Sulfido complexes, transition metal

This chapter is divided into two main parts. The first part focuses on reactions where the dithiolene ligand is generated independently of the metal center. For the most part, these preparations give alkenedithiolate dianions, which ordinarily are treated with metal electrophiles to form dithiolene complexes. In the second part, transition metals actively participate in the assembly of the dithiolenes, usually via the reaction of a metal sulfido species with an alkyne or hydrocarbon in an equivalent oxidation state. 

The coordination chemistry of the sulfido ligand is very varied. Scheme 4 illustrates the modes of coordination of to transition metal ions. The monosulfido ligand can act as a two-electron, terminal or /u-2-bridging donor, or up to a six-electron donor if it binds as /u.4-bridging or interstitial donor. It is, therefore, not surprising that a wide variety of binuclear and polynuclear sulfido clusters complexes can be prepared. 

Thiolato and S-based ligands have often been also used to bridge two metals with the formation of heterobimetallic complexes. The synthesis and reactivity of cubane-type sulfido clusters containing titanium-late transition metals have been reviewed.1776,1777... 

Tetrahedral sulfido or thiolate complexes are known for a number of transition metal ions including Preparative procedures involve the reaction of solutions of oxyanions with... 

Rapid desulfurization of thiiranes hy heterodinuclear complexes is achieved by using an early-late dinuclear transition-metal complex. Cp2Zr(/r-N Bu)IrCp reacts with thiiranes in almost diffusion controlled rates to give /r-sulfido complex and corresponding olefin with retention of configuration at the alkenyl carbon center (Scheme 3.68) [132]. Two mechaiusms such as completely concerted sulfur transfer reaction and insertion of the C-S bond into the Zr-Ir bond followed by concerted four-center ehmination are proposed. 

In the ground state, the oxygen atom possesses two unpaired electrons (l-4a). It is therefore a ligand of X2 type, which can bind to a transition metal to form an 0x0 complex. The sulfido (S) and imido (N-R) (l-4a) ligands behave similarly. Atomic nitrogen, with three unpaired electrons, is an X3 ligand (l-4b), giving nitrido complexes. In each case, one therefore considers all the unpaired electrons on the atom bound to the metal. 

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