Excited State Dynamics of Bistridentate and Trisbidentate RuII Complexes of Quinoline-Pyrazole Ligands
Journal article, 2019

Three homoleptic ruthenium(II) complexes, [Ru(Q3PzH)3]2+, [Ru(Q1Pz)3]2+, and [Ru(DQPz)2]2+, based on the quinoline-pyrazole ligands, Q3PzH (8-(3-pyrazole)-quinoline), Q1Pz (8-(1-pyrazole)-quinoline), and DQPz (bis(quinolinyl)-1,3-pyrazole), have been spectroscopically and theoretically investigated. Spectral component analysis, transient absorption spectroscopy, density functional theory calculations, and ligand exchange reactions with different chlorination agents reveal that the excited state dynamics for Ru(II) complexes with these biheteroaromatic ligands differ significantly from that of traditional polypyridyl complexes. Despite the high energy and low reorganization energy of the excited state, nonradiative decay dominates even at liquid nitrogen temperatures, where triplet metal-to-ligand-charge-transfer emission quantum yields range from 0.7 to 3.8%, and microsecond excited state lifetimes are observed. In contrast to traditional polypyridyl complexes where ligand exchange is facilitated by expansion of the metal-ligand bonds to stabilize a metal-centered state, photoinduced ligand exchange occurs in the bidentate complexes despite no substantial MC state population, while the tridentate complex is extremely photostable despite an activated decay route, highlighting the versatile photochemistry of nonpolypyridine ligands. © 2019 American Chemical Society.


L. A. Fredin

Lund University

Lehigh University

Joachim Wallenstein

Chalmers, Physics, Materials Physics

Elin Sundin

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

M. Jarenmark

Lund University

Deise Fernanda Barbosa de Mattos

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

P. Persson

Lund University

Maria Abrahamsson

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Inorganic Chemistry

0020-1669 (ISSN) 1520-510X (eISSN)

Vol. 58 24 16354-16363

Subject Categories

Inorganic Chemistry

Atom and Molecular Physics and Optics

Theoretical Chemistry

Driving Forces

Sustainable development

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Nanoscience and Nanotechnology (SO 2010-2017, EI 2018-)

Materials Science


Basic sciences



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