a 西北师范大学 化学化工学院 甘肃省高分子材料重点实验室 生态环境相关高分子材料教育部重点实验室 甘肃兰州 730070;
b 甘肃民族师范学院 化学与生命科学系 甘肃合作 747000
Mechanism and Spin-orbit Coupling Study for Two State Reaction Ni2+ with Cyclohexane
Ma Juna, Li Rongb, Ren Kuiweia, Ma Xilonga, Zhu Kailia, Geng Zhiyuana
a Key Laboratory of Polymer Materials of Gansu Province, Key laboratory of Eco-Environment-Related Polymer Materials of Ministry of Education, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, Gansu, China;
b Department of Chemistry and Life Science, Gansu Normal University for Nationalities, Hezuo 747000, Gansu, China
Two-state reaction mechanism of Ni2+ with c-C6H12 on the quartet and doublet potential energy surfaces has been investigated at the B3LYP level. As a result, the ground state for reactants is doublet state, for products is quartet state. A further study on different potential energy surfaces indicates that the title reaction contains four potential energy surfaces crossing in doublet and quartet state, which occurs during the first hydrogen migration step (4IM1→4TS1/2), the third hydrogen migration step (4TS15/16→4IM15) and flip step (4IM5→4TS5/6, 2TS11/12→2IM12), respectively. The first, second and third potential energy surfaces crossing are the transitions of quartet to doublet state, and the last one is doublet to quartet state. Using single-point energy calculations based on IRC of the different states to locate the approximate structure of crossing points (CPs) between potential energy surfaces, and more accurate structure of CPs, minimal energy crossing points (MECPs), have been obtained by the Crossing 2004 procedure. The spin-orbit coupling (SOC) constant was calculated to discuss the possible spin inversion processes. The values of SOC constants near the MECP1～MECP4 were calculated to be 318.01, 396.89, 268.74 and 306.67 cm-1, respectively, the large values of SOC constants indicate the transition from one potential energy surface to another proceeding smoothly and reducing the barrier of reaction in large extent. Based on the result of our calculation, the reaction contains two different channels, one face dehydrogenation and different face dehydrogenation, the first one is confirmed as the dominant channel due to the large exothermicity. Flip process, the critical factor leading to the different face dehydrogenation, has a large barrier of 33 kcal/mol in rate limiting step (2IM9→2TS9/10→2IM10) leading to a few different face dehydrogenation products. Our calculation can well explain the experiment observation.
马军, 李榕, 任馗玮, 马禧龙, 朱开礼, 耿志远. 两态反应Ni2+与c-C6H12的机理及自旋-轨道耦合研究[J]. 化学学报, 2015, 73(5): 431-440.
Ma Jun, Li Rong, Ren Kuiwei, Ma Xilong, Zhu Kaili, Geng Zhiyuan. Mechanism and Spin-orbit Coupling Study for Two State Reaction Ni2+ with Cyclohexane. Acta Chim. Sinica, 2015, 73(5): 431-440.