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Magnetochemical Control of Photoreactions by Multiple Isotope Substitutions

多种同位素取代对光反应的磁化学控制

基本信息

批准号：
08640641
负责人：
NAKAGAWA Ryoichi
金额：
$ 1.47万
依托单位：
KANAZAWA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

We have investigated photochemical behavior of bichromophoric chain species containing hydrogen-donor and acceptor moieties. This type of chain molecules undergo intramolecular hydrogen abstraction reactions. Apparent magnetic field and magnetic isotope effects have been observed on photoredox reaction yields of a 4-nitro-1-naphthoxy derivative containing anilino moiety. This is one of few cases where the unimolecular cage reaction predominates in the zero-field and the bimolecular escape process becomes a major reaction pathway on application of external magnetic fields. On the other hand, conspicuous magnetic isotope effects (MIEs) have been detected on lifetimes of biradicals derived from bifunctional chain molecules consisting of aromatic carbonyl compounds and hydrogen-donor groups.Some aspects of bifunctional photochemistry of nitroaryloxy and aromatic carbonyl species are summarized as follows : [1] magnetic field effects on photoredox product yields derived from the bichromophoric parent compounds containing nitro-aromatic moieties,[2] magnetic field and magnetic isotope effects on decay profiles of biradical species,[3] disappearance of heavy carbon magnetic isotope effects in a very high field region.The third phenomenon is explained by taking account of the anisotropic magnetic interactions which contribute to the spin-lattice relaxation. The MIEs are observed when the anisotropic hyperfine interaction is of dominant importance. The MIEs disappear in the presence of very high fields (> 6T) where the anisotropic Zeeman interaction predominates.

我们研究了含氢给体和受体基团的双色素链物种的光化学行为。这类链状分子会发生分子内的氢提取反应。观察到表观磁场和磁性同位素效应对含苯胺基的4-硝基-1-萘氧基衍生物的光氧化还原反应的产率。这是零场中单分子笼形反应占主导地位的少数情况之一，而双分子逃逸过程成为外加磁场的主要反应途径之一。另一方面，由芳香族化合物和供氢基团组成的双官能性链分子衍生的双自由基的寿命受到显著的磁性同位素效应(Mies)的影响。本文总结了芳香族和硝氧基双官能团双功能光化学的几个方面：[1]磁场对含硝基-芳香族基团的双色母体光氧化还原产物产率的影响，[2]磁场和磁同位素对生物自由基物种衰变的影响，[3]重碳磁性同位素效应在高场区的消失。第三，通过考虑导致自旋-晶格弛豫的各向异性磁相互作用来解释这一现象。当各向异性超精细相互作用占主导地位时，观察到了Mie。在各向异性塞曼相互作用占主导地位的高场(~gt；6T)作用下，Mie消失。