Magnetochemical Control of Photoreactions by Multiple Isotope Substitutions

我们研究了含氢供体和受体的双色链物种的光化学行为。这种链式分子发生分子内吸氢反应。研究了含苯胺基的4-硝基-1-萘氧基衍生物光氧化还原反应产率的磁场效应和磁同位素效应。这是在零场条件下单分子笼反应占主导地位，外加磁场作用下双分子逃逸过程成为主要反应途径的少数情况之一。另一方面，由芳香羰基化合物和给氢基团组成的双官能链分子衍生出的双自由基的寿命受到明显的磁同位素效应（MIEs）的影响。本文综述了硝基羰基和芳香羰基双功能光化学的一些方面：[1]磁场对含硝基芳香基团的双色亲本化合物的光氧化还原产物产率的影响；[2]磁场和磁同位素对双基物质衰变谱的影响；[3]重碳磁同位素效应在甚高场区的消失。第三种现象是通过考虑各向异性磁相互作用来解释的，这有助于自旋晶格弛豫。当各向异性超细相互作用占主导地位时，可以观察到微观结构。在各向异性塞曼相互作用占主导地位的极高场（bbbb6t）存在时，密斯消失。

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.