Long-Lived Trimetallic Complexes of Fe(II), Ru(II), and Os(II) Basedon a Heteroditopic Bipyridine–Terpyridine Bridge: Synthesis,Photophysics, and Electronic Energy Transfer

Synthesis, characterization, and investigation of photophysical and redox behaviors of a new class of homo- and heterotrimetallic complexes of composition [(bpy/phen)2Ru(dipy-Hbzim-tpy)M(tpy-Hbzim-dipy)Ru(bpy/phen)2]6+ (M = FeII, RuII, and OsII) derived from a conjugated heteroditopic bipyridine–terpyridine bridge were carried out in this work. Trimetallic RuZnRu complexes of composition [(bpy/phen)2Ru(dipy-Hbzim-tpy)Zn(tpy-Hbzim-dipy)Ru(bpy/phen)2]6+ were also synthesized in situ as their photophysical properties are of particular interest in demonstrating the absorption and emission spectra of the complexes in the presence of a metal (Zn2+) that has neither metal-to-ligand charge transfer (MLCT) nor metal-centered (3MC) states. Complexes display intense absorption bands spanning almost the entire UV and visible region. The complexes also exhibit rich electrochemical behaviors with a number of metal-centered reversible oxidation and ligand-centered reduction waves. All complexes are luminescent at room t...