2005 Fiscal Year Final Research Report Summary
Theoretical Study of Flexible Molecular Systems Possessing Complexed Electronic Structure Towards Reaction Design and Control
| Project/Area Number |
15350012
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Physical chemistry
|
|---|
| Research Institution | Kyoto University |
|---|
Principal Investigator |
SAKAKI Shigeyoshi Kyoto University, Graduate School of Engineering, Professor, 工学研究科, 教授 (20094013)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SATO Hirofumi Kyoto University, Graduate School of Engineering, Associate Professor, 工学研究科, 助教授 (70290905)
NAKAO Yoshihide Kyoto University, Graduate School of Engineering, Research Associate, 工学研究科, 助手 (40362462)
|
|---|
| Project Period (FY) |
2003 – 2005
|
| Keywords | Electronic Structure Theory / Transition Metal Complexes / Reaction Mechanism / Bonding Nature / Structure / Electron correlation effects / Reaction control / Function control |
|---|
| Research Abstract |
Theoretical Studies with electronic structure theory were carried out about hydrosilylation of alkene, hydrogenation of carbon dioxide, and Stille coupling reaction, which are typical transition-metal-catalyzed reaction. The hydrosilylation of alkene by Cp_2Zr takes place not only through alkene insertion into Zr-H bond but also coupling reaction between Zr-alkene species and hydrosilane. The product release step is not simple C-H and Si-C reductive elimination but alkene-assisted reductive eliminations and metathesis with hydrosilane. These differences from the late-transition-metal catalyzed hydrosilylation arise from the d orbital energy difference. Reaction mechanism of Ru-catalyzed hydrogenation of carbon dioxide was also theoretically elucidated in the presence of water molecule ; not the insertion of carbon dioxide into Ru-H but nucleophilic attack of hydride to carbon center of CO_2 takes place in the presence of water molecule, of which activation barrier is much smaller than usual CO_2 insertion. Stille coupling reaction takes place through oxidative addition of iodobenzene, transmetallation, and reductive elimination. Transmetallation is rate-determining step, which is accelerated by the presence of fluoride anion. The reason was discussed on the basis of bond energy.
|
