Vanadium complexes dithiolene

During the period 1965-1975 the chemistry of the 1,2-dithiolene complexes of the transition metals was the subject of considerable study.86,87,91-98 However, during this period of great activity few complexes of the early transition metals were reported aside from those of vanadium. The problem had much to do with synthetic procedures, since reaction of, say, the anhydrous metal chlorides with the dithiolene or its sodium salt did not prove successful. However, the use of metal dialkylamides99 did result in clean reactions (e.g. equation 21). 

Dithiolene complexes was the name suggested by McCleverty47 for complexes of unsaturated 1,2-dithiols without implying any particular ligand structure or valence formalism. The dithiolene complexes described differ from the vanadium(III) dithiolates (Section 33.4.6) reported by three independent groups.48... 

The charge at the vanadium in the usual dithiolene complexes may be estimated49 as less than 2, and these complexes are therefore included in the section on low valence states. Various tris(dithiolene) complexes have been isolated and one-electron oxireductions studied by polarographic and voltammetric techniques. Table 3 summarizes methods of preparation and electrochemical behaviour. Schrauzer and co-workers50 correlated electrochemical data with Taft s constants the observed linear correlation reflected the ligand n orbital origin of the orbitals involved in the redox process. 

Figure 4 Electronic configurations of vanadium tris(l, 2-dithiolene) complexes (from ref. 54, based on the scheme in...

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