Theoretical study of homo-coupling reaction of different hybridization
state at the α-carbon: ethyl(-CH2CH3) and methylacetylide(-C≡CCH3)
coupling on Ag(111) surface
Jyh-Shing Lin and Shao-Yu Lu
Department of Chemistry, Tamkung University
Tel:02-2621-5656#2813; E-mail: 897160031@s97.tku.edu.tw
Born-Oppenheimer molecular dynamic (BOMD) simulations in connection with
the Fourier transform of the dipole moment autocorrelation function (FT-DMAF) was
used to investigate the effect of hybridization state of Cα on the coupling reaction of
ethyl(-CH2CH3)(ads) and methylacetylide(-C≡CCH3)(ads) on Ag(111) surface, namely
Csp3-Csp3 , Csp-Csp homo-coupling. Molecular dynamic simulations have established
the diffusion dynamic of adsobred ethyl and acetylide on Ag(111) surface. Based on
these dynamic results, we proposed the most favorable reaction pathways for these
two coupling reactions. Our calculated energy barrier (1.34eV) for the coupling of
(-C≡CCH3)(ads) coadsorbed on Ag(111) surface is 0.64eV higher than (-CH2CH3)(ads).
According to Redhead approximation, we found that temperatures for both coupling
reactions of ethyl(-CH2CH3)(ads) and methylacetylide(-C≡CCH3)(ads) due to different
hybridization state at Cα are 210K and 510K, respectively. These results are
qualitatively in good agreement with the experimental observations [1,2].
Reference:
1.
H. Kung, S.-M. Wu, Y.-J. Wu, Y.-W. Yang, and C.-M. Chiang. J. Am. Chem. Soc. 2008, 130, 10263.
2.
A. Paul, A. J. Gellman. J. Am. Chem. Soc. 1995, 117, 9056.