in phenothiazine photochemical oxidation: Laser flash photolysis and fluorescence studies
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Proton transfer in phenothiazine photochemical oxidation: Laser flash photolysis and fluorescence studies
چکیده انگلیسی
Phenothiazine (PTH) cation and neutral radical have been characterized by nanosecond laser flash photolysis in basic and acid acetonitrile. In the presence of water or small amounts of base, the radical cation (PTH+) was not detected and the neutral radical (PT) was the only observed radical in photoionization process. Triplet PTH (3PTH∗) was quenched by diethyl fumarate in acetonitrile at a rapid rate (kqT=6.1×109M-1s-1), and then, it was observed a specific absorption around 410 nm that is assigned to PT formed via photoinduced electron/proton transfer. However, no PT was detected on 3PTH∗quenching by cinnamonitrile (CN). On the basis of the results, the fast proton transfer in the oxidation process is mainly dependent on the basic groups, such as the carbonyl group in electron acceptors. The quenching rate constants (kqT) of 3PTH∗ by various electron acceptors have been determined at 470 nm as well as fluorescence quenching rate constants kqS obtained by Stern-Volmer equation. All kqT and kqS values approach the diffusion limit. The driving force dependence of bimolecular quenching rate constants was evaluated in light of Rehm-Weller analysis. In addition, disharmonic kq values by CN in endergonic region might be the contribution of charge transfer.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Physics - Volume 334, Issues 1–3, 20 April 2007, Pages 224-231
نویسندگان
, , , , , , ,