Synthesis and photophysics of ruthenium(ii) complexes with multiple pyrenylethynylene subunits

Abstract

We describe the synthesis and photophysical properties of new Ru(II) complexes bearing different numbers of pyrenylethynylene substituents in either the 5 or 5,5′ positions of 2,2′-bipyridine. Static and dynamic absorption and luminescence measurements reveal the nature of the lowest excited states in each molecule. The 5-substituted complexes display behavior dominated by triplet intraligand π,π* excited states, generating long-lived room temperature phosphorescence in the red. While the photophysical properties in the 5,5′-substituted case are still largely influenced by triplet intraligand π,π* excited states, the data suggest the possibility of an excited state manifold composed of “mixed” intraligand and charge transfer character.