Synthesis, spectroscopic and electrochemical properties of some heteroleptic tris-chelates of ruthenium (II) involving 2,2′-bipyridine (bpy) and N-(aryl) pyridine-2-aldimine(L): X-ray crystal structures of [Ru(bpy)(L2)2](ClO4)2 · H2O and 3-N(4-tolyl)

Reactions of 'Ru(bpy)Cl3' with N-(aryl) pyridine-2-aldimine(L) afford the heteroleptic tris chelate metal complex of the formula [Ru(bpy)(L)2](ClO4)2 · H2O (A) along with an unusual organic compound, 3-N(4-aryl) imidazo [1,5a] pyridinium perchlorate (B). One representative member of each has been characterized by X-ray crystallography. All the complexes undergo a quasi-reversible oxidation at ∼1.3 to 1.4 V, which may be assigned to a Ru(II) to Ru(III) oxidation. The visible region of the electronic spectra of the complexes consists of a weak transition at ∼630 nm and a broad envelope from 600 to 375 nm. 3-N(4-Tolyl) imidazo [1,5a] pyridinium perchlorate exhibits luminescence, with a strong emission at ∼380 nm.