Abstract
The reactions of ruthenium(III) chloride (1 mol) with acetylacetonylidene-4-aminoantipyrine (HL
1), monobenzoylacetylacetonylidene-4-aminoantipyrine (HL
2), dibenzoylmethanylidene-4-aminoantipyrine (HL
3) and antipyrine-4-azo-β-ethylacetoacetate (HL
4) (1 mol) produce complexes of the general formula RuHLCl
3. The ligand antipyrine-4-azo-β-acetylacetone (HL
5) (1 mol) reacts with RuCl
3·3H
2O to produce RuL
5 Cl
2(H
2O)·H
2O. The ligands HL
1-HL
3 react as neutral bidentates in the ketoenamine form, whereas HL
4 reacts as a neutral bidentate in the hydrazo form. HL
5 reacts as a monobasic tridentate in the azo form. The complexes were characterized using a variety of analytical, spectral, magnetic and thermal measurements. The electrochemical redox properties of complexes
I–V have been studied by cyclic voltammetry in acetonitrile. The chloro-bridged dimer complexes
I–IV showed two reversible diffusion-controlled oxidation peaks. The first was attributed to the oxidation of the ruthenium(III) to the corresponding mixed-valence complex and the second to the ruthenium(IV) complex. The redox properties of complexes
I–IV are dependent on the nature of ligand. The monomeric complex
V has quite different properties.