title: Dinuclear versus mononuclear pathways in zinc mediated nucleophilic addition: a combined experimental and DFT study.
abstract: Employing the oxidative coupling of phenylacetylene with benzaldehyde as a model reaction, a density functional theory (DFT) study combined with extended X-ray absorption fine structure (EXAFS) experiment was carried out to reveal the difference between dinuclear and mononuclear zinc mediated nucleophilic addition. Newly reported DFT method M11-L computed results suggest that the mononuclear zinc mediated pathway, in which nucleophilic addition occurs via a four-membered ring transition state, is unfavourable both thermodynamically and kinetically. The dinuclear zinc mechanism, which appropriately explains the experimental observations, involves a six-membered ring transition state for nucleophilic addition. Subsequent in situ EXAFS experiment confirmed the existence of dinuclear zinc active species. Moreover, frontier molecular orbital (FMO) analysis and distortion-interaction energy analysis along the whole reaction pathways have provided interpretations for the advantage of dinuclear zinc mediated nucleophilic addition. Consequently, we believe this dinuclear zinc pathway will open up a general consideration of the dinuclear zinc mechanism for nucleophilic additions.
authors.affiliation: School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, P. R. China. lanyu@cqu.edu.cn.
authors.forename: Xiaotian
authors.initials: X
authors.lastname: Qi
authors.forename: Yingzi
authors.initials: Y
authors.lastname: Li
authors.forename: Guanghui
authors.initials: G
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Aiwen
authors.initials: A
authors.lastname: Lei
authors.forename: Chao
authors.initials: C
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Lan