SYNTHESIS, CHEMICAL-REACTIONS AND REDOX PROPERTIES OF RUTHENIUM COMPLEXES OF A TETRADENTATE BIS CHELATING LIGAND, 2,2'-AZOBIS(PYRIDINE)

The use of silver (I) assisted metal exchange reaction for the synthes is of mononuclear ruthenium (II) complexes of a tetradentate bridging ligand, 2,2'-azobis(pyridine) (L-1) is elaborated. This route has been successfully employed for the direct synthesis of RuCl2(L-1)(2) (2); [Ru(L-1)(3)](ClO4)(2) . H2O (3) from RuCl3 . 3H(2)O and for the mixed ligand tris chelates of general composition [Ru(L-1)(n)(L)(3-n)](2+) ( n = 0 - 3; L = neutral N,N donors: 2-(phenylazo)pyridine (L-2), 2,2'-b ipyridine (L-3)). The preparation of [Ru(OH2)(2)(L-1)(2)](2+) (7) from 2 is also described. The diaquo complex, 7, is chemically reactive an d undergoes anation, solvolysis and substitution reactions instantaneo usly with different nucleophiles. All the reactions, described above, occur smoothly and the yields of the products are high. The compositio n and identities of the complexes are established from their elemental analyses and spectral data. The redox properties of the compounds hav e been examined. Metal oxidation responses occur at very high positive potentials. Successive reductive responses occur on the negative of t he SCE.