Acetonitrile accessible potential range

NCS, NH3, PR, py, CNR,...) have reversible potentials ranging from -0.3 to +2.0 V in acetonitrile vs. the saturated sodium chloride calomel (SSCE) reference electrode (2) and electron transfer involving such couples is known to be facile (3). Ru(IV) is also an accessible oxidation state at relatively low potentials by loss o grotons from bound water following oxidation, Ru(bpy)2(py)... 

Figure 3.166 shows the reactivity and potential of these early transition metal pincer carbene complexes taking vanadium as an example. The broad range of compounds becomes possible owing to the rich redox chemistry of vanadium that makes different oxidation states easily accessible. Here, examples for vanadium(ll), vanadium(III) and vanadium(IV) are shown. Abstraction of halogen is facile making the introduction of different TT-donor ligands possible, even weak ones like acetonitrile. 

---