Preparation of stable alkyl complexes of Ni(I) and their one-electron oxidation to Ni(II) complex cations.
The three-coordinate nickel(I) alkyl complexes (dtbpe)Ni(CH2CMe3) (2), (dtbpe)Ni(CH2SiMe3) (3), and (dtbpe)Ni(CH2CMe2Ph) (4) have been prepared by treatment of [(dtbpe)NiCl]2 with alkyllithium reagents. While thermally robust, they each undergo mild one-electron oxidation to give the corresponding Ni(II) complex cations [(dtbpe)Ni(CH2CMe3)+] (5), [(dtbpe)Ni(CH2SiMe3)+] (6), and [(dtbpe)Ni(CH2CMe2Ph)+] (7) as red-brown [PF6-] or [BArF4-] salts. In contrast to cationic amido and phosphido analogues that undergo alpha-deprotonation to afford imido and phosphinidene derivatives, deprotonation of 5-7 occurs at a gamma-CH3 group to give metallacyclobutane products (dtbpe)Ni(CH2CMe2CH2) (8), (dtbpe)Ni(CH2SiMe2CH2) (9), and (dtbpe)Ni(CH2CPhMeCH2) (10), not (dtbpe)Ni=CHR.
Searle Chemistry Laboratory, Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA.
Kristina D
KD
Kitiachvili
Daniel J
DJ
Mindiola
Gregory L
GL
Hillhouse
D002413:Cations, Divalent / Q000737:chemistry; D002414:Cations, Monovalent / Q000737:chemistry; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction
D002413:Cations, Divalent; D002414:Cations, Monovalent; D009942:Organometallic Compounds; D009532:Nickel