Activation of Propane C-H and C-C Bonds by Gas-Phase Pt Atom: A Theoretical Study

作者:Li, Fang-Ming; Yang, Hua-Qing*; Ju, Ting-Yong; Li, Xiang-Yuan; Hu, Chang-Wei
来源:International Journal of Molecular Sciences, 2012, 13(7): 9278-9297.
DOI:10.3390/ijms13079278

摘要

The reaction mechanism of the gas-phase Pt atom with C3H8 has been systematically investigated on the singlet and triplet potential energy surfaces at CCSD(T)//BPW91/6-311++G(d, p), Lanl2dz level. Pt atom prefers the attack of primary over secondary C-H bonds in propane. For the Pt + C3H8 reaction, the major and minor reaction channels lead to PtC3H6 + H-2 and PtCH2 + C2H6, respectively, whereas the possibility to form products PtC2H4 + CH4 is so small that it can be neglected. The minimal energy reaction pathway for the formation of PtC3H6 + H-2, involving one spin inversion, prefers to start at the triplet state and afterward proceed along the singlet state. The optimal C-C bond cleavages are assigned to C-H bond activation as the first step, followed by cleavage of a C-C bond. The C-H insertion intermediates are kinetically favored over the C-C insertion intermediates. From C-C to C-H oxidative insertion, the lowering of activation barrier is mainly caused by the more stabilizing transition state interaction Delta E-int(not equal), which is the actual interaction energy between the deformed reactants in the transition state.