A ππ∗ State Enables Photoaccumulation of Charges on a π-Extended Dipyridophenazine Ligand in a Ru(II) Polypyridine Complex

Schindler J, Zhang Y, Traber P, Lefebvre JF, Kupfer S, Demeunynck M, Gräfe S, Chavarot-Kerlidou M, Dietzek B (2018)

Publication Type: Journal article

Publication year: 2018

Journal

Journal of Physical Chemistry C American Chemical Society

Book Volume: 122

Pages Range: 83-95

Journal Issue: 1

DOI: 10.1021/acs.jpcc.7b08989

Abstract

The π-extended dipyrido[3,2-a:2′,3′-c]phenazine (dppz) ligand of the Ru(II) complex [Ru(bpy)2(oxo-dppqp)](PF6)2 (oxo-dppqp = dipyrido[3,2-a:2′,3′-c]pyrido[2″,3″-4,5,6]quinolino[2,3-h]phenazin-15-one, bpy = 2,2′-bipyridine) enables the mononuclear complex for visible-light-driven accumulation of two electrons on a single ligand structure. Although this has been shown before, the excited-state physics underlying this promising feature are exploited in this work. The photophysics of the complex was investigated by excitation-wavelength-dependent resonance Raman and transient absorption spectroscopy in combination with time-dependent density functional theory. The results show that excitation with visible light leads to the population of the two excited-state branches: (i) the population of a short-lived 3MLCT state in which the excess electronic density is localized on the pyridoquinolinone moiety of the extended ligand (τ = 105 ps) and (ii) the population of a more long-lived 3ππ∗ state (τ = 9 ns). Notably, the long-lived 3ππ∗ state rather than a 3MLCT state is prone to reductive quenching by the sacrificial electron donor and, hence, presents the critical excited-state intermediate in the photochemical charge accumulation experiments.

Involved external institutions

Friedrich-Schiller-Universität Jena DE Germany (DE) University of Grenoble Alpes (UGA) / Université de Grenoble FR France (FR)

How to cite

APA:

Schindler, J., Zhang, Y., Traber, P., Lefebvre, J.-F., Kupfer, S., Demeunynck, M.,... Dietzek, B. (2018). A ππ∗ State Enables Photoaccumulation of Charges on a π-Extended Dipyridophenazine Ligand in a Ru(II) Polypyridine Complex. Journal of Physical Chemistry C, 122(1), 83-95. https://doi.org/10.1021/acs.jpcc.7b08989

MLA:

Schindler, Julian, et al. "A ππ∗ State Enables Photoaccumulation of Charges on a π-Extended Dipyridophenazine Ligand in a Ru(II) Polypyridine Complex." Journal of Physical Chemistry C 122.1 (2018): 83-95.

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