Heterobimetallic complexes containing an N-heterocyclic carbene based multidentate ligand and catalyzed tandem click/Sonogashira reactions
作者:Shaojin Gu、Daichao Xu、Wanzhi Chen
DOI:10.1039/c0dt01211d
日期:——
Mono- and polynuclear complexes containing 3-(1,10-phenanthrolin-2-yl)-1-(pyridin-2-ylmethyl)imidazolylidene (L), [NiL2](PF6)2 (2), [CoL2](PF6)3 (3), [PtLCl](PF6) (4), [PdAgL2](PF6)3 (5), [PdCuL2](PF6)3 (6), [Pd2L2Cl2](PF6)2 (7), and [Pd3L2Cl4](PF6)2 (8) have been prepared and fully characterized by NMR, ESI-MS spectroscopy, and X-ray crystallography. In complexes 2–4, the ligand binds to metals in a pincer NNC fashion with the pyridine group uncoordinated. Complexes 5 and 6 are isostructural to each other in which the palladium ions are surrounded by two pyridines and two imidazolylidenes and Ag(I) or Cu(I) is coordinated by two 1,10-phenanthroline moieties. In the trinuclear palladium complex 8, one palladium ion has an identical coordination mode as in 5 and 6, and the other two palladium ions are bonded to the 1,10-phenanthroline. Complex 6 exhibits excellent catalytic activity for the tandem click/Sonogashira reaction of 1-(bromomethyl)-4-iodobenzene, NaN3, and ethynylbenzene in which three C–N bonds and one C–C bond are formed in a single flask.
单核和多核配合物含有3-(1,10-菲咯啉-2-基)-1-(吡啶-2-甲基)咪唑烷基(L),[NiL2](PF6)2(2),[CoL2](PF6)3(3),[PtLCl](PF6)(4),[PdAgL2](PF6)3(5),[PdCuL2](PF6)3(6),[Pd2L2Cl2](PF6)2(7),和[Pd3L2Cl4](PF6)2(8)已经被制备并通过NMR、ESI-MS光谱和X射线晶体学进行了全面表征。在配合物2-4中,配体以夹钳式NNC方式与金属结合,吡啶基团未参与配位。配合物5和6在结构上相互等同,其中钯离子被两个吡啶和两个咪唑烷基包围,Ag(I)或Cu(I)通过两个1,10-菲咯啉部分配位。在三核钯配合物8中,一个钯离子具有与5和6相同的配位模式,其他两个钯离子与1,10-菲咯啉结合。配合物6显示出优异的催化活性,对于1-(溴甲基)-4-碘苯、NaN3和乙炔苯的串联点击/Sonogashira反应,其中在单一反应瓶中形成三个C–N键和一个C–C键。