Abstract
The previously synthesized P(C6H3-3-SiMe3-2-S)3 can serve as a ligand to produce a series of nickel(III) complexes.Here we synthesize P(C6H4-2-N(CH3)2)3, expected to produce Ni(I) complex, and study its effect on the activation of small molecules. The NiII(ClO4)2 • 6H2O reacting with P(C6H4-2-N(CH3)2)3 (1:1 molar ratio) in MeCN at room temperature under dinitrogen atmosphere yielded complex [NiII(NCMe)2(OH2)(P(C6H4-2-N(CH3)2)3)] [ClO4]2 (1). Complex 1, characterized by single-crystal X-ray diffraction, SQUID, EPR, 1H NMR, IR and UV-Vis, was demonstrated to be mononuclear high-spin Ni(II) complex, containing two unpaired electrons. The geometry of the Ni center is a six-coordinate distorted octahedral complex. In addition, Ni powder and [NO][BF4] were reacted to synthesize [Ni(NCMe)6][BF4]2. Reaction of [Ni(NCMe)6][BF4]2 with an equal proportion of P(C6H4-2-N(CH3)2)3 yielded complex [NiII(NCMe)2(OH2)(P(C6H4-2-N(CH3)2)3)][BF4]2 (2). Complexes 1 or 2 reacting with the equivalent of KC8 at low temperatures under dinitrogen atmosphere, respectively, yielded complex [NiI(NCMe)2(P(C6H4-2-N(CH3)2)3)][X] (X = ClO4or BF4) (3). Complex 3 was sensitive to dioxygen and was characterized by UV-Vis and EPR spectroscopy. In the activation of small molecules, compound 3 may react with CS2 or CO2, to yield [NiIII(η2-CS2)(P(C6H4-2-N(CH3)2)3)] or [NiIII(η2-CO2)(P(C6H4-2-N(CH3)2)3)], characterized by UV-Vis and EPR. The [NiIII(η2-CS2)(P(C6H4-2-N(CH3)2)3)] reacting with KC8 in 1:1 molar ratio at low temperatures under dinitrogen atmosphere produced [NiII(η2-CS2)(P(C6H4-2-N(CH3)2)3)] (4). Complex 4, characterized by X-ray, UV-Vis, IR, 1H NMR, was low-spin Ni(II) complex.The geometry of the Ni center is a four-coordinate distorted square-planar complex.