Factorizing the Nephelauxetic Effect in Heteroleptic Molecular Rubies DOI

Florian Reichenauer,

Dimitri Zorn,

Robert Naumann

и другие.

Inorganic Chemistry, Год журнала: 2024, Номер unknown

Опубликована: Дек. 2, 2024

The interest in chromium(III) complexes has been renewed over the past decade for design of efficient earth-abundant phosphorescent red-to-near-infrared spin-flip emitters and photocatalysts with long excited state lifetimes. In this context, we report energy tuning states based on heteroleptic bis(tridentate) polypyridine [3X,Y]3+, namely, [3NMe,CH2]3+, [3NMe,S]3+ [3CH2,S]3+ tridentate ligands LX LY [X/Y = NMe, N,N′-dimethyl-N,N′-dipyridin-2-ylpyridine-2,6-diamine; X/Y CH2, 2,6-bis(2-pyridylmethyl)pyridine S, 2,6-bis(pyridine-2-ylthio)pyridine]. [3X,Y]3+ are obtained via a novel synthetic approach toward required intermediate labile triflato Cr(LX)(OTf)3 (2X) from respective chlorido precursors CrCl3(LX) (1X) using trimethylsilyl trifluoromethanesulfonate. Spin-flip energies were experimentally detected by vis/near-infrared absorption emission spectroscopy as well computationally derived multireference calculations. Together known homoleptic molecular ruby complexes, three resulting series luminescent [3X,X]3+/[3X,Y]3+/[3Y,Y]3+ allow delineation an additive nephelauxetic effect ions thus prediction rubies.

Язык: Английский

Thermally Activated Delayed Fluorescence (TADF) Materials Based on Earth‐Abundant Transition Metal Complexes: Synthesis, Design and Applications DOI Creative Commons
Valentina Ferraro, Claudia Bizzarri,

Stefan Bräse

и другие.

Advanced Science, Год журнала: 2024, Номер unknown

Опубликована: Июль 10, 2024

Materials exhibiting thermally activated delayed fluorescence (TADF) based on transition metal complexes are currently gathering significant attention due to their technological potential. Their application extends beyond optoelectronics, in particular organic light-emitting diodes (OLEDs) and electrochemical cells (LECs), include also photocatalysis, sensing, X-ray scintillators. From the perspective of sustainability, earth-abundant centers preferred rarer second- third-transition series elements, thus determining a reduction costs toxicity but without compromising overall performances. This review offers an overview TADF as photoconversion materials. Particular is devoted types ligands employed, helping design novel systems with enhanced properties.

Язык: Английский

Процитировано

12
Earth Abundant Transition Metals Complexes in Light-emitting Electrochemical Cells: Successes, Challenges and Perspectives DOI Creative Commons

Ginevra Giobbio,

Rubén D. Costa, Sylvain Gaillard

и другие.

Dalton Transactions, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

A journey on Earth abundant transition metal complexes as emiters for Light-emitting Electrochemical Cells.

Язык: Английский

Процитировано

0
Donor/Acceptor Ligands Based on an o-Terphenyl Motif to Achieve Thermally Activated Delayed Fluorescence in Zn(II) Complexes DOI

Darius A. Shariaty,

Jonas Schaab, Eric T. McClure

и другие.

Inorganic Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Янв. 14, 2025

The photophysical properties of six new luminescent tetrahedral Zn(II) complexes are presented that survey two electronic donor moieties (phenolate and carbazolate) three acceptors (pyridine, pyrimidine, pyrazine). A unique ligand based on an o-terphenyl motif forms eight-membered chelate, which enhances through-space charge-transfer (CT) interactions by limiting through-bond conjugation between the acceptor. single isomeric product was obtained in yields up to 90%. Single-crystal X-ray diffraction structures Zn incorporating either show complementary interligand π–π interactions. All display long-lived luminescence solid state consistent with emission involving triplet state. phenolate-based evidence CT only strongest (pyrazinyl) In contrast, all carbazolate-based thermally activated delayed fluorescence (TADF) solution state, photoluminescent quantum 39%. These ligands represent a family coordination compounds demonstrating TADF/phosphorescent expand upon elucidate design principles pursuit photoactive earth-abundant metal complexes.

Язык: Английский

Процитировано

0
Molecular Design Principles for Photoactive Transition Metal Complexes: A Guide for “Photo-Motivated” Chemists DOI Creative Commons
Giacomo Morselli, Christian Reber, Oliver S. Wenger

и другие.

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Март 27, 2025

Luminescence and photochemistry involve electronically excited states that are inherently unstable therefore spontaneously decay to electronic ground states, in most cases by nonradiative energy release generates heat. This dissipation can occur on a time scale of 100 fs (∼10–13 s) usually needs be slowed down at least the nanosecond (∼10–9 for luminescence intermolecular occur. is challenging task with many different factors consider. An alternative emerging strategy target dissociative lead metal–ligand bond homolysis subnanosecond access synthetically useful radicals. Based thorough review recent advances field, this article aims provide concise guide obtaining luminescent photochemically coordination compounds d-block elements. We hope encourage "photo-motivated" chemists who have been reluctant apply their synthetic other knowledge photophysics photochemistry, we intend stimulate new approaches control state behavior.

Язык: Английский

Процитировано

0
Metal complex-based TADF: design, characterization, and lighting devices DOI Creative Commons
Afsaneh Farokhi, Sophia Lipinski, Luca M. Cavinato

и другие.

Chemical Society Reviews, Год журнала: 2024, Номер unknown

Опубликована: Янв. 1, 2024

This review focuses on the state-of-the-art of organic light-emitting diodes (OLEDs) and electrochemical cells (LECs) prepared with transition metal complexes featuring thermally activated delayed fluorescence (TADF) mechanism.

Язык: Английский

Процитировано

3
Enhanced Thermally Activated Delayed Fluorescence by Sole Coordination: From an Organic Molecule to Its Zinc Complex DOI
Hao Deng, Tao Wang,

Yuannan Chen

и другие.

The Journal of Physical Chemistry Letters, Год журнала: 2024, Номер 15(27), С. 7003 - 7010

Опубликована: Июль 1, 2024

A BPAPTPyC organic molecule containing a sandwich structural chromophore is designed and synthesized to produce blue thermally activated delayed fluorescence (TADF). The composed of two di(4-tert-butylphenyl)amino donors one inserted terpyridyl acceptor hitched at positions 1, 8, 9 single carbazole via the p-phenylene group, in which multiple space π–π interactions between donor enable possess TADF feature with high energy emission 470 nm but low photoluminescence quantum yield (PLQY) small proportion component. In contrast, corresponding Zn(BPAPTPyC)Cl2 complex has PLQY short lifetime red-shifted due enhanced rigidity electron accepting ability group from coordination. solution-processed light-emitting diode (OLED) based on achieves maximum external efficiency (EQE) 17.9% an peak 585 nm, while OLED produces EQE 2.7%.

Язык: Английский

Процитировано

2
Thermally Activated Delayed Fluorescence and Beyond. Photophysics and Material Design Strategies. DOI Creative Commons
Hartmut Yersin, Uwe Monkowius

Advanced Photonics Research, Год журнала: 2024, Номер unknown

Опубликована: Сен. 2, 2024

This review focuses on thermally activated delayed fluorescence (TADF). Photophysical properties of Cu(I) complexes and unique organic molecules are addressed. Investigations, based temperature‐dependent emission studies, micro‐ to femto‐second time‐resolved spectroscopy investigations, quantum mechanical considerations, state‐of‐art calculations, light‐emitting diodes (OLED) device address exciton harvesting mechanisms photophysical impact the energy gap Δ E ( S 1 – T ) spin‐orbit coupling (SOC). We disclose relationship between (i) transition rate k 0 ); (ii) SOC, phosphorescence, intersystem crossing (ISC); (iii) internal/external rigidity, luminescence yield, excitation self‐trapping, concentration quenching; (iv) environment polarity state tuning, as well (v) SOC combined ambient‐temperature TADF/phosphorescence, zero‐field splitting, spin‐lattice relaxation (at = 1.2 K). These studies guide us milestone complexes. Moreover, we demonstrate that fast ISC in requires mixing with an additional, energetically close triplet state. Thus, a structure for TADF ultra‐fast reverse‐ISC rates (>10 9 s −1 )<10 cm (<1 meV) is presented allowing singlet‐triplet equilibrated sub‐microsecond decay. First OLEDs fabricated show high external efficiency ≈19%. Based this breakthrough material class, new mechanism, direct singlet (DSH), presented.

Язык: Английский

Процитировано

2
Toward the improvement of vibronic spectra and non-radiative rate constants using the vertical Hessian method DOI

Tobias Böhmer,

Martin Kleinschmidt, Christel M. Marian

и другие.

The Journal of Chemical Physics, Год журнала: 2024, Номер 161(9)

Опубликована: Сен. 5, 2024

For the computation of vibrationally resolved electronic spectra, various approaches can be employed. Adiabatic simulate vibronic transitions using harmonic potentials initial and final states, while vertical extrapolate state potential from gradients Hessian at Franck–Condon point, avoiding a full exploration energy surface state. Our implementation (VH) method has been validated with benchmark set four small molecules, each presenting unique challenges, such as complex topologies, problematic low-frequency vibrations, or significant geometrical changes upon excitation. We assess quality both adiabatic for simulating transitions. two types donor–acceptor compounds promising thermally activated delayed fluorescence properties, our computations confirm that outperform ones. The VH significantly reduces computational costs yields meaningful emission where models fail. More importantly, we pioneer use rate constants non-radiative processes, intersystem crossing reverse along relaxed interpolated pathway compound. This study highlights to advance spectroscopy by providing simulations intricate decay mechanisms in molecular systems.

Язык: Английский

Процитировано

2
Bridge Editing of Spin-Flip Emitters gives Insight into Excited State Energies and Dynamics DOI Creative Commons

Florian Reichenauer,

Robert Naumann, Christoph Förster

и другие.

Chemical Science, Год журнала: 2024, Номер 15(48), С. 20251 - 20262

Опубликована: Янв. 1, 2024

The bridge X of the chelate ligand modifies doublet and quartet state energies excited dynamics luminescent chromium( iii ) complexes.

Язык: Английский

Процитировано

2
Enhanced Intersystem Crossing, Yet Still Fluorescence Upon Introduction of Intermediate Charge-Transfer States in Hemicaged [Zn(bpy)3]2+ DOI

Julia Kuhnt,

Mousree Mitra,

Sabyasachi Maity

и другие.

The Journal of Physical Chemistry Letters, Год журнала: 2024, Номер 15(24), С. 6409 - 6414

Опубликована: Июнь 12, 2024

Photoactive zinc(II) complexes typically undergo fluorescence from the singlet excited state as dominant radiative pathway, operative spin–orbit coupling is usually very small and phosphorescence triplet strongly forbidden. Although dicationic tris(bipyridine) strictly follows this scheme with at λem = 326 nm, constructing ligand sphere a hemicage was reported to lead quantitative intersystem crossing (ISC) subsequent fast 485 short lifetime of ca. 1 μs. Surprised by finding, we reinvestigated [Zn(bpy)3]2+ its derivative in great detail, including variable temperature time-resolved photophysical measurements solution solid well high-level theoretical calculations resolve their behavior. Our investigations suggest that both compounds room significantly different rate constants kr 2 × 108 1.2 106 s–1, respectively, only weak on millisecond time scale low temperatures. The major difference occurrence additional charge-transfer states within scaffold hemicage, which accelerate ISC 3LC(bpy) 350 s down 82 ns reduce constant.

Язык: Английский

Процитировано

1