Electronic Coupling between Two Cyclometalated Ruthenium Centers Bridged by 1,3,6,8-Tetra(2-pyridyl)pyrene (tppyr)

A new cyclometalating bridging ligand 1,3,6,8-tetra(2-pyridyl)pyrene was designed and synthesized through 4-fold Suzuki couplings between 1,3,6,8-tetrabromopyrene and 2-pyridylboronate. A bis-cyclometalated bisruthenium complex bridged by this ligand showed the presence of an electronic coupling between individual metal centers, as indicated by electrochemical and spectroscopic studies.