کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9605468 | 44101 | 2005 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Solvent effects on the quenching of the equilibrating n,Ï* and Ï,Ï* triplet states of 9,10-phenanthrenequinone by 2-propanol
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
بیو مهندسی (مهندسی زیستی)
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Quenching of the triplet state of 9,10-phenanthrenequinone (PQ) by 2-propanol was studied using laser flash photolysis. The room temperature rate constant is solvent dependent and is 3.3(±1.1) Ã 108 Mâ1 sâ1 in carbon tetrachloride (CCl4), 1.2(±0.3) Ã 108 Mâ1 sâ1 in chlorobenzene (CB), and 2.5(±0.8) Ã 107 Mâ1 sâ1 in acetonitrile (MeCN). The rate constant in CCl4 is the largest known for abstraction of hydrogen from 2-propanol by an excited ketone. An activation energy of 0.017(±0.006) kcal/mol and a pre-exponential A factor of the Arrhenius equation of 4.45 Ã 108 Mâ1 sâ1 was found in CCl4; an activation energy of 2.14(±0.006) kcal/mol and an A factor of 4.5 Ã 108 was found in MeCN. These results are consistent with a mechanism involving a reactive n,Ï* triplet in thermal equilibrium with a non-reactive Ï,Ï* triplet, and are in agreement with a previous study of the room temperature phosphorescence of PQ showing that the lowest energy triplet is n,Ï* in CCl4 but Ï,Ï* in MeCN.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 175, Issues 2â3, 31 October 2005, Pages 154-158
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 175, Issues 2â3, 31 October 2005, Pages 154-158
نویسندگان
David E. Nicodem, Rosaly S. Silva, Denisio M. Togashi, Maria Fernanda V. da Cunha,