Lithium chalcogenolates

The aim of this chapter is to review the chemistry of chalcogenolates in the last 10 years. The more recent reviews in this field included chalcogenolates of the s-block elements,13,14 early transition metal thiolates,15 metal complexes with selenolate and tellurolate ligands,16 copper(I), lithium and magnesium thiolates,17 functionalized thiolate complexes,18 19 pentafluorobenzenethiolate platinum group compounds,20 tellurium derivatives,21 luminescent gold compounds,22 and complexes with lanthanide or actinide.23... 

This is a widely used preparation route towards metal chalcogenolates since the alkali compounds, mainly lithium and sodium derivatives, react with halogen complexes of almost any metal. The chalcogenols in the presence of a base can be used to scavenge the hydrogen halide. 

When the bromine-lithium exchange and chalcogenol-formation are carried out in sequence employing S, Te or Se, Te, naphtho[1,8-cr/][l, 2]chalcogcnotelluroles were obtained. The unsymmetric compounds were separated from the two symmetric compounds by column chromatography on silica gel with hexane as the mobile phase3 6. 

Neither diferrocenyl ether ( Fc-O-Fc ) nor diferrocenyl peroxide ( Fc-OO-Fc ) are known so far. However, the corresponding compounds of sulfur, selenium and tellurium are well characterized (see Sect. 5.8). The dichalcogenides Fc-EE-Fc (E = S, Se, Te) are easily obtained by oxidative dimerisation of either the lithium ferrocenyl chalcogenate, Fc-ELi, or the chalcogenols, Fc-EH, for which they can be used as stable precursors (Sect. 5.3.3) [91, 95]. Reaction of the dichalcogenides Fc-EE-Fc with Fc-Li is a possible route to the monochalcogenides, Fc-E-Fc, but the yields are... 

The synthesis generally involves reaction of either the ferrocenyl chalcogenols and l,l -ferrocenylene dichalcogenols, Fc-EH and fc(EH)2, or (preferably) the corresponding lithium derivatives, Fc-ELi and fc(ELi)2, with halides such as acid chlorides, non-metal chlorides and chloro metal complexes (E = S, Se, Te). 

Reports that thermolysis of metal chalcogenolate complexes offers a low-temperature route to the synthesis of novel solid state materials (32) is also stimulating research in this area. As is the case with copper(I) thiolates, lithium thiolates are often aggregated species (Section III.C) and from the few magnesium thiolate structures known (Section III.D) one sees a preference for monomeric and dimeric formulations when bulky substituents are present. 

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