Elucidate the confinement effects on transition state in nanoreaction fields using quantum-chemical model

2019 Fiscal Year Final Research Report

• Project/Area Number: 17KT0097
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 特設分野
• Research Field: Transition State Control
• Research Institution: Kyoto University
• Principal Investigator: Fukuda Ryoichi 京都大学, 実験と理論計算科学のインタープレイによる触媒・電池の元素戦略研究拠点ユニット, 特定准教授 (40397592)
• Project Period (FY): 2017-07-18 – 2020-03-31
• Keywords: 計算化学

Outline of Final Research Achievements

Chemical reaction pathways may be controlled by confining the system in tight space. To elucidate the reaction pathway, including transition states, we need to perform quantum chemical calculations. In this study, we developed the method of quantum chemical calculations for considering the confinement effect by confining the quantum chemical system in a small cavity. This method was applied to elucidate the reaction pathway, including transition states. We studied the mechanism of pericyclization reactions and isomerization reactions. The confinement effect gave stress to the reactant or suppressed the volume change in the transition state. Consequently, the overall reaction could be controlled by such confinement effects. Based on these findings, we proposed the new control factors, such as microscopic volume and pressure, for the chemical reaction mechanisms. Additionally, the proposed strategy may be extended for studying the mechanochemical methodologies.

Free Research Field

計算化学

Academic Significance and Societal Importance of the Research Achievements

熱力学的パラメータのうち温度や粒子数は、量子化学計算に比較的素直に取り込むことができ、反応自由エネルギーに対する温度やアンサンブルの効果は広く検討されている。一方で、体積や圧力は巨視的な量で、基本的に単分子を扱う量子化学計算で、体積や圧力をあらわに考慮する事は自明ではない。本研究では、単分子の量子化学計算に体積や圧力の概念を取り入れ、さらに化学反応のエネルギーを議論する方法を提案することで、ミクロな視点での反応制御に、体積や圧力という新たな制御因子を加える事ができた。また、本研究の成果は、機械的エネルギーによる化学制御であるメカノケミカル法とも関連しており、さらなる展開が期待できる。