A comparative photophysical and photochemical study of nitropyrene isomers occurring in the environment.
A comparative photophysical and photochemical study of nitropyrene isomers occurring in the environment.
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DOI：
10.1021/jp108652p
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发表时间：
2011-01-20
影响因子：
2.9
通讯作者：
Morel, Maria
中科院分区：
文献类型：
--
作者：
Arce, Rafael;Pino, Eduardo F.;Valle, Carlos;Negron-Encarnacion, Ideliz;Morel, Maria
在不同的条件下，可以模拟环境中遇到的大气气溶胶中的单硝基芘异构体的基态吸收，第一激发单重态，和活性中间体的性质进行了研究。硝基可以根据其几何位置相对于芘环呈现不同的取向，并且可以引起异构体的光化学差异。2-NO2 Py异构体在与硝基相关的紫外-可见波段具有最大的红移和最低的振子强度。异构体显示出非常低的荧光产率（10−3-10−4）。只有1-NO2 Py和4-NO2 Py具有磷光发射（Φp ≈ 10 - 4），表明最低三重态主要通过有效的无辐射通道衰变。激光光解产生一个低位三重态（τT = 10−5-10−6 s），一个长寿命的芘氧自由基，和一个PyNO 2 H自由基，在溶剂中三重态可以夺取一个氢原子。相似的三重产率计算（0.1-0.6）的异构体，而显着差异的相对产量的长寿命的物种被确定。水和酚类的三重态的淬灭速率常数的差异表明在C-2位与硝基的强氢键相互作用，这提供了无辐射失活途径。
Ground state absorption, first excited-singlet state, and properties of reactive intermediates of mononitropyrene isomers encountered in the atmospheric aerosol have been studied under different conditions that could mimic the environment. The nitro group can present different orientation relative to the pyrene ring depending on its geometric location and could induce differences in the photochemistry of the isomers. The 2-NO2Py isomer has the largest red shift and lowest oscillator strength in the UV-visible band associated with the nitrogroup. The isomers show very low fluorescence yields (10−3–10−4). Only 1-NO2Py and 4-NO2Py have phosphorescence emission (Φp ≈ 10−4), indicating that the lowest triplet state decays mainly through effective radiationless channels. Laser photolysis produces a low lying triplet state (τT = 10−5–10−6 s), a long-lived pyrenoxy radical, and a PyNO2H radical in solvents in which the triplet can abstract a hydrogen atom. Similar triplet yields were calculated (0.1–0.6) for the isomers while significant differences in the relative yield of the long-lived species were determined. Differences in the quenching rate constants of the triplet by water and phenols suggest a strong hydrogen bond interaction with the nitro group in the C-2 position, which provides for radiationless deactivation routes.
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影响因子：
11.4
作者：
Feilberg, A;Nielsen, T
通讯作者：
Nielsen, T
DOI：
10.1039/b202889c
发表时间：
2002-01-01
期刊：
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2
影响因子：
--
作者：
Görner, H
通讯作者：
Görner, H
DOI：
10.1016/0047-2670(82)80003-8
发表时间：
1982-01-01
期刊：
JOURNAL OF PHOTOCHEMISTRY
影响因子：
--
作者：
GUSTEN, H;HEINRICH, G
通讯作者：
HEINRICH, G
影响因子：
15
作者：
Leigh, WJ;Lathioor, EC;StPierre, MJ
通讯作者：
StPierre, MJ
影响因子：
2.8
作者：
JUNG, HW;SHAIKH, AU;FU, PP
通讯作者：
FU, PP