Photoactive Metal-to-Ligand Charge Transfer Excited States in 3d⁶ Complexes with Cr⁰, Mn^I, Fe^II, and Co^III

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(9), P. 4903 - 4920

Published: Feb. 21, 2023

Many coordination complexes and organometallic compounds with the 4d6 5d6 valence electron configurations have outstanding photophysical photochemical properties, which stem from metal-to-ligand charge transfer (MLCT) excited states. This substance class makes extensive use of most precious least abundant metal elements, consequently there has been a long-standing interest in first-row transition photoactive MLCT Semiprecious copper(I) its completely filled 3d subshell is relatively straightforward well explored case, but 3d6 partially d-orbitals lead to energetically low-lying metal-centered (MC) states that can cause undesirably fast state deactivation. Herein, we discuss recent advances made isoelectronic Cr0, MnI, FeII, CoIII compounds, for long-lived become accessible over past five years. Furthermore, possible future developments search new subshells next-generation applications photophysics photochemistry.

Language: Английский

---

Photoredox-active Cr(0) luminophores featuring photophysical properties competitive with Ru(II) and Os(II) complexes

Nature Chemistry, Journal Year: 2023, Volume and Issue: 15(12), P. 1730 - 1736

Published: Aug. 14, 2023

Coordination complexes of precious metals with the d6 valence electron configuration such as Ru(II), Os(II) and Ir(III) are used for lighting applications, solar energy conversion photocatalysis. Until now, made from abundant first-row transition competitive photophysical photochemical properties have been elusive. While previous research efforts focused mostly on Fe(II), we disclose that isoelectronic Cr(0) gives access to higher photoluminescence quantum yields excited-state lifetimes when compared any other metal complex reported so far. The luminescence behaviour metal-to-ligand charge transfer excited states these is polypyridines. With complexes, become exploitable in photoredox catalysis, benchmark chemical reductions proceed efficiently under low-energy red illumination. Here demonstrate appropriate molecular design strategies open up new perspectives photophysics photochemistry metals.

Language: Английский

---

A new era of LMCT: leveraging ligand-to-metal charge transfer excited states for photochemical reactions

Chemical Science, Journal Year: 2024, Volume and Issue: 15(18), P. 6661 - 6678

Published: Jan. 1, 2024

Ligand-to-metal charge transfer (LMCT) excited states showcase promise in enabling photochemical reactions. This article details design principles to enable low energy LMCT and notable examples that drive reactions from these states.

Language: Английский

---

NIR‐Circularly Polarized Luminescence from Chiral Complexes of Lanthanides and d‐Metals

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(25)

Published: March 22, 2023

Abstract In recent years, circularly polarized luminescence (CPL) has witnessed a renaissance, due to the increased popularity of CPL as spectroscopic technique and greater accessibility instrumentation. New efficient emitters have been designed many applications, ranging from electronic devices microscopy proposed. Most examples are within visible range, while few cases near infrared (NIR) active complexes available. NIR‐CPL compounds may applications in telecommunication industry, bioassays. following, we shall give an overview developments allowing for measurements NIR‐CPL, describe chiroptical properties metal which achieve this feat.

Language: Английский

---

Improved transition metal photosensitizers to drive advances in photocatalysis

Chemical Science, Journal Year: 2023, Volume and Issue: 15(1), P. 77 - 94

Published: Nov. 24, 2023

To function effectively in a photocatalytic application, photosensitizer's light absorption, excited-state lifetime, and redox potentials, both the ground state excited state, are critically important. The absorption profile is particularly relevant to applications involving solar harvesting, whereas potentials lifetimes determine thermodynamics, kinetics, quantum yields of photoinduced processes. This perspective article focuses on synthetic inorganic organometallic approaches optimize these three characteristics transition-metal based photosensitizers. We include our own work areas, which has focused extensively exceptionally strong cyclometalated iridium photoreductants that enable challenging reductive photoredox transformations organic substrates, more recent led improved harvesting charge-transfer copper(i) chromophores, an emerging class earth-abundant compounds solar-energy applications. also highlight many other complementary strategies for optimizing parameters representative examples from literature. It remains significant challenge simultaneously all at once, since improvements one often come detriment others. These inherent trade-offs obviate or circumvent them discussed throughout.

Language: Английский

---

Making Mo(0) a Competitive Alternative to Ir(III) in Phosphors and Photocatalysts

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 23, 2025

Iridium is used in commercial light-emitting devices and photocatalysis but among the rarest stable chemical elements. Therefore, replacing iridium(III) photoactive molecular complexes with abundant metals of great interest. First-row transition generally tend to yield poorer luminescence behavior, it remains difficult obtain excited states redox properties that exceed those noble-metal-based photocatalysts. Here, we overcome these challenges a nonprecious second-row metal. Tailored coordination spheres for molybdenum(0) lead photoluminescence quantum yields rival photochemical reduction reactions not normally achievable become possible. These developments open new perspectives noble lighting applications Earth-abundant advancing metal-based beyond current limits.

Language: Английский

---

The Nephelauxetic Effect Becomes an Important Design Factor for Photoactive First‐Row Transition Metal Complexes

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(30)

Published: April 14, 2023

Abstract The expansion of d‐orbitals as a result metal‐ligand bond covalence, the so‐called nephelauxetic effect, is well‐established concept coordination chemistry, yet its importance for design new photoactive complexes based on first‐row transition metals only beginning to be recognized. Until recently, much focus has been optimizing ligand field strength, geometries, and molecular rigidity, but now it becomes evident that effect can game changer regarding photophysical properties 3d metal in solution at room temperature. In Cr III Mn IV with d 3 valence electron configuration, was exploited shift well‐known ruby‐like red luminescence near‐infrared spectral region. Fe II Co low‐spin 6 charge‐transfer excited states were stabilized respect detrimental metal‐centered states, improve their enhance application potential. isoelectronic (3d ) isocyanide 0 I , likely play well, enabling other favorable photoreactivity. This minireview illustrates broad applicability tailoring photochemical compounds made from abundant metals.

Language: Английский

---

The great strides of iron photosensitizers for contemporary organic photoredox catalysis: On our way to the holy grail?

Coordination Chemistry Reviews, Journal Year: 2023, Volume and Issue: 500, P. 215522 - 215522

Published: Nov. 9, 2023

Language: Английский

---

Factors that Impact Photochemical Cage Escape Yields

Chemical Reviews, Journal Year: 2024, Volume and Issue: 124(11), P. 7379 - 7464

Published: May 14, 2024

The utilization of visible light to mediate chemical reactions in fluid solutions has applications that range from solar fuel production medicine and organic synthesis. These are typically initiated by electron transfer between a photoexcited dye molecule (a photosensitizer) redox-active quencher yield radical pairs intimately associated within solvent cage. Many these radicals undergo rapid thermodynamically favored "geminate" recombination do not diffuse out the cage surrounds them. Those escape useful reagents may subsequent important above-mentioned applications. process factors determine yields remain poorly understood despite decades research motivated their practical fundamental importance. Herein, state-of-the-art on light-induced appeared since seminal 1972 review J. P. Lorand entitled "The Cage Effect" is reviewed. This also provides some background for those new field discusses both homolytic bond photodissociation bimolecular induced reactions. concludes with key goals directions future promise elevate this very vibrant even greater heights.

Language: Английский

---

Boosted Second Harmonic Generation of a Chiral Hybrid Lead Halide Resonant to Charge Transfer Exciton from Metal Halide Octahedra to Ligand

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(19)

Published: March 12, 2024

Abstract Chiral hybrid organic–inorganic metal halides (HOMHs) offer an ideal platform for the advancement of second‐order nonlinear optical (NLO) materials owing to their inherent noncentrosymmetric structures. The enhancement nonlinearity chiral HOMHs could be achieved by matching free exciton and/or self‐trapped energy levels with desired NLO frequencies. However, current scarcity resonance modes and low ratio hamper further improvements performance. Herein, we propose a new resonant channel charge transfer (CT) excited states from halide polyhedra organic ligand boost HOMHs. model lead (C 7 H 10 N)PbBr 3 N=1‐ethylpyridinium) exhibits drastically enhanced second harmonic generation in deep CT energy, intensity up 111.0 times that KDP 10.9 urea. effective coefficient has been determined as high ~40.2 pm V −1 , balanced large polarization laser damage threshold. This work highlights contribution ligands construction enhancing coefficients halides, thus provides guidelines designing advanced photonic applications.

Language: Английский

---