0000000001304182
AUTHOR
Markus Gerhards
showing 16 related works from this author
Transient FTIR spectroscopy after one- and two-colour excitation on a highly luminescent chromium(III) complex.
2021
The development of photoactive transition metal complexes with Earth-abundant metals is a rapidly growing research field, where a deeper understanding of the underlying photophysical processes is of great importance. A multitude of potential applications in the fields of photosensitizing, optical sensing, photoluminescence and photoredox catalysis motivates demanding spectroscopic studies. We applied a series of high-level spectroscopic methods on the previously reported highly luminescent chromium(iii) complex [Cr(ddpd)2](BF4)3 (ddpd = N,N'-dimethyl-N,N'-dipyridine-2-ylpyridine-2,6-diamine) possessing two near-IR emissive doublet states with microsecond lifetimes. Luminescence measurements…
Deuterated Molecular Ruby with Record Luminescence Quantum Yield
2017
The recently reported luminescent chromium(III) complex 13+ ([Cr(ddpd)2]3+; ddpd=N,N’-dimethyl-N,N’-dipyridine-2-yl-pyridine-2,6-diamine) shows exceptionally strong near-IR emission at 775 nm in water under ambient conditions (F=11%) with a microsecond lifetime as the ligand design in 13+ effectively eliminates non-radiative decay pathways, such as photosubstitution, back-intersystem crossing, and trigonal twists. In the absence of energy acceptors, such as dioxygen, the remaining decay pathways are energy transfer to high energy solvent and ligand oscillators, namely OH and CH stretching vibrations. Selective deuteration of the solvents and the ddpd ligands probes the efficiency of these o…
Titelbild: Luminescence and Light‐Driven Energy and Electron Transfer from an Exceptionally Long‐Lived Excited State of a Non‐Innocent Chromium(III) …
2019
Deuterierter molekularer Rubin mit Rekord-Lumineszenzquantenausbeute
2018
Der kurzlich publizierte Chrom(III)-Komplex 13+([Cr(ddpd)2]3+) zeigt in wassriger Losung unter Umgebungsbedingungen eine bemerkenswert starke Emission im nahen Infrarot-Bereich mit einer Emissionswellenlange von 775 nm. Geschicktes Ligandendesign verhindert strahlungslose Desaktivierungsprozesse wie Photosubstitution, Ruck-Intersystem-Crossing und trigonale Verzerrungen und fuhrt damit zu einer Phosphoreszenzlebensdauer im Bereich von Mikrosekunden. In Abwesenheit von Energieakzeptoren wie molekularem Sauerstoff verbleibt nur Energietransfer zu hochenergetischen Oszillatoren der Liganden und Losungsmittelmolekule wie beispielsweise OH- und CH-Streckschwingungen als Desaktivierungspfad. Sele…
A Vanadium(III) Complex with Blue and NIR-II Spin-Flip Luminescence in Solution.
2020
Luminescence from Earth-abundant metal ions in solution at room temperature is a very challenging objective due to the intrinsically weak ligand field splitting of first-row transition metal ions, which leads to efficient nonradiative deactivation via metal-centered states. Only a handful of 3d
Spin Crossover and Long-Lived Excited States in a Reduced Molecular Ruby.
2020
Abstract The chromium(III) complex [CrIII(ddpd)2]3+ (molecular ruby; ddpd=N,N′‐dimethyl‐N,N′‐dipyridine‐2‐yl‐pyridine‐2,6‐diamine) is reduced to the genuine chromium(II) complex [CrII(ddpd)2]2+ with d4 electron configuration. This reduced molecular ruby represents one of the very few chromium(II) complexes showing spin crossover (SCO). The reversible SCO is gradual with T 1/2 around room temperature. The low‐spin and high‐spin chromium(II) isomers exhibit distinct spectroscopic and structural properties (UV/Vis/NIR, IR, EPR spectroscopies, single‐crystal XRD). Excitation of [CrII(ddpd)2]2+ with UV light at 20 and 290 K generates electronically excited states with microsecond lifetimes. This…
Strongly Red-Emissive Molecular Ruby [Cr(bpmp)2]3+ Surpasses [Ru(bpy)3]2+
2021
Gaining chemical control over the thermodynamics and kinetics of photoexcited states is paramount to an efficient and sustainable utilization of photoactive transition metal complexes in a plethora of technologies. In contrast to energies of charge transfer states described by spatially separated orbitals, the energies of spin-flip states cannot straightforwardly be predicted as Pauli repulsion and the nephelauxetic effect play key roles. Guided by multireference quantum chemical calculations, we report a novel highly luminescent spin-flip emitter with a quantum chemically predicted blue-shifted luminescence. The spin-flip emission band of the chromium complex [Cr(bpmp)2]3+ (bpmp = 2,6-bis(…
Luminescence and Light‐Driven Energy and Electron Transfer from an Exceptionally Long‐Lived Excited State of a Non‐Innocent Chromium(III) Complex
2019
Abstract Photoactive metal complexes employing Earth‐abundant metal ions are a key to sustainable photophysical and photochemical applications. We exploit the effects of an inversion center and ligand non‐innocence to tune the luminescence and photochemistry of the excited state of the [CrN6] chromophore [Cr(tpe)2]3+ with close to octahedral symmetry (tpe=1,1,1‐tris(pyrid‐2‐yl)ethane). [Cr(tpe)2]3+ exhibits the longest luminescence lifetime (τ=4500 μs) reported up to date for a molecular polypyridyl chromium(III) complex together with a very high luminescence quantum yield of Φ=8.2 % at room temperature in fluid solution. Furthermore, the tpe ligands in [Cr(tpe)2]3+ are redox non‐innocent, …
Ultrafast and long-time excited state kinetics of an NIR-emissive vanadium(iii) complex I: synthesis, spectroscopy and static quantum chemistry.
2021
In spite of intense, recent research efforts, luminescent transition metal complexes with Earth-abundant metals are still very rare owing to the small ligand field splitting of 3d transition metal complexes and the resulting non-emissive low-energy metal-centered states. Low-energy excited states decay efficiently non-radiatively, so that near-infrared emissive transition metal complexes with 3d transition metals are even more challenging. We report that the heteroleptic pseudo-octahedral d2-vanadium(iii) complex VCl3(ddpd) (ddpd = N,N′-dimethyl-N,N′-dipyridine-2-yl-pyridine-2,6-diamine) shows near-infrared singlet → triplet spin–flip phosphorescence maxima at 1102, 1219 and 1256 nm with a …
CCDC 1876390: Experimental Crystal Structure Determination
2019
Related Article: Steffen Treiling, Cui Wang, Christoph Fçrster, Florian Reichenauer, Jens Kalmbach, Pit Boden, Joe P. Harris, Luca M. Carrella, Eva Rentschler, Ute Resch-Genger, Christian Reber, Michael Seitz, Markus Gerhards, and Katja Heinze|2019|Angew.Chem.,Int.Ed.|58|18075|doi:10.1002/anie.201909325
CCDC 1989536: Experimental Crystal Structure Determination
2021
Related Article: Florian Reichenauer, Cui Wang, Christoph Förster, Pit Boden, Naz Ugur, Ricardo Báez-Cruz, Jens Kalmbach, Luca M. Carrella, Eva Rentschler, Charusheela Ramanan, Gereon Niedner-Schatteburg, Markus Gerhards, Michael Seitz, Ute Resch-Genger, Katja Heinze|2021|J.Am.Chem.Soc.|143|11843|doi:10.1021/jacs.1c05971
CCDC 1958562: Experimental Crystal Structure Determination
2020
Related Article: Matthias Dorn, Jens Kalmbach, Pit Boden, Ayla Päpcke, Sandra Gómez, Christoph Förster, Felix Kuczelinis, Luca M. Carrella, Laura A. Büldt, Nicolas H. Bings, Eva Rentschler, Stefan Lochbrunner, Leticia González, Markus Gerhards, Michael Seitz, Katja Heinze|2020|J.Am.Chem.Soc.|142|7947|doi:10.1021/jacs.0c02122
CCDC 2083757: Experimental Crystal Structure Determination
2021
Related Article: Florian Reichenauer, Cui Wang, Christoph Förster, Pit Boden, Naz Ugur, Ricardo Báez-Cruz, Jens Kalmbach, Luca M. Carrella, Eva Rentschler, Charusheela Ramanan, Gereon Niedner-Schatteburg, Markus Gerhards, Michael Seitz, Ute Resch-Genger, Katja Heinze|2021|J.Am.Chem.Soc.|143|11843|doi:10.1021/jacs.1c05971
CCDC 1958093: Experimental Crystal Structure Determination
2020
Related Article: Patrick B. Becker, Christoph Förster, Luca M. Carrella, Piet Boden, David Hunger, Joris van Slageren, Markus Gerhards, Eva Rentschler, Katja Heinze|2020|Chem.-Eur.J.|26|7199|doi:10.1002/chem.202001237
CCDC 1989537: Experimental Crystal Structure Determination
2021
Related Article: Florian Reichenauer, Cui Wang, Christoph Förster, Pit Boden, Naz Ugur, Ricardo Báez-Cruz, Jens Kalmbach, Luca M. Carrella, Eva Rentschler, Charusheela Ramanan, Gereon Niedner-Schatteburg, Markus Gerhards, Michael Seitz, Ute Resch-Genger, Katja Heinze|2021|J.Am.Chem.Soc.|143|11843|doi:10.1021/jacs.1c05971
CCDC 1876389: Experimental Crystal Structure Determination
2019
Related Article: Steffen Treiling, Cui Wang, Christoph Fçrster, Florian Reichenauer, Jens Kalmbach, Pit Boden, Joe P. Harris, Luca M. Carrella, Eva Rentschler, Ute Resch-Genger, Christian Reber, Michael Seitz, Markus Gerhards, and Katja Heinze|2019|Angew.Chem.,Int.Ed.|58|18075|doi:10.1002/anie.201909325