摘要
Mononuclear, distorted square planar [Ni II (ER)(P(o-C 6 H 4 S) 2 (o-C 6 H 4 SH))] - (ER = SePh (1), 2-S-C 4 H 3 S (2)) with a S-H proton directly interacting with both nickel and sulfur atoms were prepared by reaction of [Ni(CO)(SePh) 3 ] - /[Ni(CO)(2-S-C 4 H 3 S) 3 ] - and P(o-C 6 H 4 SH) 3 , individually. The presence of combinations of intramolecular [Ni-S⋯H-SR]/[Ni⋯H-SR] interactions was verified in the solid state by the observation of an IR ν SH stretching band (2273 and 2283 cm -1 (KBr) for complexes 1 and 2, individually) and 1 H NMR spectra (δ 8.079 (d) (CD 2 Cl 2 ) and 8.39 (d) (C 4 D 8 O) ppm (-SH) for complexes 1 and 2, respectively) and subsequently confirmed by X-ray diffraction study. The exo-thiol proton (o-C 6 H 4 SH) in complexes 1 and 2 was identified as a D 2 O exchangeable proton from NMR and IR studies and was quantitatively removed by Lewis base Et 3 N to yield Ni(II) dimer [Ni II (P(o-C 6 H 4 S) 3 )] 2 2- (5). Instead of the ligand-based oxidation to form dinuclear Ni(II) complexes and dichalcogenide, oxidation of THF-CH 3 CN solution of complexes 1 and 2 by O 2 resulted in the formation of the mononuclear, distorted trigonal bipyramidal [Ni III (ER)(P(o-C 6 H 4 S) 3 )] - (ER = SePh (3), 2-S-C 4 H 3 S (4)) accompanied by byproduct H 2 O identified by 1 H NMR, respectively. The 4.2 K EPR spectra of complexes 3 and 4 exhibiting high rhombicities with three principal gvalues of 2.304, 2.091, and 2.0 are consonant with Ni(III) with the odd electron in the d z 2 orbital. Complex 3 undergoes a reversible Ni III/II process at E 1/2 = -0.67 V vs Ag/AgCl in MeCN.