ALIPHATIC KETONE ANION-RADICALS : A MATRIX ISOLATION ESR STUDY
ALIPHATIC KETONE ANION-RADICALS : A MATRIX ISOLATION ESR STUDY
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脂肪族酮阴离子自由基：基质分离 ESR 研究
DOI：
10.1021/j100100a016
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
P. H. Kasai
中科院分区：
文献类型：
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作者：
R. Koeppe;P. H. Kasai
脂肪酮阴离子(酮基自由基)是在~4K温度下，在弱辐射(=590 nm)的作用下，与Ar基质中的Na原子共缩合，产生电子转移的产物。对丙酮、二乙酮、二异丙基酮、异丁基甲基酮和环丁酮的阴离子自由基的ESR谱进行了观察和分析。用从头算(UHF)和半经验(AMI)分子轨道计算对丙酮阴离子进行了计算，得到了(甲基)的结构和构象，与观测到的~(？)质子和C-13超精细耦合张量的结果一致.结果表明，这些阴离子具有R2C-CT(70%)*·R2C_-(30%)形式的半占据分子轨道(SOMO)，在碳端呈锥形。在~4K下的Ar矩阵中，在给定的反转到未成对电子轨道的位置处锁定了？烷基
Aliphatic ketone anions (ketyl radicals) were produced by cocondensing aliphatic ketones and Na atoms in argon matrices at~ 4 K and effecting electron transfer between them by mild radiation (= 590 nm). ESR spectra of anion radicals of acetone, diethyl ketone, diisopropyl ketone, ieri-butyl methyl ketone, and cyclobutanone were thus observed and analyzed. Examination of the acetone anion by ab initio SCF (UHF) and semiemperical (AMI) molecular orbital calculations yielded the structure and the conformation (of the methyl groups) in reasonable agreement with those deduced from the observed ß proton and a C-13 hyperfine coupling tensors. It is concluded that these anions have a semioccupied molecular orbital (SOMO) of the form R2C-CT (70%)*· R2C_—Ó (30%) and are pyramidal in shape at the a carbon. In argon matrices at~ 4 K, the ß alkyl groups are locked at a given trans to the unpaired electron orbital at the