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NCUEIR > College of Science > Department of Chemistry > Periodical Articles > Item 987654321/15157

Please use this identifier to cite or link to this item: http://ir.ncue.edu.tw/ir/handle/987654321/15157

Title:	Effects of the Counteranion on the Pyrazole-Nitrile Coupling Reaction Mediated by Nickel(II) Ions
Authors:	Hsieh, Chang-Chih;Lee, Chia-Jung;Horng, Yih-Chern
Contributors:	化學系
Date:	2009-09
Issue Date:	2013-01-07T02:15:58Z
Publisher:	American Chemical Society
Abstract:	The reaction of Ni(ClO4)2 with 4 equiv of pyrazole (pzH) in MeCN leads to [Ni(pzH)2(HNd C(Me)pz)2](ClO4)2 via the intermediate [Ni(MeCN)2(pzH)4](ClO4)2, which is the first pyrazole-nitrile coupling reaction activated by a Ni(II) complex. The reaction is also successfully conducted with other nitriles RCN bearing an electron-donating group (R=Et, Bz) and is counteranion-specific. The reaction proceedsmore quickly withNO3 -as counteranion than withClO4 -, andBF4 -is found to be unsatisfactory for the coupling reaction. As for the X-ray crystal structures, [Ni(MeCN)2(pzH)4](ClO4)2 possesses stronger pyrazolyl NH3 3 3 anion hydrogen-bonding interactions than does [Ni(MeCN)2(pzH)4](BF4)2. The same trend is also observed by solution IR(pyrazolylNH) analysis. The supramolecular structure of the complex [Ni(pzH)2(HNdC(Me)pz)2](ClO4)2 displays a two-dimensional network dominated by cooperative face-toface π-π stacking and edge-to-face CH3 3 3 π bonding interactions. In addition, a mechanism based on anion-mediated/hydrogen-bonding-driven proton transfer for the coupling reaction is proposed.
Relation:	Organometallics, 28(17): 4923-4928
Appears in Collections:	[Department of Chemistry] Periodical Articles

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