Transition metal polysulfido complex

Polysulfides have been prepared with many different types of cations, both monoatomic Hke alkah metal ions and polyatomic Hke ammonium or substituted ammonium or phosphonium ions. In this chapter only those salts will be discussed in detail which contain univalent main-group cations although a large number of transition metal polysulfido complexes have been prepared [7-9]. 

Keywords Sulfur Main group metal Transition metal Polysulfido complex... 

Desulhirization reactions of transition metal-polysulfido complexes have also been reported. The treatment of a dimetallic complex of titanium, [ Ti(Cp)(OAr) 2(yU-S)(yU-S2)] (Cp=77 -C5H5, Ar=2,6-i-Pr2C6H3), with an equimolar amount of PhsP results in the quantitative formation of [ Ti(Cp)(OAr) 2(yU-S)2] via the transformation of the 1U-S2 ligand to a /t-S ligand (Scheme 44) [93]. The reverse reaction of [ Ti(Cp)(OAr) 2(/t-S)2] with Ss proceeds in a good yield. 

EtsP S = PEt3 Scheme 44 Desulfurization of transition metal polysulfido complexes... 

Metal polysulfido complexes have attracted much interest not only from the viewpoint of fundamental chemistry but also because of their potential for applications. Various types of metal polysulfido complexes have been reported as shown in Fig. 1. The diversity of the structures results from the nature of sulfur atoms which can adopt a variety of coordination environments (mainly two- and three-coordination) and form catenated structures with various chain lengths. On the other hand, transition metal polysulfides have attracted interest as catalysts and intermediates in enzymatic processes and in catalytic reactions of industrial importance such as the desulfurization of oil and coal. In addition, there has been much interest in the use of metal polysulfido complexes as precursors for metal-sulfur clusters. The chemistry of metal polysulfido complexes has been studied extensively, and many reviews have been published [1-10]. 

Polysulfido Complexes of Main Group and Transition Metals... 

In this review, we describe the topics reported during the last ten years for the synthesis, structure, and reactivity of polysulfido complexes of main group and transition metals. 

A variety of polysulfido complexes of transition metals has also been synthesized by the reactions of low-valent metal complexes with elemental sulfur. 

Reactions of metal halides with polysulfide dianions are useful methods for the synthesis of polysulfido complexes of main group elements and transition metals. In most of these reactions, similarly to other methods, the chain lengths and coordination types of the polysulfide ligands depend on the other ligands coordinated to the metal, on the ratio between the metal and sulfur, on the reaction temperature, and other parameters. 

Takeda N, Tokitoh N, Okazaki R (2003) Polysulfido Complexes of Main Group and Transition Metals. 231 153-202... 

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