Organic Photochemistry. 107. Photochemical Activation of Distal Functional Groups in Polyfunctional Molecules. Photochemistry and Photophysics of the syn-7- and anti-7-Chlorobenzonorbornenes
Organic Photochemistry. 107. Photochemical Activation of Distal Functional Groups in Polyfunctional Molecules. Photochemistry and Photophysics of the syn-7- and anti-7-Chlorobenzonorbornenes
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有机光化学。
DOI：
10.1021/ja00122a025
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发表时间：
1995
影响因子：
15
通讯作者：
H. Morrison
中科院分区：
文献类型：
--
作者：
A. J. Post;John J Nash;D. Love;K. Jordan;H. Morrison
报道了反-7-氯苯并诺贝烯(BAntiCl)和辛基-7-氯苯并诺贝烯(BSynCl)的光谱(电子吸收、荧光和电子传递)和光化学性质。这些都得到从头算分子轨道计算的补充。BSynCl异构体的LUMO含有相对较少的C-Cla*特征，在甲醇(<；3>；dis(BSynCl)=0.0014)中光解(2 54 Nm)时相对不反应。计算出BAntiCl的LUMO包含大量的C-Cl*特征，这与该异构体更大的反应活性(<；$>；dis(BantiCl)=0.23)是一致的。电子发射光谱表明，这些化合物及其exo-2-和enáo-2-氯苯甲苯异构体(分别为BExoCl和BEndoCl)相对于苯并诺贝烯(BNB)具有较强的稳定性。自然键轨道(NBO)分析表明，这种稳定作用很大程度上来自诱导效应，BAntiCl和BExoCl的*和C-Cl*轨道之间分别有相当大的穿透空间(TS)(0.07和0.10 eV)和穿透键(TB)(0.03和0.06 eV)耦合。
The spectroscopic (electronic absorption, fluorescence, and electron transmission (ET)) and photochemical properties of anti-7-chlorobenzonorbomene (BAntiCl) and syn-7-chlorobenzonorbomene (BSynCl) are reported. These are complemented by ab initio MO calculations. The BSynCl isomer, the LUMO of which contains relatively little C—Cl a* character, is relatively unreactive upon photolysis (254 nm) in methanol (< 3> diS (BSynCl)= 0.0014). The LUMO of BAntiCl is calculated to contain a significant amount of C—Cl* character, consistent with the much greater reactivity (< $> diS (BAntiCl)= 0.23) of this isomer. The ET spectra reveal that the* levels of these compounds and of their exo-2-and enáo-2-chlorobenzonorbomene isomers (BExoCl and BEndoCl, respectively) are appreciably stabilized relative to that of benzonorbomene (BNB). A natural bond orbital (NBO) analysis shows that much of this stabilization derives from inductive effects, with sizable through-space (TS)(0.07 and 0.10 eV) and throughbond (TB)(0.03 and 0.06 eV) coupling between the* and C—Cl* orbitals for BAntiCl and BExoCl, respectively.