Analyzes and Designs of Local Electronic Structures of Molecules and Chemical Reactions

本研究的目的是通过实验化学家和理论家之间的讨论和密切合作，使理论更加完善和进一步发展，以发现通用化学的新原理。到目前为止所取得的结果总结如下。1.通过对Hartree-Fock分子轨道理论进行修正，考察了pi电子能量的物理意义和可加性。2.应用微扰理论，阐明了环戊二烯的最高占位分子轨道的形变。从轨道形状的角度讨论了环加成反应的表面选择性。3.研究了β-取代碘盐的溶解机理。4.应用密度泛函理论研究了正方形平面铂(II)及其相关络合物的重排途径。除了能量和结构计算外，应用Walsh图计算轨道相互作用表明，一些适当选择的配体将提供迄今尚未发现的稳定的四面体铂(II)和钯(II)配合物。5.以SP^3C-H键的还原消除和活化为例，证明了从头算方法在揭示化学反应的分子机理方面是非常有用的。6.合成了含五甲基环戊二烯配体的钼、钨硫络合物，并从电子能量的角度研究了它们的簇合物及其稳定性。7.具有扭曲pi电子体系的八氢-4，4‘-联苯亚甲基得到光学活性对映体。由理论计算确定的这些对映体的立体化学已被实验研究证明是正确的。

The purpose of this research is to make the theories more sophisticated and develop further to find out new principles in chemistry of general use through discussions and intimate cooperation between experimental chemists and theoreticians. The results so far obtained are summarized as follows. 1. By introducing a modification into the Hartree-Fock MO theory, the physical significance and the additivity of the pi electronic energy have been examined. 2. By applying the perturbation theory, the deformation of the highest occupied MO of cyclopentadiene has been clarified. The facial selectivity in cycloaddition has been discussed in terms of the shape of the orbital. 3. The mechanism of solvolysis in beta-substituted iodonium salts has been investigated. 4. The paths for the rearrangement of the square planar platinum (II) and related complexes have been studied by applying the density functional theory. In addition to the energy and structure calculations, orbital interactions by applying the Walsh diagram have indicated that some ligands chosen appropriately will provide stable tetrahedral Pt (II) and Pd (II) complexes that have not been found so far. 5. By taking reductive eliminations and activations of sp^3 C-H bonds as examples, ab initio Mo calculations have been demonstrated to be very useful in disclosing the molecular mechanisms of chemical reactions. 6. Sulfur complexes of molybdenum and tungsten having pentamethylcyclopentadienyl ligands have been synthesized and their clusters and stabilities have been studied from an electronic energy viewpoint. 7. Octahydro-4,4'-biphenanthrylidenes having twisted pi electron systems give optically active enantiomers. The stereochemistry of those enantiomers determined by theoretical calculations have been proved to be correct by experimental studies.