title: Cobalt(iii) complexes bearing bidentate, tridentate, and tetradentate N-heterocyclic carbenes: synthesis, X-ray structures and catalytic activities.
abstract: Cobalt(iii) complexes, [CoCl(2)(L1)(2)](PF(6)) (1, L1 = N-methyl-N-(2-pyrimidinyl)imidazolylidene), [CoCl(L2)(2)](PF(6))(2) (, L2 = N-picolyl-(2-pyrimidinyl)imidazolylidene), [Co(L3)(2)](PF(6))(3) (3, L3 = bis(N-2-pyrimidylimidazolylidenyl)methane) and [CoCl(2)(L3)](PF(6)) (4) have been prepared from the corresponding pyrimidine functionalized imidazolium salts [HL1](PF(6)), [HL2](PF(6)), and [H(2)L3](PF(6))(2)via in situ generated silver carbene complexes under mild conditions. These cobalt complexes were characterized by (1)H and (13)C NMR spectroscopy and X-ray diffraction analysis. The cobalt complexes have been found to be good catalyst precursors for Kumada-Corriu cross-coupling reactions of aryl halides and Grignard reagents at room temperature. Complex 1 is more active under the mild conditions.
authors.affiliation: Department of Chemistry, Zhejiang University, Xixi Campus, Hangzhou, 310028, People's Republic of China.
authors.forename: Zhenxing
authors.initials: Z
authors.lastname: Xi
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.forename: Chunxin
authors.initials: C
authors.lastname: Lu
authors.forename: Wanzhi
authors.initials: W
authors.lastname: Chen
mesh_terms: D003035:Cobalt / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006571:Heterocyclic Compounds / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C030011:carbene; D003035:Cobalt; D008697:Methane