Abstract
Addition of complex [PPN][NiIII(OPh)(P(C6H3-3-SiMe3-2-S)3)] into the THF-EtOH mixed solution of [Me4N][OH] yielded complex [PPN][NiIII(OEt)(P(C6H3- 3-SiMe3-2-S)3)] (1). Complex [PPN][NiIII(OCH2Ph)(P(C6H3-3-SiMe3-2-S)3)] (2) was synthesized by using [Me4N][OH] in PhCH2OH instead of EtOH. Complexes 1 and 2, characterized by single-crystal X-ray diffraction, SQUID, EPR and UV-Vis, were mononuclear Ni(III) complexes. The geometry of the Ni center is a five-coordinate distorted trigonal bipyramidal. Complexes 1 or 2 reacted with 4,4,5,5-tetramethyl-1,3,2-dioxaborolane in 1:1 molar ratio in THF, respectively, yielded complex [PPN][NiIII(H)(P(C6H3-3-SiMe3-2- S)3)] (3) at 213 K. Complex 3 was thermally unstable at 213 K and was chactraterized by EPR and UV-Vis spectroscopy. The byproduct of the reaction could be detected by 1H NMR and GC-MS. Addition of CS2 into the THF solution of complex 3 underwent the insertion reaction to form complex [PPN][NiIII(SC(S)H)(P(C6H3-3-SiMe3-2-S)3)]. Also, reaction of CO2 and complex 3 led to the formation of complex [PPN][Ni(P(C6H3-3-SiMe3-2-S)3)]2. The byproduct [OC(O)H]- anion could be detected by 1H NMR. The insertion of CS2 and CO2 into complex 3 demonstrated that the Ni(III)-hydride was synthesized. To my best knowledge, complex 3 is the first Ni(III)-hydride complex. Moreover, CO2 bubbled into the THF solution of complex 1 or 2 yielded complex [PPN][NiIII(OCO)(P(C6H3-3-SiMe3-2-S)3)], as we expected by using [PPN][NiIII(OMe)(P(C6H3-3-SiMe3-2-S)3)] reacted with CO2 in the previous studies. The reaction mechanism was also proposed.