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Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents
Published on: May 28, 2014
Cyclotrimerization of alkynes catalyzed by a self-supported cyclic tri-nuclear nickel(0) complex with α-diimine
Lingyi Shen1, Yanxia Zhao, Qiong Luo
1Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069, China. yangxiaojuan@nwu.edu.cn.
Abstract:
A cyclic tri-nuclear α-diimine nickel(0) complex [{Ni(μ-LMe-2,4)}3] (2) was synthesized from a "pre-organized", trimerized trigonal LNiBr2-type precursor [Ni3(μ2-Br)3(μ3-Br)2(LMe-2,4)3]·Br (1; LMe-2,4 = [(2,4-Me2C6H3)NC(Me)]2). In complex 2, the α-diimine ligands not only exhibit the normal N,N'-chelating mode, but they also act as bridges between the Ni atoms through an unusual π-coordination of a C[double bond, length as m-dash]N bond to Ni. Complex 2 is able to catalyze the cyclotrimerization of alkynes to form substituted benzenes in good yield and regio-selectivity for the 1,3,5-isomers, which is found to vary with the nature of the alkyne employed. This complex represents a convenient self-supported nickel(0) catalyst with no need for additional ligands and reducing agent.
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