Quantum-Chemical Study of “Hydride” Mobility in the Molecules of Chalcogenopyrans
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- 作者：A. N. Pankratov and B. I. Drevko
- 关键词：chalcogenopyrans ; “ ; hydride” ; transfer ; quantum ; chemical investigation ; reaction mechanisms ; ionization potential ; hydrogen atom affinity ; hydride ion affinity ; proton affinity
- 刊名：Chemistry of Heterocyclic Compounds
- 出版时间：September 2005
- 出版年：2005
- 期刊代码：19_00093122
- 类别：mat
- 卷：41
- 期：9
- 页码：1105-1111
- 数据来源：sp
摘要
An approach is proposed for the quantum-chemical investigation of “hydride ion” transfer based on analysis of the similarity of the order of variation in the ionization potentials, enthalpies, and free energies of affinity to the hydride ion, the hydrogen atom, and the proton in the substrate molecules and also the derivatives of their cations, radicals, and ions to the experimentally established “hydride” series. It was established that the experimental “hydride” mobility series of six chalcogenopyrans based on “semicyclic” 1,5-diketones agrees with the quantum-chemically calculated ionization potentials of the molecules and with the affinity of the respective radicals to the hydrogen atom participating in the transfer. It was found that direct removal of a hydride ion and initial deprotonation of the substrates followed by the removal of two electrons are unlikely. “Hydride” shift mechanisms, in which the first stage is transfer of an electron or hydrogen atom from the chalcogenopyran molecules, are feasible.