Hexanuclear cyclometallated

Dinuclear cyclometallated complexes are usually prepared starting from the metal chloride and the cyclometallating ligand (Figure 5, top). The same type of synthesis can be used to prepare cyclometallated complexes of high nuclearity. As an example, the recently reported synthesis of a hexanuclear cyclometallated complex is shown in Figure 5, bottom. ... 

The hexanuclear cyclometallated complex 61 (Scheme 1 and Table 1) shows a single reversible oxidation process at +1.31 V (Table 2), which involves four electrons. This process can be attributed to the oxidation of the four, almost noninteracting, peripheral Ru(ll) metals. The lack of other oxidation processes is an expected result since the increase (+4) in the charge of the complex displaces the oxidation of the core outside the accessible potential window. 

The hexanuclear cyclometallated compound 61 (Scheme 1 and Table 1) shows five reduction processes (Table 2). The first one, which occurs at a potential very close to the first reduction of the model compound [(bpyljRufdppnH)], is revcrs-... 

Figure 5. (a) Metal chlorides can react with simple cyclometalating ligands to give dinuclear cyclometallated complexes, (b) Schematic representation of the synthesis of a hexanuclear complex containing cyclometallated units. ... 

---