Theoretical Study on the Reaction Mechanism of VO2+ with Propyne in Gas Phase
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- 作者：Lourdes Gracia ; Victor Polo ; Julio R. Sambrano ; Juan André ; s
- 刊名：Journal of Physical Chemistry A
- 出版年：2008
- 出版时间：February 28, 2008
- 年：2008
- 卷：112
- 期：8
- 页码：1808 - 1816
- 全文大小：581K
- 年卷期：v.112,no.8(February 28, 2008)
- ISSN：1520-5215
文摘
Possible molecular mechanisms of the gas-phase ion/molecule reaction of VO2+ in its lowest singlet andtriplet states (1A1/3A' ') with propyne have been investigated theoretically by density functional theory (DFT)methods. The geometries, energetic values, and bonding features of all stationary and intersystem crossingpoints involved in the five different reaction pathways (paths 1-5), in both high-spin (triplet) and low-spin(singlet) surfaces, are reported and analyzed. The oxidation reaction starts by a hydrogen transfer from propynemolecule to the vanadyl complex, followed by oxygen migration to the hydrocarbon moiety. A hydride transferprocess to the vanadium atom opens four different reaction courses, paths 1-4, while path 5 arises from ahydrogen transfer process to the hydroxyl group. Five crossing points between high- and low-spin states arefound: one of them takes place before the first branching point, while the others occur along path 1. Fourdifferent exit channels are found: elimination of hydrogen molecule to yield propynaldehyde and VO+ (1
/3); formation of propynaldehyde and the moiety V-(OH2)+; and two elimination processes of water moleculeto yield cationic products, Prod-fc+ and Prod-dc+ where the vanadium atom adopts a four- and di-coordinatestructure, respectively.
/3); formation of propynaldehyde and the moiety V-(OH2)+; and two elimination processes of water moleculeto yield cationic products, Prod-fc+ and Prod-dc+ where the vanadium atom adopts a four- and di-coordinatestructure, respectively.