Synthesis, Photophysical and Electrochemical Properties of Novel Ru(II) Complexes

Abstract

Tremendous interest has been attracted to ruthenium (II) polypyridyl complexes because of their potential applications in molecular electronic devices, DNA structural probes, new therapeutic agents and photosensitizers in the conversion of solar energy to chemical or electrical energy. Over the past decade, a large amount of data has accumulated on changes in the electrochemical and photophysical properties of complexes effected by substitution in the 2,2'-bipyridine (bpy) and by replacement of one or two pyridine rings with other nitrogen-containing heterocycles. Based on the earlier studies and recent findings on ruthenium(II) heteroleptic complexes, it has been shown that the electrochemical and photophysical properties of ruthenium(II) complexes are not only dependent on the spatial geometry and molecular aggregation in the molecules, but also other factors such as the extended π-conjugation of the ligands also play major roles. This paper is dedicated to the synthesis of three new Ru(II) complexes with different extended conjugated moieties attached through auxiliary unit. The three ruthenium(II) complexes in DMF solution exhibit strong emission bands centered at 621, 607, and 603 nm, respectively, indicating that they are excellent red and orange light-emitting materials.