SPECTRAL AND ELECTROCHEMICAL PROPERTIES OF THE DIASTEREOISOMERIC FORMS OF AZOBIS(2-PYRIDINE)-BRIDGED DIRUTHENIUM SPECIES

A series of dinuclear complexes of ruthenium(II) have been synthesized in which alpha-azodiimines {such as azobis-(2-pyridine), apy, and azo bis(4-methyl-2-pyridine), mapy} act as the bridge and 2,2'-bipyridine (bpy) or 4,4'-dimethyl-2,2'-bipyridine (Me(2)bpy) as the terminal liga nds. The diastereoisomeric forms of each species {Delta Lambda (meso) and Delta Delta/Lambda Lambda (rac)} have been separated by cation-exc hange chromatography and characterized by H-1-NMR spectroscopy. Electr onic spectral and electrochemical studies show then to be differences in inter-metal communication between the diastereoisomeric forms in ea ch case. Comparison of the spectroelectrochemical behavior of the rang e of complexes has allowed unequivocal assignment of the site of the s uccessive reduction processes observed in dinuclear complexes of this type.