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Studies on Molecular Orbital Interaction in the Heteroatom System

杂原子体系中分子轨道相互作用的研究

基本信息

批准号：
03453026
负责人：
TOMODA Shuji
金额：
$ 4.29万
依托单位：
UNIVERSITY OF TOKYO
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

The present research proposal aims at the mechanistic studies of molecular orbital interactions in organic compounds containing heteroatom(s). The following three projects have been completed or partially completed.1. Studies of a weak interaction involving group-16 elementsWe have investigated the nature of two weak interactions, i.e. hydrogen bonds involving group-16 elements and Se・・・N non-bonded attractive interaction. In general, hydrogen bonds are formed by electrostatic attractive forces between electronegative elements. However spectroscopic studies on the hydrogen bonding system X・・・H-Y(X=O, S, Se, Te and Y=O, C) have revealed that orbital interaction seems important in heavy heteroatom systems. In particular, it has been found that there exists fairly strong Se・・・H-C hydrogen bond, in which electrostatic attraction is not expected Se・・・N non-bonded attractive interaction(J.Am.Chem, Soc., 116, 1994 in press as a short communication). Se・・・N non-bonded attractive interaction ha … More s also been studied both experimental and theoretical point of view. It was found that this interaction is not an electrostatic one either(J.Am.Chem, Soc., submitted).2. Importance of orbital interaction in glutathione peroxidase catalytic cycleGlutathione peroxidase is a poly peptide enzyme which reduces hydrogen peroxide generated as a metabolite of active oxygen in animals. Its active center contains a selenium atom that is surrounded by two nitrogen atoms of amino acid residues. The plausible roles of these proximate nitrogen atoms on the catalytic cycle have been studied using a simple model compound containing a selenium and a proximate tertiary amino nitrogen. This work will appear in J.Am.Chem, Soc., 116, 1994 as a full paper.3. Studies on the selectivities of organic reactionsTwo projects have been completed. One concerns with the pi-facial stereoselectivity of hydride reduction of cyclic ketones(J.Am.Chem, Soc., submitted) and the other is the regioselectivity in the Sn2 reaction of heteroatom-substituted epoxides. In both cases, LUMO extension outside repulsive molecular surface evaluated by "Exterior Electron Density" seems to play an important role on dictation of selectivities. Less

本课题旨在研究含杂原子有机化合物分子轨道相互作用的机理。以下三个项目已经完成或部分完成。涉及16族元素的弱相互作用的研究我们研究了两种弱相互作用的性质，即涉及16族元素的氢键和Se···N非键吸引相互作用。一般来说，氢键是由电负性元素之间的静电引力形成的。然而，对氢键系统X····H-Y（X=O， S, Se， Te和Y=O， C）的光谱研究表明，轨道相互作用在重杂原子系统中似乎很重要。特别是，已经发现存在相当强的Se···H-C氢键，其中静电吸引是预料不到的Se···N非键吸引相互作用(J.Am.；化学,Soc。（1994年11月16日，作为简短通讯出版）。从实验和理论两方面研究了硒·····N的非键吸引相互作用。人们发现这种相互作用也不是静电作用。化学,Soc。,提交)。2。轨道相互作用在谷胱甘肽过氧化物酶催化循环中的重要性谷胱甘肽过氧化物酶是一种多肽酶，它可以减少动物体内活性氧代谢产物产生的过氧化氢。它的活性中心包含一个硒原子，被两个氨基酸残基的氮原子包围。这些近似的氮原子在催化循环中的合理作用已经用一个简单的模型化合物含硒和近似叔氨基氮进行了研究。这部作品将刊登在j。化学,Soc。(3)论文全文。有机反应选择性研究已完成2个项目。一个是关于环酮氢化物还原的面立体选择性（j . m.）。化学,Soc。二是杂原子取代环氧化合物Sn2反应的区域选择性。在这两种情况下，由“外电子密度”评价的LUMO在排斥分子表面外的延伸似乎对选择性的决定起着重要作用。少