Magnesium thiolates

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... 

The chemistry of alkaline-earth chacogenolates have been developed from the nineties with the structural characterization of the first magnesium thiolate in 1990,69 magnesium and calcium tellurolates in 1992,70,71 and the first magnesium and strontium selenolates in 1994.72... 

Janssen, Maurits D., Grove, David M., and Koten, Gerard van, Copper(I) Lithium and Magnesium Thiolate Complexes An Overview with Due Mention of Selenolate and Tellurolate Analogues and Related SilverfI) and Gold(I)... 

Benzyne generated from 2-iodophenyl 4-chlorobenzenesulfonate by treatment with tropropyl magnesium chloride at low temperature adds to the magnesium thiolate derived from thiosalicylic acid 530 to form thioxanthone. The carboxyl function behaves as an electrophile towards the intermediate aryl magnesium species and an intramolecular cyclization ensues (Scheme 212) <2005AGE4258>. 

The overall outcome of this reaction looks somewhat puzzling, but the reaction course, which includes successive alkylation with the Grignard reagent and elimination of magnesium thiolate, was proposed as in Scheme 3 [228]. The first oxidative addition of Ni° species to the Csp -S bond was promoted through coordination by an additional intramolecular oxygen or sulfur functional group. 

Within this overview of copper(I), lithium, and magnesium thiolate complexes, one of the aims is to highlight the influence that (intramolecular) nitrogen coordination exerts on the structure of such species, since intermolecular (auxiliary) coordination of heteroatoms often leads to poorly defined species. An example of this poor species definition is the reaction behavior of polymeric copper(I) thiophenolate, [Cu(SPh)]. with triphenylphosphine Several P-coordinated aggregates with variable stoichiometry were reported (Scheme 1) (27-29). This behavior makes it difficult to study one specific species in cop-per(I) thiolate catalyzed organic reactions since equilibria are likely to occur. 

III. LITHIUM AND MAGNESIUM THIOLATE COMPLEXES A. Lithium and Magnesium Thiolates in Perspective... 

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. 

The preparation of lithium and magnesium thiolates commonly comprises the reaction of a suitable lithium or magnesium base with the corresponding thiol at low temperature (Eq, 11). 

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