کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5401661 | 1392717 | 2011 | 4 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Time-resolved studies on the photoisomerization of a phenylene-silylene-vinylene type compound in its first singlet excited state
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
In femtosecond laser-flash photolysis experiments, the first singlet excited state of trans-ST, ((E,E)-{1,4-bis(2-dimethylphenylsilyl)ethenyl}benzene) showed a strong S1(Ï,Ïâ)-Sn absorption band at 540 nm in acetonitrile and at 550 nm in hexane. The lifetime of this state was determined to be 13.2±2.0 and 11.1±1.5 ps, respectively. Intersystem crossing was shown not to be a principal route for the deactivation of this S1 state of trans-ST. Evidence for this conclusion involved two complementary nanosecond laser-flash photolysis experiments. In one experiment involving direct excitation, no transient absorption spectrum was detected in the 350-650 nm spectral range. Yet, in the second experiment, on triplet sensitization, using xanthone, a transient absorption at 400 nm was tentatively assigned to the triplet state absorption of trans-ST. Photoisomerization was monitored in nanosecond time-resolved bleaching experiments. From these experiments the trans-cis photoisomerization quantum yield was determined to be 0.23 on direct trans-ST excitation. In a xanthone-sensitized stationary-state excitation experiment, the trans-cis isomerization quantum yield was determined to be 0.32. The main deactivation route of trans-ST in its S1 state is repopulation of the ground state directly through internal conversion or with the intermediacy of conformers with twisted geometry.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Luminescence - Volume 131, Issue 4, April 2011, Pages 577-580
Journal: Journal of Luminescence - Volume 131, Issue 4, April 2011, Pages 577-580
نویسندگان
G. Burdzinski, M. Bayda, G.L. Hug, M. Majchrzak, B. Marciniec, B. Marciniak,