The chemical and electronic structure of the neutral flavin radical as revealed by electron spin resonance spectroscopy of chemically and isotopically substituted derivatives.
The chemical and electronic structure of the neutral flavin radical as revealed by electron spin resonance spectroscopy of chemically and isotopically substituted derivatives.
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通过化学和同位素取代衍生物的电子自旋共振光谱揭示中性黄素自由基的化学和电子结构。
DOI：
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发表时间：
1970
期刊：
影响因子：
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通讯作者：
V. Massey
中科院分区：
文献类型：
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作者：
F. Müller;P. Hemmerich;A. Ehrenberg;G. Palmer;V. Massey
用电子能谱法对中性黄醌半醌进行了详细的研究。进行了同位素（15N，2H）和化学取代。本文描述了中性黄酰半醌的超精细偶联方案，其中涉及N（5），N（10），CH_3（10），CH_3（8）和H（6）。最高的自旋密度位于N（5）处，这也已经在阴离子和螯合形式的黄酮半醌中发现。中性黄半醌中的可交换质子连接到N（5）上，其耦合常数为7.6 G，与N（5）的耦合常数大致相同。超精细耦合的自旋密度和比较的解释与可用的量子化学计算。有证据表明，两种互变异构形式的中性flavosemiquinone被认为是可以得到一个纯的形式通过适当的取代的黄素衍生物。这两种中性的黄酰半醌很容易通过它们的电子自旋共振和光散射来区分。
The neutral flavosemiquinone has been studied in detail by electron spectroscopy. Isotopic (15N, 2H) and chemical substitutions have been carried out. A hyperfine coupling scheme of the neutral flavosemiquinone is described where N(5), N(10), CH3(10), CH3(8) and H(6) are involved. The highest spin density is located at N(5) as has also been found for the anionic and chelated form of the flavosemiquinone. The exchangeable proton in the neutral flavosemiquinone is attached to N(5) having a coupling constant of 7.6 G which is about the same magnitude as the coupling constant to N(5). The hyperfine couplings are interpreted in terms of spin densities and comparison is made with available quantum chemical calculations. Evidence is presented that two tautomeric forms of the neutral flavosemiquinone have to be considered which can be obtained in a pure form by suitable substitution of flavin derivatives. The two types of neutral flavosemiquinones are easily distinguishable by their electron spin resonance and light absorptions.