Luminescence and spectroscopic studies of organometallic rhodium and rhenium multichromophore systems carrying polypyridyl acceptor sites and phenylethynyl antenna subunits

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• 作者：Kerstin Oppelt^a ; Daniel. A.M. Egbe^b ; Uwe Monkowius^a ; Manuela List^c ; Manfred Zabel^d ; Niyazi S. Sariciftci^b ; Gü ; nther Knö ; r^a ; ^{guenther.knoer@jku.at}
• 关键词：Electronic spectra ; Luminescence ; Rhenium complexes ; Rhodium complexes ; Multichromophore systems ; Phenyleneethynylene ligands
• 刊名：Journal of Organometallic Chemistry
• 出版年：2011
• 出版时间：15 May 2011
• 年：2011
• 卷：696
• 期：10
• 页码：2252-2258
• 全文大小：635 K

文摘

The synthesis, structure, photophysics, and spectroscopic characterization of two novel organometallic rhodium and rhenium multichromophore photosensitizers carrying a central 2,2′-bipyridyl acceptor moiety are reported. Due to the presence of rigid phenylethynyl substituents in their 5,5′-position acting as intramolecular antenna groups, these compounds display perturbed excited state properties and a modified luminescence behaviour compared to the unsubstituted parent systems. The rhodium derivative is characterized by a weak blue–green intraligand (IL) phosphorescence occurring only at low temperatures. In the rhenium complex both a blue–green ligand-based luminescence and a red phosphorescence of metal-to-ligand charge transfer (MLCT) origin is observed at room temperature in solution. In rigid 77 K matrix the lowest-lying excited state levels approximate in energy and a structured luminescence band occurs which is ascribed to a ligand phosphorescence with admixed MLCT character.