- Anchoring Triazole-Gold(I) Complex into Porous Organic Polymer to Boost the Stability and Reactivity of Gold(I) Catalyst
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Stability and reactivity have been recognized as some critical issues for gold(I) catalysts. Such issues can be well-circumvented by anchoring the gold(I) complex onto the backbones of porous organic polymer (POP) followed by coordination with a triazole ligand as illustrated in the present work via a series of gold(I)-catalyzed reactions. In this strategy, 1,2,3-triazole was used as the special "X-factor" to avoid the formation of solid AgCl involved in typical gold-activation processes. The catalyst could be readily recycled without loss of reactivity. Moreover, compared with the PPh3-modified polystyrene beads, the POP support was advantageous by providing high surface area, hierarchical porosity, and better stabilization of cations. In some cases, significantly improved reactivity was observed, even more so than using the homogeneous system, which further highlighted the great potential of this heterogeneous gold catalyst.
- Cai, Rong,Ye, Xiaohan,Sun, Qi,He, Qiuqin,He, Ying,Ma, Shengqian,Shi, Xiaodong
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p. 1087 - 1092
(2017/08/09)
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- "Silver effect" in gold(I) catalysis: An overlooked important factor
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Clear experimental evidence from X-ray photoelectron spectroscopy and 31P NMR spectroscopy has been obtained for the first time to confirm that the combination of Ag+ cation with [L-Au]+ results in the formation of different complexes in solution. Re-evaluation of literature-reported gold-catalyzed reactions revealed a significant difference in the reactivities with and without silver. In extreme cases (more than "rare"), the conventional [L-Au]+ catalysts could not promote the reaction without the presence of silver. This investigation has therefore revealed a long-overlooked "silver effect" in gold catalysis and should lead to revision of the actual mechanism.
- Wang, Dawei,Cai, Rong,Sharma, Sripadh,Jirak, James,Thummanapelli, Sravan K.,Akhmedov, Novruz G.,Zhang, Hui,Liu, Xingbo,Petersen, Jeffrey L.,Shi, Xiaodong
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scheme or table
p. 9012 - 9019
(2012/07/02)
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- The Influence of Intramolecular Dynamics on Branching Ratios in Thermal Rearrangements
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1- and 2-phenylbicyclohex-2-enes-5-d undergo thermal rearrangement to give products, differing only in the location of the deuterium, in ratio of about 9:1, but with identical activation enthalphies.Similarly, opticallly active trans-2-methyl-1-(trans-2-phenylethenyl)cyclopropane is found to rearrange to enantiomeric methylphenylcyclopentenes that are formed in a 5.9:1 ratio but with virtually identicyl activation enthalphies.Barring repeated coincidence, these results do not seem to be explicable within the framework of statistical theories of unimolecular kinetics such as RRKM theory, transition state theory, and variational transition state theory.The possible influence of dynamic effects in these and other unimolecular reactions is discussed.
- Newmann-Evans, Richard H.,Simon, Reyna J.,Carpenter, B. K.
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p. 695 - 711
(2007/10/02)
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