Preparation and Properties of Monoalkylnickel(II) Complexes NiR(NR1R2)L2 Having Imido, Imidazolato, or Methyl Phenylcarbamato-N Ligand

Article abstract of DOI:10.1246/bcsj.54.1720

Reactions of dialkylnickel(II) complexes NiR2L2 1 (R=CH3, C2H5; L=1/2 bpy(2,2'-bipyridine), 1/2 dpe(1,2-bis(diphenylphosphino)ethane), PEt3) with compounds having acidic N-H bonds (succinimide, phthalimide, diacetamide, pyromellitimide (1,2 : 4,5-benzenebis(dicarboximide)), imidazole) gave corresponding monoalkylnickel(II) complexes having Ni-N bond formulated as NiR(NR¹R²)L2.A reaction of NiMe2(PEt3)2 with CH3OH and phenyl isocyanate gives NiMe(N(Ph)COOMe)(PEt3)2.The IR, NMR, and visible spectroscopic studies of the complexes indicate that the electronegativity of Ni is enhanced by the replacement of one of the two R groups in 1 with the NR¹R² ligand.NMR spectra of complexes of a type NiMe(NR¹R²)(PEt3)2 show that they have trans-configurations.Thermolyses of the monoalkylnickel(II) complexes start at temperatures higher by 80-100 deg C than those of 1, liberating RH, R-R, and olefin R(-H).Exposure of monoethylnickel(II) complexes to air releases ethylene as the main gaseous product.Reactions of the complexes of a type NiR(phthalimido)L2 with R'X (R'=C6H5, C6H5CH2) and C6H5COCl produce N-alkyl- or N-arylphthalimide and ketone C6H5COR, respectively.