caa a22 4500 605510954 CHVBK 20210128100648.0 cr unu---uuuuu 210128e20150601xx s 000 0 eng 10.1007/s00894-015-2687-0 doi (NATIONALLICENCE)springer-10.1007/s00894-015-2687-0 Study of the competitive mechanisms of cyclohexane dehydrogenation by gas-phase Ni2 + cationic dimer: one-face dehydrogenation versus flip dehydrogenation [Elektronische Daten] [Jun Ma, Rong Li, Xi-long Ma, Kai-li Zhu, Zhi-yuan Geng] The mechanism of cyclohexane dehydrogenation catalyzed by the cationic dimer Ni2 + has been investigated at the B3LYP level of density functional theory. The first dehydrogenation occurs readily (it is exothermic by 30kcal/mol), whereas the second and third dehydrogenations show weaker exothermicity than the first (23 and 21kcal/mol, respectively). These three hydrogenations corresponding to the total dehydrogenation of one face of cyclohexane mainly proceed in the doublet state due to the presence of significant minimum-energy crossing points (MECPs). In addition, because the elimination of non-negligible amounts of [H2,2D2] and [2H2,D2] in this reaction was also observed in a previous experiment, we calculated a flip mechanism which would yield results that agree with those experimental results. This flip process includes two MECPs, meaning that the reaction mainly proceeds along the doublet potential energy surface but finishes in the quartet state. The rate-limiting step (2IM9 → 2TS9/10 → 2IM10) of the flip process is endothermic by 3kcal/mol and the barrier to this step is 33kcal/mol. Our calculations indicate that one-face dehydrogenation is a more favorable channel than the flip one. We excluded the possibility that eliminations of [H2,2D2] or [D2,2H2] could proceed through a mechanism involving Ni2 + dissociation, or that [H-D] scrambling could occur through 2TS11/13 (4TS12/15), due to the large amounts of energy required. In the dissociation of 2IM19, 2[(H2)Ni2(C6H6)]+, a molecule of hydrogen first dissociates, leaving a final product of 2[Ni2(C6H6)]+. Neither C6H6 nor (H2)Ni2 + can easily dissociate from 2IM19 due to π backdonation. Springer-Verlag Berlin Heidelberg, 2015 Mechanism nationallicence Exothermic nationallicence Density functional theory (DFT) nationallicence Minimum-energy crossing points (MECPs) nationallicence Ma Jun Gansu Key Laboratory of Polymer Materials, College of Chemistry and Chemical Engineering, Key Laboratory of Eco-environment-related Polymer Materials; Ministry of Education, Northwest Normal University, 730070, Lanzhou, Gansu, People's Republic of China aut Li Rong College of Chemistry and Life Science, Gansu Normal University for Nationalities, 747000, Hezuo, Gansu, People's Republic of China aut Ma Xi-long Gansu Key Laboratory of Polymer Materials, College of Chemistry and Chemical Engineering, Key Laboratory of Eco-environment-related Polymer Materials; Ministry of Education, Northwest Normal University, 730070, Lanzhou, Gansu, People's Republic of China aut Zhu Kai-li Gansu Key Laboratory of Polymer Materials, College of Chemistry and Chemical Engineering, Key Laboratory of Eco-environment-related Polymer Materials; Ministry of Education, Northwest Normal University, 730070, Lanzhou, Gansu, People's Republic of China aut Geng Zhi-yuan Gansu Key Laboratory of Polymer Materials, College of Chemistry and Chemical Engineering, Key Laboratory of Eco-environment-related Polymer Materials; Ministry of Education, Northwest Normal University, 730070, Lanzhou, Gansu, People's Republic of China aut Journal of Molecular Modeling Springer Berlin Heidelberg 21/6(2015-06-01), 1-15 1610-2940 21:6<1 2015 21 894 https://doi.org/10.1007/s00894-015-2687-0 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00894-015-2687-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ma Jun Gansu Key Laboratory of Polymer Materials, College of Chemistry and Chemical Engineering, Key Laboratory of Eco-environment-related Polymer Materials; Ministry of Education, Northwest Normal University, 730070, Lanzhou, Gansu, People's Republic of China aut NATIONALLICENCE 700 1- Li Rong College of Chemistry and Life Science, Gansu Normal University for Nationalities, 747000, Hezuo, Gansu, People's Republic of China aut NATIONALLICENCE 700 1- Ma Xi-long Gansu Key Laboratory of Polymer Materials, College of Chemistry and Chemical Engineering, Key Laboratory of Eco-environment-related Polymer Materials; Ministry of Education, Northwest Normal University, 730070, Lanzhou, Gansu, People's Republic of China aut NATIONALLICENCE 700 1- Zhu Kai-li Gansu Key Laboratory of Polymer Materials, College of Chemistry and Chemical Engineering, Key Laboratory of Eco-environment-related Polymer Materials; Ministry of Education, Northwest Normal University, 730070, Lanzhou, Gansu, People's Republic of China aut NATIONALLICENCE 700 1- Geng Zhi-yuan Gansu Key Laboratory of Polymer Materials, College of Chemistry and Chemical Engineering, Key Laboratory of Eco-environment-related Polymer Materials; Ministry of Education, Northwest Normal University, 730070, Lanzhou, Gansu, People's Republic of China aut NATIONALLICENCE 773 0- Journal of Molecular Modeling Springer Berlin Heidelberg 21/6(2015-06-01), 1-15 1610-2940 21:6<1 2015 21 894