DFT study of the reactions of Mo and Mo⁺ with CO₂ in gas phase

DEMAN HAN, GUOLIANG DAI*, HAO CHEN, HUA YAN, JUNYONG WU, CHUANFENG WANG and AIGUO ZHONG

School of Pharmaceutical and Chemical Engineering, Taizhou University, Linhai 317000, People’s Republic of China

*Corresponding author. E-mail: daigl@tzc.edu.cn

MS received 8 April 2010; revised 6 September 2010; accepted 4 February 2011

Abstract. Density functional theory (DFT) calculations have been performed to explore the potential energy surfaces of C–O bond activation in CO₂ molecule by gas-phase Mo⁺ cation and Mo atom, in order to better understanding the mechanism of second-row metal reacting with CO₂. The minimum energy reaction path is found to involve the spin inversion in the different reaction steps. This potential energy curve-crossing dramatically affects reaction exothermic. The present results show that the reaction mechanism is insertion-elimination mechanism along the C–O bond activation branch. All the theoretical results not only support the existing conclusions inferred from early experiment, but also complement the pathway and mechanism for this reaction.

Graphical Abstract. For the reaction between Mo atom and CO₂, it is found that the reaction system would likely to change its spin multiplicity twice in going from the entrance channel to the exit channel. Specifically, it can be described as ⁵Mo+CO₂→⁵IM1→⁵TS₁₂→⁵IM2→⁵TS₂₃→CP4→³IM3→CP6→⁵MoO+CO.

Keywords. Density functional theory; potential energy surface; transition-metal; reaction mechanism.