取等比例的[PPN][Ni(CO)(2-S-C4H3S)3]和P(C6H3-3-SiMe3-2-SH)3在THF溶液中反應，可形成[PPN][NiII(2-S-C4H3S)P((C6H3-3-SiMe3-2-S)2(C6H3-3-SiMe3-2- SH))] (1)，而取等比例的NiCl2(PPh3)2和P(C6H3-3-SiMe3-2-SH)3在THF溶液中反應，則可得到[NiII(PPh3)P((C6H3-3-SiMe3-2-S)2(C6H3-3-SiMe3-2-SH))] (3)。這兩個NiII化合物為四配位，扭曲平面四邊形結構。其中，pendant thiol與Ni和Ni上的S原子會產生分子內交互作用力。經由X-ray單晶繞射鑑定結構和光譜分析，證實化合物1具有[Ni…H-S](1a)/ [Ni-S…H-S](1b)分子內的交互作用力，而化合物3的分子內作用力則屬於[Ni…H-S]交互作用力。
化合物1、3 通入O2後，會分別形成[PPN][NiIII(2-S-C4H3S)P((C6H3-3-SiMe3- 2-S)3)] (2)和[NiIII(PPh3)(P((C6H3-3-SiMe3-2-S)3)] (4)，皆為五配位，扭曲雙三角錐結構。化合物2在CH2Cl2溶液時，CH2Cl2會行dechlorination反應，化合物2會轉換成[PPN][NiIII(Cl)P((C6H3-3-SiMe3-2-S)3)]。在CO的環境下，化合物2會行reductive elimination，產生[PPN][NiII(CO)P((C6H3-3-SiMe3-2-S)3)]。而因為化合物4的terminal ligand是PPh3，是中性且是一個供給電子能力較弱的ligand，使其在CH2Cl2溶液中無法轉變成[PPN][NiIII(Cl)P((C6H3-3-SiMe3-2-S)3)]，且在CO的環境下也無法行reductive elimination，產生[PPN][NiII(CO)P((C6H3-3-SiMe3-2- S)3)]。利用環電位儀(Cyclic Voltammetry)測化合物2、4的NiIII/II氧化還原電位分別為-1.16 V、-0.83 V (vs Cp2Fe/Cp2Fe+)，皆為可逆的反應。對於這幾個化合物的幾何結構、光譜特性與反應機制可以對鎳鐵-氫化酵素做有意義的解釋。

The reaction of [PPN][Ni(CO)(2-S-C4H3S)3] with 1 equiv of P(C6H3-3-SiMe3-2- SH)3 in THF leads to form the four-coordinated complex, [PPN][NiII(2-S-C4H3S)P- ((C6H3-3-SiMe3-2-S)2(C6H3-3-SiMe3-2-SH))] (1). In the same preparation way, the reaction of NiCl2(PPh3)2 with 1 equiv of P(C6H3-3-SiMe3-2-SH)3 in THF leads to yield another four-coordinated complex, [NiII(PPh3)P((C6H3-3-SiMe3-2-S)2(C6H3-3- SiMe3-2-SH))] (3). Complexes 1 and 3 display a similar structural geometry, distorted square planar with a S-H proton interacting with both nickel center and sulfur atom. The presence of intramolecular [Ni…H-S]/[Ni-S…H-S] interactions in complexes 1 and 3 were verified in the solid state by the observation of the lower IR vS－H band and further confirmed by X-ray study. Oxidation of complexes 1 and 3 by O2 results in the formation of a mononuclear, distorted triganol bipyramidal [PPN][NiIII(2-S-C4H3S)- P((C6H3-3-SiMe3-2-S)3)] (2) and [NiIII(PPh3)(P((C6H3-3-SiMe3-2-S)3)] (4), respectively. Complex 2 undergoes dechlorination of CH2Cl2 solution to generate [PPN][NiIII(Cl)P((C6H3-3-SiMe3-2-S)3)]. In addition, complex 2 reacts with exogenous CO to produce [PPN][NiII(CO)P((C6H3-3-SiMe3-2-S)3)]. In contrast to complex 2, complex 4 is inert in the presence of CH2Cl2 and CO. This results imply that PPh3 is a weaker donating ligand than thiolate ligand (2-S-C4H3S). This result is further confirmed by the result of the cyclic voltammograms of complex 2 and 4. Complexes 2 and 4 display a reversible NiIII/II redox processes with E1/2 = -1.16 V, -0.83 V (vs Cp2Fe/ Cp2Fe+), respectively. The structure, activity, and spectroscopic properties of these complexes may show some insight about the nickel site in bimetallic Ni-Fe active site of [NiFe] Hydrogenase.

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