دانلود رایگان ترجمه مقاله سنتز فاز گاز +[Ag4H] و واسطه گری آن برای تزویج C-C در برومید آلیل (نشریه وایلی 2005)

سنتز فاز گاز +[Ag4H] و واسطه گری آن برای تزویج C-C در برومید آلیل

Gas‐Phase Synthesis of [Ag4H]+ and Its Mediation of the C-C Coupling of Allyl Bromide

The formation of carbon–carbon bonds mediated by metal surfaces and nanoparticles continues to attract considerable attention.[1, 2] Recent work on the interaction of allyl halides (C3H5X) with a range of metal surfaces revealed different reactivity that depends on both the metal as well as the halide.[3, 4] Of all the metal surfaces examined, silver surfaces appear to be the most effective at mediating carbon–carbon bond coupling of allyl halides to give 1,5-hexadiene. Two distinct pathways have been observed:[4a] 1) dissociative adsorption of C3H5X to give surface-bound allyl groups, which then undergo coupling, and 2) a coupling reaction between C3H5X and a surface-bound allyl group. Surface defects play a significant role in the selectivity of 1,5- hexadiene formation which increases from 20% to greater than 60% when chlorine atoms are preadsorbed on silver surfaces.[4b] Also of interest are the largely forgotten results of Tamura and Kochi,[5] who synthesized silver nanoparticles over 30 years ago and showed that they reacted with allyl bromide to give 1,5-hexadiene and silver bromide [Eq. (1)]. Here we describe the gas-phase assembly of the subvalent silver hydride cluster [Ag4H]+[6] and its subsequent ion– molecule reactions with allyl bromide.