Photoinduced electron transfer in supramolecular ruthenium–porphyrin assemblies

Abstract

We present dynamic supramolecular systems composed of a Ru(II) complex of the form of [Ru(dtBubpy)₂(qpy)][PF₆]₂ (where dtBubpy is 4,4′-di-tert-butyl-2,2′-dipyridyl and qpy is 4,4′:2′,2′′:4′′,4′′′-quaterpyridine) and zinc tetraphenylporphyrins (ZnTPP), through non-covalent interactions between the distal pyridine moieties of the qpy ligand and the zinc of ZnTPP. The optoelectronic properties of the assemblies and the electronic interactions between the chromophoric units have been comprehensively characterized by computational investigations, and steady-state and time-resolved emission spectroscopy. Upon photoexcitation of ZnTPP, electron transfer to the ruthenium center is thermodynamically favorable and, as a result, strong emission quenching of both units occurs.