Cyclotrimerization of alkynes catalyzed by a self-supported cyclic tri-nuclear nickel(0) complex with α-diimine ligands
作者:Lingyi Shen、Yanxia Zhao、Qiong Luo、Qian-Shu Li、Bin Liu、Carl Redshaw、Biao Wu、Xiao-Juan Yang
DOI:10.1039/c9dt00819e
日期:——
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 CN bond to Ni. Complex 2 is
环状三核α-二亚胺镍(0)络合物[Ni(μ- LMe -2,4)} 3 ](2)是由“预组织”的三聚LNiBr 2型三方前体[倪3(μ 2 -Br)3(μ 3 -Br)2(L ME-2,4)3 ]·能Br(1 ; l ME-2,4 = [(2,4--ME 2 ç 6 ħ 3)NC(Me)] 2)。在配合物2中,α-二亚胺配体不仅表现出正常的N,N'-螯合模式,但它们也通过C N键与Ni的不寻常π配位而充当Ni原子之间的桥梁。配合物2能够催化炔烃的环三聚反应以形成高产率和对1,3,5-异构体的区域选择性的取代苯,这随所用炔烃的性质而变化。该络合物代表一种方便的自支撑镍(0)催化剂,不需要其他配体和还原剂。