Synthesis and characterisation of ruthenium polypyridyl complexes containing a pendent hydroquinone grouping

The synthesis of the ligand 1,4-dihydroxy-2,5-bis(3-(pyridin-2-yl)-1,2,4-triazol-1-yl)benzene (L1) and its mono and dinuclear rutheniumbis(2,2′-bipyridyl) complexes are reported. The compounds obtained are characterised by NMR, UV–Vis and emission spectroscopy and have also been studied by electrochemical and spectroelectrochemical techniques. The data obtained suggest that L1 is bound to the metal centre via the pyridine ring and the N4 atom of the triazole moiety. The compounds emit at room temperature and electrochemical studies show that the central hydroquinone unit is oxidised before the ruthenium centres.