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Author: Görls, Helmar × End date: 2023 × Start date: 2020 × DDC: 660 × Has files: Yes × WGL Institute: IPHT ×

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    Photophysics of Anionic Bis(4H-imidazolato)CuI Complexes
    (Weinheim : Wiley-VCH, 2022) Seidler, Bianca; Tran, Jens H.; Hniopek, Julian; Traber, Philipp; Görls, Helmar; Gräfe, Stefanie; Schmitt, Michael; Popp, Jürgen; Schulz, Martin; Dietzek‐Ivanšić, Benjamin
    In this paper, the photophysical behavior of four panchromatically absorbing, homoleptic bis(4H-imidazolato)CuI complexes, with a systematic variation in the electron-withdrawing properties of the imidazolate ligand, were studied by wavelength-dependent time-resolved femtosecond transient absorption spectroscopy. Excitation at 400, 480, and 630 nm populates metal-to-ligand charge transfer, intraligand charge transfer, and mixed-character singlet states. The pump wavelength-dependent transient absorption data were analyzed by a recently established 2D correlation approach. Data analysis revealed that all excitation conditions yield similar excited-state dynamics. Key to the excited-state relaxation is fast, sub-picosecond pseudo-Jahn-Teller distortion, which is accompanied by the relocalization of electron density onto a single ligand from the initially delocalized state at Franck-Condon geometry. Subsequent intersystem crossing to the triplet manifold is followed by a sub-100 ps decay to the ground state. The fast, nonradiative decay is rationalized by the low triplet-state energy as found by DFT calculations, which suggest perspective treatment at the strong coupling limit of the energy gap law.
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    1,7,9,10-Tetrasubstituted PMIs Accessible through Decarboxylative Bromination: Synthesis, Characterization, Photophysical Studies, and Hydrogen Evolution Catalysis
    (Weinheim : Wiley-VCH, 2020) Costabel, Daniel; Skabeev, Artem; Nabiyan, Afshin; Luo, Yusen; Max, Johannes B.; Rajagopal, Ashwene; Kowalczyk, Daniel; Dietzek, Benjamin; Wächtler, Maria; Görls, Helmar; Ziegenbalg, Dirk; Zagranyarski, Yulian; Streb, Carsten; Schacher, Felix H.; Peneva, Kalina
    In this work, we present a new synthetic strategy for fourfold-substituted perylene monoimides via tetrabrominated perylene monoanhydrides. X-ray diffraction analysis unveiled the intramolecular stacking orientation between the substituents and semicircular packing behavior. We observed the remarkable influence of the substituent on the longevity and nature of the excited state upon visible light excitation. In the presence of poly(dehydroalanine)-graft-poly(ethylene glycol) graft copolymers as solubilizing template, the chromophores are capable of sensitizing [Mo3S13]2− clusters in aqueous solution for stable visible light driven hydrogen evolution over three days. © 2020 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH