title: Aryl-Decorated Ru(II) Polypyridyl-type Photosensitizer Approaching NIR Emission with Microsecond Excited State Lifetimes.
abstract: Bis-tridentate Ru(II) complexes based on the dqp scaffold (dqp is 2,6-di(quinolin-8-yl)pyridine) with multiple aryl substituents were explored to tailor the absorption and emission properties. A synthetic methodology was developed for the facile synthesis and purification of homo- and heteroleptic bis-tridentate Ru complexes. The effect of the aryl substituents in the para positions of the pyridine and quinoline subunits was detailed by X-ray crystallography, steady state and time-resolved spectroscopy, electrochemistry, and computational methods. The attachment of the aryl groups results in enhanced molar extinction coefficients with the largest effect in the pyridine position, whereas the quinoline substituent leads to red-shifted emission tailing into the NIR region (up to 800 nm). Notably, the excited state lifetimes remain in the microsecond time scale even in the presence of O2, whereas the emission quantum yields are slightly increased with respect to the parental complex [Ru(dqp)2](2+). The peripheral functional groups (Br, Me, OMe) have only a minor impact on the optical properties and are attractive to utilize such complexes as functional building blocks.
authors.affiliation: Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena , Humboldtstraße 10, 07743 Jena, Germany.
authors.forename: Tina
authors.initials: T
authors.lastname: Schlotthauer
authors.affiliation: Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena , Humboldtstraße 10, 07743 Jena, Germany.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Suchland
authors.affiliation: Laboratory of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena , Lessingstraße 8, 07743 Jena, Germany.
authors.forename: Helmar
authors.initials: H
authors.lastname: Görls
authors.affiliation: Department of Chemistry - Ångström Laboratory, Uppsala University , Box 523, SE-75120 Uppsala, Sweden.
authors.forename: Giovanny A
authors.initials: GA
authors.lastname: Parada
authors.affiliation: Department of Chemistry - Ångström Laboratory, Uppsala University , Box 523, SE-75120 Uppsala, Sweden.
authors.forename: Leif
authors.initials: L
authors.lastname: Hammarström
authors.affiliation: Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena , Humboldtstraße 10, 07743 Jena, Germany.|Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena , Philosophenweg 7a, 07743 Jena, Germany.
authors.forename: Ulrich S
authors.initials: US
authors.lastname: Schubert
authors.affiliation: Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena , Humboldtstraße 10, 07743 Jena, Germany.|Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena , Philosophenweg 7a, 07743 Jena, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Jäger