Tao Hong Li

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Organization: Southwest Forestry University

Department: Department of Chemistry

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Organic Chemistry

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References

CH bond activation of ethylene by bare neutral palladium and platinum atoms: a theoretical investigation

Co-reporter:Tao Hong Li;Chuan Ming Wang;Xiao Guang Xie

Journal of Physical Organic Chemistry 2011 Volume 24( Issue 4) pp:292-298

Publication Date(Web):

DOI:10.1002/poc.1748

Abstract

The reactions of bare neutral palladium (Pd) and platinum (Pt) atoms with ethylene on both singlet and triplet surfaces were investigated at B3LYP and CCSD (T) levels of theory. The calculated potential energy profiles clearly show that Pt has higher reactivity than Pd toward ethylene. For both Pd and Pt, the reactions on singlet surfaces are energetically more favorable than those on triplet surfaces. However, notable barriers lie on the singlet and triplet surfaces for Pd +ethylene. This result rationalizes the experimental observation that Pd mainly forms π-complex with ethylene. But under high-energy condition, the reaction can proceed to yield dehydrogenation products, Pd-CCH. and Pd (HCCH). For Pt, triplet-singlet surface crossing was suggested to occur in the region where Pt forms π-complex with ethylene to lead the reactions to the energetically more favorable singlet surfaces. For both the two metals, π-complex and CH bond insertion species are the reaction intermediates and the H.-elimination products are the final products. Copyright © 2010 John Wiley & Sons, Ltd.

A DFT study on the mechanisms for gas phase reaction of yttrium with propene

Co-reporter:Tao Hong Li;Xiao Guang Xie

Journal of Physical Organic Chemistry 2010 Volume 23( Issue 8) pp:768-775

Publication Date(Web):

DOI:10.1002/poc.1655

Abstract

The gas phase reaction of ground-state yttrium (Y) with propene, previously examined by crossed molecular beams (CMBs) experiment, has been theoretically investigated in detail using B3LYP method. Three concerted and five stepwise pathways were found for H₂ elimination. The calculated PESs indicate that the concerted mechanisms are energetically much more favorable than the stepwise mechanisms for the elimination of H₂. Three isomers, Y-propyne, Y-allene, and Y(CHCHCH₂), were assigned to the experimentally observed H₂-elimination product, YC₃H₄. Three pathways were identified for the CC bond cleavage products, YCH₂ + C₂H₄. The energetically most favorable pathway involves the formation of a metallacyclobutane intermediate, which can decay to YCH₂ + C₂H₄. The results of this study confirmed some previous inferences and provided more details for the title reaction. Copyright © 2010 John Wiley & Sons, Ltd.

Mechanisms for H2 and CH3 elimination in the gas phase reaction of propyne with Zr: A DFT study

Co-reporter:Tao Hong Li, Chuan Ming Wang, Shi Wen Yu, Xiang Yi Liu, Hui Fu, Xiao Guang Xie

Chemical Physics Letters 2009 Volume 475(1–3) pp:34-39

Publication Date(Web):16 June 2009

DOI:10.1016/j.cplett.2009.05.014

The reaction of ground-state Zr with propyne has been investigated using B3LYP method. Four H2 elimination pathways were identified. Three isomers, Zr(HCCCH), Zr(CCCH2) and Zr–CCCH2 were identified for the experimentally observed product ZrC3H2. For elimination of CH3, besides the previously proposed direct sp–sp3 C–C bond insertion mechanism, a novel C–C bond activation mechanism was also elucidated. The two different CH3 elimination mechanisms also lead to two isomers (Zr–CCH and Zr(CC)H) for the product ZrC2H. Our calculations found that the formation of Zr–CCH and Zr(CC)H is highly endothermic by 88.3 and 83.5 kJ/mol, respectively, at B3LYP/TZVP + RECP level, which rationalizes the absence of the products (ZrC2H + CH3) in experiment.The elimination of CH3 involves the initial methyl C–H bond activation, followed by insertion of Zr into CC bond.

A theoretical study on the gas phase reaction of Au+ with CH3F

Co-reporter:Tao Hong Li, Chuan Ming Wang, Shi Wen Yu, Xiang Yi Liu, Xiang Hong Li, Xiao Guang Xie

Chemical Physics Letters 2008 Volume 463(4–6) pp:334-339

Publication Date(Web):1 October 2008

DOI:10.1016/j.cplett.2008.08.073

Abstract

The reaction of CH₃F with Au⁺ has been investigated at B3LYP and CCSD(T) levels. It was found that both C–F and C–H bonds can be activated by ground state Au⁺(¹S), whereas only C–H bond activation pathway was identified for excited state Au⁺(³D). Among the possible product channels, the formation of ${AuCH}_{2}^{+}$ corresponding to HF-elimination is most favorable. Three reaction pathways were identified for HF-elimination. The energetically most favorable one undergoes through a mechanism of C–H bond activation → C–F bond activation → HF elimination. The activation barrier of this pathway is calculated to be small as 5.4 kJ/mol. The results of this study well rationalize the experimental observations.

DFT study on the gas phase reaction of Ni+ with CS2

Co-reporter:Tao Hong Li, Chuan Ming Wang, Xiang Yi Liu, Xiao Guang Xie

Chemical Physics Letters 2008 Volume 458(1–3) pp:19-23

Publication Date(Web):6 June 2008

DOI:10.1016/j.cplett.2008.04.057

The reaction of Ni+ with CS2 has been investigated at B3LYP/TZVP and B3LYP/6-311 + G∗ levels of theory. The reaction mechanisms have been explored in detail on both doublet and quartet potential energy surfaces. The products observed in the experiment have been explained according to the cleavage of different bonds in the insertion intermediate S–Ni+–C–S. The product [Ni, C, S]+ observed in experiment was confirmed as Ni–CS+ (2Σ). The spin-forbidden reaction Ni+(2D) + CS2 → NiS+(4Σ) + CS (1Σ) was found to proceed through a doublet–quartet surface crossing and the crossing seam was approximately calculated.The spin-forbidden reaction Ni+(2D) + CS2 → NiS+(4Σ) + CS (1Σ) was found to proceed through a doublet–quartet surface crossing.