摘要:
The reaction of nickel(II) acetate with RN(O)NNHC6H4SMe (HL1: R = Me; HL2: R = Pr(n); general abbreviation HL) in aqueous ethanol affords [NiL2] as brown crystalline solids. The X-ray structure of [NiL22] is reported. Each ligand acts in the tridentate meridional SNO fashion. The Ni(SNO)2 coordination sphere is severely distorted from octahedral geometry. The Ni-S distances, 2.519(2) and 2.549(2) angstrom, constitute the longest nickel(II)-thioether bonds reported so far. Due to low symmetry, the octahedral nu1 band of the complexes are split into components lying at ca 1400 and 1000 nm. The complexes display quasireversible cyclic voltammograms corresponding to the metal redox couple [Ni(III)L2]+/[Ni(II)L2], E1/2 approximately 0.75 V (vs S.C.E.). Coulometrically generated [Ni(III)L2]+ displays rhombic EPR spectra, the g values of the perpendicular components being larger than that of the parallel component corresponding to the (d(z)2)1 ground state.