SPECTROSCOPIC AND ELECTROCHEMICAL STUDIES OF TWO BINUCLEAR RHENIUM (I) COMPLEXES

Abstract

 Rhenium(I) complexes of 1,4-bis(4'-methyl-2,2'-bipyrid-4-yl)buta-1,3-diene and 1,4-bis(4'-methyl-2,2'- bipyrid-4-yl)benzeneligands,hereafter denoted as bbdb and bphb respectively,were synthesised, characterised, and investigated for redox and luminescence properties involving ligand-localized phosphorescence with the aim of verifying their ability in photosensitization.The expected ligand localized phosphorescence was not observed in the bbdb complex, most probably due to the flexibility of the bridging ligand. The ligand itself shows no luminesce in room temperature solutions, but at 77 K, it exhibits fluorescence with no structured phosphorescence even in the presence of ethyl iodide. The bphbcomplex,however, exhibits phosphorescence at 77 K, but the ligand does not show structured phosphorescence, suggesting the bphbcomplexa good candidatefor photosensitizer application. These complexes showedirreversible oxidative cyclic voltammograms and the reductive cyclic voltammogramsconsist of several overlapping waves, indicating aggregation of the complexes at the electrode surfaceand reduction of the bridging-ligand.