The competition between allene and butadiene in the carbon-hydrogen bond activation initiated by a tungsten allyl complex: A DFT study
Academic Article
Overview
Research
Identity
Additional Document Info
Other
View All
Overview
abstract
Mechanisms for H-transfer from 1,1-dimethylallyl (DMA) to neopentyl (CH 2t-Bu) in the complex Cp*W(NO)(CH 2t-Bu) ( 3-DMA) are examined by B3LYP-DFT calculations. Either the mid-H or the methyl H on the DMA can transfer to the W-bound neopentyl to generate neopentane (2,2-dimethylpropane) and Cp*W(NO)( 2-1,1- dimethylallene) or Cp*W(NO)( 2-2-methylbuta-1,3-diene) intermediates, respectively. The open coordination site created by the neopentane loss is the site of the subsequent C-H bond activation of alkanes and arenes. The similarities in the overall enthalpic barriers for these mechanisms, 23-24 kcal/mol, explain the observed deuterium distribution (65% on the mid-carbon and 35% on the methyls of the DMA) when benzene-d 6 reacts as substrate. 2005 American Chemical Society.
