Transition Metal Thiometalates: Properties and Significance in Complex and Bioinorganic Chemistry

In their highest oxidation states the early transition metals V, Nb, Ta, Mo, W, and Re form tetrahedral, strongly colored thioanions endowed with some remarkable properties. Thiometalates can be formed by solid-state reactions or in solution from the oxometalates. Poly-thiometalates with mixed valences can be produced by new types of intramolecular condensation-redox reactions from thioanions. The metal-sulfur bonds can react either nucleophilically or electrophilically, and in the case of the Mo–S bonds this is of biochemical interest. It is important to mention the applications of thiometalates as ligands in complex chemistry (generation of multi-metal complexes, versatile coordination behavior, unique electronic properties of the ligands), in which thiometalato complexes with a variety of electron populations can exist because of the marked electron delocalization. Apart from this, MoS has a significance in bioinorganic problems, e.g. the nitrogenase problem and Cu? Mo antagonism.