Stable Molybdenum(0) Carbonyl Complex for Upconversion and Photoredox Catalysis

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(30), С. 16597 - 16609

Опубликована: Июль 21, 2023

Photoactive complexes with earth-abundant metals have attracted increasing interest in the recent years fueled by promise of sustainable photochemistry. However, sophisticated ligands complicated syntheses are oftentimes required to enable photoactivity nonprecious metals. Here, we combine a cheap metal simple easily access photoactive complex. Specifically, synthesize molybdenum(0) carbonyl complex Mo(CO)3(tpe) featuring tripodal ligand 1,1,1-tris(pyrid-2-yl)ethane (tpe) two steps high overall yield. The shows intense deep-red phosphorescence excited state lifetimes several hundred nanoseconds. Time-resolved infrared spectroscopy and laser flash photolysis reveal triplet metal-to-ligand charge-transfer (3MLCT) as lowest state. Temperature-dependent luminescence complemented density functional theory (DFT) calculations suggest thermal deactivation 3MLCT via higher lying metal-centered states analogy well-known photophysics [Ru(bpy)3]2+. Importantly, found that title compound is very photostable due lack labilized Mo-CO bonds (as caused trans-coordinated CO) facial configuration ligands. Finally, show versatility applications: (1) green-to-blue photon upconversion triplet-triplet annihilation mechanism (2) photoredox catalysis for green-light-driven dehalogenation reaction. Overall, our results establish promising design strategy stable avoiding tedious multistep syntheses.

Язык: Английский

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Direct Evidence for Excited Ligand Field State-based Oxidative Photoredox Chemistry of a Cobalt(III) Polypyridyl Photosensitizer

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(38), С. 20786 - 20791

Опубликована: Сен. 13, 2023

Increasing interest in sustainable chemistry coupled with the quest to explore new reactivity has spurred research on first-row transition metal complexes for potential applications a variety of settings. One more active areas is photoredox catalysis, where synthetically tunable nature their electronic structures provides rich palette options tailoring desired chemical transformation. Understanding mechanism excited-state critical informed development next-generation catalysts, which turn requires information concerning propensity excited states engage electron or energy transfer processes. Herein we provide direct evidence highly oxidizing lowest-energy ligand-field (LF) state d6-low-spin Co(III) photosensitizer [Co(4,4′-Br2bpy)3]3+ (where 4,4′-Br2bpy 4,4′-dibromo-2,2′-bipyridine). The redox associated LF complex was bracketed by performing bimolecular quenching studies using series simple organic donors. Time-resolved absorption spectroscopy confirmed dynamic process attributed reductive chromophore. Analysis Stern–Volmer plots each chromophore-quencher pair revealed limiting value Ered* ∼ 1.25 V vs Fc/Fc+ metal-centered state, significantly stronger than that commonly employed metal-based agents such as [Ru(bpy)3]2+ (Ered* = 0.32 Fc/Fc+) and [Ir(ppy)2(bpy)]+ 0.27 Fc/Fc+). These results suggest this class chromophores could find utility requiring activation oxidatively resistant substrates catalysis.

Язык: Английский

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LNL-Carbazole Pincer Ligand: More than the Sum of Its Parts

Chemical Reviews, Год журнала: 2023, Номер 123(13), С. 8781 - 8858

Опубликована: Июнь 23, 2023

The utility of carbazole in photo-, electro-, and medicinal applications has ensured its widespread use also as the backbone tridentate pincer ligands. In this review, aim is to identify illustrate key features LNL-carbazolide binding transition metal centers (with L = flanking donor moieties, e.g., C, N, P, O-groups) a systematic bottom-up progression marked benefits attainable from (i) rigid aromatic scaffold (modulable both 1,8- 3,6-positions), (ii) significant electronic effect central carbazole-amido metal, tunable sterics electronics (iii) L-moieties (iv) wingtip R-groups on L-donors, with their corresponding influence coordination geometry, d-electron configuration, resultant reactivity. Systematic implementation ligand design strategies not isolation, but combinatorial approach, showcased demonstrate potential for functional molecules that are only modulable adaptable wide-ranging (e.g., stereoselective (photo)catalysis, challenging small molecule activation, SET redox applications, even chemotherapeutics) an indication future research efforts anticipated stem versatile assembly, metals s-, p-, f-block elements.

Язык: Английский

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Structural Control of Highly Efficient Thermally Activated Delayed Fluorescence in Carbene Zinc(II) Dithiolates**

Angewandte Chemie International Edition, Год журнала: 2023, Номер 63(7)

Опубликована: Дек. 8, 2023

Abstract Luminescent metal complexes based on earth abundant elements are a valuable target to substitute 4d/5d transition as triplet emitters in advanced photonic applications. Whereas Cu I have been thoroughly investigated the last two decades for this purpose, no structure‐property‐relationships efficient luminescence involving excited states from Zn II established. Herein, we report design of monomeric carbene zinc(II) dithiolates (CZT) featuring donor‐acceptor‐motif that leads highly thermally activated delayed fluorescence (TADF) with compounds unprecedented radiative rate constants k TADF =1.2×10 6 s −1 at 297 K. Our high‐level DFT/MRCI calculations revealed relative orientation ligands involved ligand‐to‐ligand charge transfer ( 1/3 LLCT) is paramount control process. Specifically, dihedral angle 36–40° very reverse intersystem‐crossing (rISC) order 10 9 due spin‐orbit coupling (SOC) mediated by sulfur atoms combination small ΔE S1‐T1 ca. 56 meV.

Язык: Английский

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The energy gap law for NIR-phosphorescent Cr(iii) complexes

Dalton Transactions, Год журнала: 2022, Номер 52(9), С. 2561 - 2565

Опубликована: Окт. 28, 2022

A series of homoleptic Cr(III) complexes containing substituted anionic 1,3-bis(pyridin-2-ylimino)isoindolin-2-ide ligands are phosphorescent with λmax in the 777-970 nm range degassed fluid solutions. The energy gap law has been successfully applied to doublet excited states complexes.

Язык: Английский

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Circularly polarized near-infrared phosphorescence of chiral chromium(iii) complexes

Chemical Communications, Год журнала: 2023, Номер 59(13), С. 1781 - 1784

Опубликована: Янв. 1, 2023

Homoleptic Cr(III) complexes containing anionic tridentate 1,8-(bisoxazolyl)carbazolide ligands are phosphorescent in deaerated solutions with peak maxima the range of 813-845 nm. The ligand carbon-centred chirality has been transferred to helical and hence induced circularly polarized NIR-emissions dissymmetry factor scale 2.0 × 10-3.

Язык: Английский

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Establishing the origin of Marcus-inverted-region behaviour in the excited-state dynamics of cobalt(III) polypyridyl complexes

Nature Chemistry, Год журнала: 2024, Номер 16(10), С. 1665 - 1672

Опубликована: Июль 4, 2024

Язык: Английский

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Picosecond Metal-to-Ligand Charge-Transfer Deactivation in Co(ppy)₃ via Jahn–Teller Distortion

Inorganic Chemistry, Год журнала: 2024, Номер 63(30), С. 13825 - 13830

Опубликована: Июль 18, 2024

The excited-state dynamics of

Язык: Английский

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Exploring the Photophysics and Photocatalytic Activity of Heteroleptic Rh(III) Transition-Metal Complexes Using High-Throughput Experimentation

Inorganic Chemistry, Год журнала: 2024, Номер 63(31), С. 14267 - 14277

Опубликована: Июль 20, 2024

High-throughput synthesis and screening (HTSS) methods were used to investigate the photophysical properties of 576 heteroleptic Rh(III) transition-metal complexes through measurement UV–visible absorption spectra, deaerated excited-state lifetime, phosphorescent emission spectra. While 4d photophysics are often highly influenced by deleterious metal-centered deactivation channels, HTSS structurally diverse cyclometalating ancillary ligands attached metal center facilitated discovery photoactive exhibiting long-lived charge-transfer phosphorescence (0.15–0.95 μs) spanning a substantial portion visible region (546–620 nm) at room temperature. Further electrochemical investigations then carried out on select with favorable understand underlying features controlling these superior properties. Heteroleptic Ir(III) identical ligand morphology also synthesized compare this family well understood chromophores. A number contained requisite for photocatalytic activity consequently tested as photocatalysts (PCs) in water reduction system using Pd cocatalyst. Under certain conditions, PC actually surpassed that PC, uncovering potential often-overlooked class transition metals both efficient chromophores PCs.

Язык: Английский

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Shifting the MLCT of d6 metal complexes to the red and NIR

Coordination Chemistry Reviews, Год журнала: 2025, Номер 530, С. 216454 - 216454

Опубликована: Фев. 3, 2025

Язык: Английский

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