Addition of Unactivated Alkynes to Metal Sulfides

The inorganic clusters [Mo3(p3-S)(p2-E)(p2-S)2(H20)9]4+ (E = O, S) add acetylene at room temperature in aqueous 1 M HC1 solution to give the dithiolene (243). The dithiolene ligand adopts an unusual bonding mode, wherein each thiolate sulfur atom bridges two metals (Fig. 19). The cluster 

The anion [ReS4], which is isoelectronic with the well-known d°-oxo-transfer agents [Mn04] and 0s04, binds a variety of unactivated alkynes (Fig. 20). 

The CpCo/Rh promoted reaction with sulfur and alkynes is the basis of a catalytic synthesis of thiophenes (258). 

From Metal Sulfides and a-IIaloketones and Related Precursors 

This method has found particular use in the preparation of pyridine-substituted dithiolene complexes, which exhibit pH sensitive luminescence properties (263). The a-halocarbonyl starting materials could include related precursors used in the synthesis of unsaturated dithiocarbonates described in Section II.C. 

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