TY - JOUR
A1 - Maisuls, I.
A1 - Wang, Cui
A1 - Gutierrez Suburu, M. E.
A1 - Wilde, S.
A1 - Daniliuc, C.-G.
A1 - Brunink, D.
A1 - Doltsinis, N. L.
A1 - Ostendorp, S.
A1 - Kösters, J.
A1 - Resch-Genger, Ute
A1 - Strassert, C. A.
T1 - Ligand-controlled and nanoconfinement-boosted luminescence employing Pt(II) and Pd(II) complexes: from color-tunable aggregation-enhanced dual emitters towards self-referenced oxygen reporters
JF - Chemical Science
N2 - In this work, we describe the synthesis, structural and photophysical characterization of four novel Pd(II) and Pt(II) complexes bearing tetradentate luminophoric ligands with high photoluminescence quantum yields (FL) and long excited state lifetimes (s) at room temperature, where the results were interpreted by means of DFT calculations. Incorporation of fluorine atoms into the tetradentate ligand favors aggregation and thereby, a shortened average distance between the metal centers, which provides accessibility to metal–metal-to-ligand charge-transfer (3MMLCT) excimers acting as red-shifted Energy traps if compared with the monomeric entities. This supramolecular approach provides an elegant way to enable room-temperature phosphorescence from Pd(II) complexes, which are otherwise quenched by a thermal population of dissociative states due to a lower ligand field splitting. Encapsulation of These complexes in 100 nm-sized aminated polystyrene nanoparticles enables concentration-controlled aggregation-enhanced dual emission. This phenomenon facilitates the tunability of the absorption and emission colors while providing a rigidified environment supporting an enhanced FL up to about 80% and extended s exceeding 100 ms. Additionally, these nanoarrays constitute rare examples for selfreferenced oxygen reporters, since the phosphorescence of the aggregates is insensitive to external influences, whereas the monomeric species drop in luminescence lifetime and intensity with increasing triplet molecular dioxygen concentrations (diffusion-controlled quenching).
KW - Fluorescence
KW - Multiplexing
KW - Lifetime
KW - Bead
KW - Particle
KW - Dye
KW - Barcoding
KW - Encoding
KW - Quantum yield
KW - Label
KW - Reporter
KW - Pd(II)
KW - Pt(II)
KW - Complex
KW - NMR
KW - X-ray
KW - Sythesis
KW - Aggregation
KW - Monomer
KW - Color
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525288
DO - https://doi.org/10.1039/d0sc06126c
VL - 12
IS - 9
SP - 3270
EP - 3281
PB - Royal Society of Chemistry
AN - OPUS4-52528
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reichenauer, F.
A1 - Wang, Cui
A1 - Förster, C.
A1 - Boden, P.
A1 - Ugur, N.
A1 - Báez-Cruz, R.
A1 - Kalmbach, J.
A1 - Carrella, L. M.
A1 - Rentschler, E.
A1 - Ramanan, C.
A1 - Niedner-Schatteburg, G.
A1 - Gerhards, M.
A1 - Seitz, M.
A1 - Resch-Genger, Ute
A1 - Heinze, K.
T1 - Strongly Red-Emissive Molecular Ruby [Cr(bpmp)2]3+ Surpasses [Ru(bpy)3]2+
JF - Journal of th American Chemical Society
N2 - 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 spinflip 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(2-pyridylmethyl) pyridine) shifted to higher energy from ca. 780 nm observed for known highly emissive chromium(III) complexes to 709 nm. The photoluminescence quantum yields climb to 20%, and very long excited state lifetimes in the millisecond range are achieved at room temperature in acidic D2O solution. Partial ligand deuteration increases the quantum yield to 25%. The high excited state energy of [Cr(bpmp)2]3+ and its facile reduction to [Cr(bpmp)2]2+ result in a high excited state redox potential. The ligand’s methylene bridge acts as a Brønsted acid quenching the luminescence at high pH. Combined with a pH-insensitive chromium(III) emitter, ratiometric optical pH sensing is achieved with single wavelength excitation. The photophysical and Ground state properties (quantum yield, lifetime, redox potential, and acid/base) of this spin-flip complex incorporating an earth-abundant metal surpass those of the classical precious metal [Ru(α-diimine)3]2+ charge transfer complexes, which are commonly employed in optical sensing and photo(redox) catalysis, underlining the bright future of these molecular ruby analogues.
KW - Fluorescence
KW - Optical probe
KW - Sensor
KW - PH
KW - Quantum yield
KW - Quality assurance
KW - Complex
KW - Cr(III)
KW - Lifetime
KW - Ligand
KW - Theory
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530548
DO - https://doi.org/10.1021/jacs.1c05971
VL - 143
IS - 30
SP - 11843
EP - 11855
PB - ACS Publications
AN - OPUS4-53054
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
ED - Wang, Cui
ED - Otto, S.
ED - Dorn, M.
ED - Kreidt, E.
ED - Lebon, J.
ED - Srsan, L.
ED - di Martino-Fumo, P.
ED - Gerhards, M.
ED - Seitz, M.
ED - Heinze, K.
T1 - Deuterierter molekularer Rubin mit Rekord-Lumineszenzquantenausbeute
JF - GDCh Angewandte Chemie
N2 - Der kürzlich publizierte Chrom(III)-Komplex 13+([Cr(ddpd)2]3+) zeigt in wässriger Lösung unter Umgebungsbedingungen eine bemerkenswert starke Emission im nahen Infrarot-Bereich mit einer Emissionswellenlänge von 775 nm.
Geschicktes Ligandendesign verhindert strahlungslose Desaktivierungsprozesse wie Photosubstitution, Rück-Intersystem-Crossing und trigonale Verzerrungen und führt damit zu einer Phosphoreszenzlebensdauer im Bereich von Mikrosekunden.
In Abwesenheit von Energieakzeptoren wie molekularem Sauerstoff verbleibt nur Energietransfer zu hochenergetischen Oszillatoren der Liganden und Lösungsmittelmoleküle wie beispielsweise OH- und CH-Streckschwingungen als Desaktivierungspfad. Selektive Deuterierung der ddpd-Liganden und der Lösungsmittel l-sst die Effizienz dieser Oszillatoren bei der Desaktivierung angeregter Zustände erkennbar werden. Gezieltes Ausschalten dieser Relaxationspfade führt zu einer Quantenausbeute von 30% und einer Lebensdauer von 2.3 Millisekunden bei Raumtemperatur in Lösung – Rekordwerte für einen Komplex, der auf dem Element Chrom basiert. Diese fundamentalen Erkenntnisse ebnen den Weg für gezieltes Ligandendesign zur Synthese lumineszierender Komplexe mit gut verfügbaren Übergangsmetallen.
KW - Fluorescence
KW - Quantum yield
KW - Ligand design
KW - Cr(III)
KW - Complex
KW - Oxygen sensor
KW - NIR
KW - Fluorescence lifetime
PY - 2018
DO - https://doi.org/10.1002/ange.201711350
SN - 1521-3757
VL - 130
IS - 4
SP - 1125
EP - 1130
PB - Wiley-VCH Verlag & Co. KGaA
CY - Weinheim
AN - OPUS4-44043
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
ED - Wang, Cui
ED - Otto, S.
ED - Dorn, M.
ED - Kreidt, E.
ED - Lebon, J.
ED - Srsan, L.
ED - di Martino-Fumo, P.
ED - Gerhards, M.
ED - Seitz, M.
ED - Heinze, K.
T1 - Deuterated Molecular Ruby with Record Luminescence Quantum Yield
JF - GDCh
N2 - 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 oscillators in the excited state deactivation. Addressing these energytransfer pathways in the first and second coordination sphere furnishes a record 30% quantum yield and a 2.3 millisecond lifetime for a metal complex with an earth-abundant metal ion in solution at room temperature.
KW - Fluorescence
KW - Quantum yield
KW - Ligand design
KW - Cr(III)
KW - Complex
KW - Oxygen sensor
KW - NIR
KW - Fluorescence lifetime
PY - 2018
DO - https://doi.org/10.1002/ange.201711350
SN - 1521-3773
VL - 57
IS - 4
SP - 1112
EP - 1116
PB - Wiley-VCH Verlag & Co. KGaA
CY - Weinheim
AN - OPUS4-44045
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Cui
A1 - Kitzmann, W.R.
A1 - Weigert, Florian
A1 - Förster, Ch.
A1 - Wang, X.
A1 - Heintze, K.
A1 - Resch-Genger, Ute
T1 - Matrix Effects on Photoluminescence and Oxygen Sensitivity of a Molecular Ruby
JF - ChemPhotoChem
N2 - The molecular ruby analogue [Cr(ddpd)2]3+ (ddpd=N,N’-dimethyl-N,N’-dipyridine-2-ylpyridine-2,6-diamine) exhibits near infrared (NIR) emission with a high photoluminescence (PL) quantum yield ΦPL of 11 % and a lifetime of 898 μs in deaerated water at room temperature. While ligand-based control of the photophysical properties has received much attention, influences of the counter anions and microenvironment are still underexplored. In this study, the luminescence properties of the molecular ruby were systematically examined for the counter anions Cl−, Br−, [BF4]−, [PF6]−, [BPh4]−, and [BArF24]− in acetonitrile (MeCN) solution, in crystals, and embedded into polystyrene nanoparticles (PSNP). Stern-Volmer analyses of the oxygen quenching studies in the intensity and lifetime domain showed the highest oxygen sensitivity of the complexes with the counter anions of [BF4]− and [BArF24]−, which also revealed the longest luminescence lifetimes. Embedding [Cr(ddpd)2][PF6]3 in PSNPs and shielding with poly(vinyl alcohol) yields a strongly NIR-emissive oxygen-insensitive material with a record ΦPL of 15.2 % under ambient conditions.
KW - Fluorescence
KW - Sensor
KW - Oxygen
KW - Quantum yield
KW - Quality assurance
KW - Complex
KW - Cr(III)
KW - Lifetime
KW - Ligand
KW - Solid state
KW - X-Ray analysis
KW - Structure-property relationship
KW - Nano
KW - Polymer
KW - Particle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546057
DO - https://doi.org/10.1002/cptc.202100296
SN - 2367-0932
VL - 6
IS - 6
SP - 1
EP - 9
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54605
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zuffa, Caterina
A1 - Cappuccino, Chiara
A1 - Casali, Lucia
A1 - Emmerling, Franziska
A1 - Maini, Lucia
T1 - Liquid reagents are not enough for liquid assisted grinding in the synthesis of (AgBr)(n-pica) n
JF - Physical Chemistry Chemical Physics
N2 - This study investigates the mechanochemical reactions between AgBr 3-picolylamine and 4-picolylamine. The use of different stoichiometry ratios of the reagents allows [(AgBr)(n-pica)]n and [(AgBr)2(n-pica)]n to be obtained, and we report the new structures of [(AgBr)2(3-pica)]n and [(AgBr)2(4-pica)]n which are characterized by the presence of the following: (a) infinite inorganic chains, (b) silver atom coordinated only by bromide atoms and (c) argentophilic interactions. Furthermore, we studied the interconversion of [(AgBr)(n-pica)]n/[(AgBr)2(n-pica)]n by mechanochemical and thermal properties. The in situ experiments suggest that [(AgBr)(3-pica)]n is kinetically favoured while [(AgBr)2(3-pica)]n is converted into [(AgBr)(3-pica)]n only with a high excess of the ligand. Finally, the liquid nature of the ligands is not sufficient to assist the grinding process, and the complete reaction is observed with the addition of a small quantity of acetonitrile.
KW - Mechanochemistry
KW - Complex
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594755
DO - https://doi.org/10.1039/d3cp04791a
SN - 1463-9076
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59475
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -