Ligand sulfur donor

Driven in part by interest in potential materials applications,the number of i-block complexes containing ligands with sulfur donors has increased tremendously since the 1980s. The structures of hundreds of such compounds are now known, even though the first crystal structure of a lithium thiolate did not appear until 1985.  

The x-block thiolates M(SR) are generally synthesized by one of three routes hydrogen elimination from a metal hydride (used for Na and K, Equation (5a)) alkane elimination from an alkyllithium (Equation (5b)) and metallation (used for Na-Cs, Equation (5c)). 

The reaction of [tris(3-p-tolylpyrazolyl)hydroborate)]MgMe with H2S produces the monomeric hydrosulfido complex [tris(3-p-tolylpyrazolyl)hydroborate)]MgSH, which has been structurally authenticated the Mg—S bond length is 2.35 A.Other monodentate sulfur ligands include 2-(l-methylethyl)-l,3-dimethyl-l,3,2-diazaphosphorinane 2-sulfide, whose lithium complex has been modeled with molecular orbital calculations, l,3-dimethyl-2-benzylide- 2-thioxo-1,3,2-diazaphosphorinane-S,S), and A-diisopropoxythiophosporylthiobenzamine.  

Thiocarbamates and dithiocarbonates, which have attracted interest as possible sources of metal sulfides, are known with a variety of x-block metals, including lithium, calcium,  

Reaction of 2-mercapto-l-methylimidazole and 2-mercapto-l-mesitylimidazole with LiBH4 in toluene produces the corresponding lithiated derivatives. The bidentate coordination of the sulfur atoms to lithium is augmented by donation from one of the B—H groups of the imidazole ligands. In the mesityl derivative, Li—B = 2.80, 3.09 A (values for two independent molecules)  

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Titanium triiodide can be made by direct combination of the elements or by reducing the tetraiodide with aluminum at 280°C in a sealed tube. Til reacts with nitrogen, oxygen, and sulfur donor ligands to give the corresponding adducts (148). 

Thioformamide, thiocyanate, thiophosphate, and other sulfur donor ligands 1197... 

Substitution of the coordinated aqua ligand trans to the oxo in complexes of the form [Rev0(H20)(SR)4]3+ with sulfur donor ligands (mainly thiourea type) in the equatorial cis plane, denoted by ReO(H2Q)SR. 

Fig, 1 provides a listing of the various sulfur donor ligands whose complexes have been the subject of considerable research. The list of ligands in Fig. 1 is not exhaustive since only potentially bidentate ligands are given. The electronic properties of complexes with bidentate sulfur donor ligands are usually similar although their physical properties, e.g., solubility, can vary widely. This review deals primarily with dithio- and diselenophosphate complexes however, related complexes are discussed wherever they are pertinent to the present discussion. 

Fig. 1, Examples of sulfur donor ligands. The selenium and mixed selenium-sulfur analogs of few of these ligands have been investigated...

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