title: Nickel complexes incorporating an amido phosphine chelate with a pendant amine arm: synthesis, structure, and catalytic Kumada coupling.
abstract: A series of organonickel(II) complexes incorporating an amido phosphine ligand tethered with an amino pendant have been prepared and characterized. Deprotonation of N-(dimethylaminoethyl)-2-diphenylphosphinoaniline (H[PNN]) with one equivalent of n-BuLi in ethereal or hydrocarbon solutions at -35 °C generates cleanly dimeric {Li[PNN]}(2) as yellow crystals. The reaction of NiCl(2)(DME) with {Li[PNN]}(2) in THF at -35 °C affords green crystalline [PNN]NiCl. Treating [PNN]NiCl with NaX in acetone solutions gives [PNN]NiX (X = Br, I). Alkylation or arylation of [PNN]NiCl with appropriate Grignard reagents in THF at -35 °C produces red crystalline [PNN]NiR (R = Me, Et, i-Bu, n-hexyl, CH(2)Ph, Ph). The chloride complex [PNN]NiCl was found to be an active catalyst precursor for Kumada coupling reactions of PhX (X = I, Br, Cl) with aryl or alkyl Grignard reagents, including those containing β-hydrogen atoms. The X-ray structures of {Li[PNN]}(2) and [PNN]NiX (X = Cl, Br, Me, Et, n-hexyl) are reported.
authors: Department of Chemistry and Center for Nanoscience & Nanotechnology, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan. lcliang@mail.nsysu.edu.tw
authors: Lan-Chang
authors: LC
authors: Liang
authors: Wei-Ying
authors: WY
authors: Lee
authors: Yu-Ting
authors: YT
authors: Hung
authors: Yi-Chen
authors: YC
authors: Hsiao
authors: Liang-Chien
authors: LC
authors: Cheng
authors: Wei-Chen
authors: WC
authors: Chen