Iron(III) Complexes with Luminescence Lifetimes of up to 100 ns to Enhance Upconversion and Photocatalysis

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

Published: Feb. 28, 2025

Iron is the most abundant transition metal element and would be ideal replacement for noble metals in many applications that rely on luminescent long-lived electronically excited states. We show efficient reversible energy transfer between doublet states of iron complexes triplet organic ligands improves storage by up to 350-fold. As a result, luminescence lifetimes 100 ns are achieved, upconversion from red blue light becomes 68 times more yield benchmark photoredox reactions significantly improved. These advances make coordination compounds promising candidates lighting, solar conversion photocatalysis.

Language: Английский

A Blessing and a Curse: Remote Ligand Functionalization Modulates ³MLCT Relaxation in Group 6 Tricarbonyl Complexes

Inorganic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 25, 2025

We recently reported a molecular design for carbonylpyridine molybdenum(0) complexes that unlocks long-lived luminescent and photoactive charge-transfer states. Here, we translate this strategy to chromium(0), tungsten(0) report three fully characterized tricarbonyl metal(0) featuring tripodal ligand with remote n-butyl substituent in the backbone. All show phosphorescence red near-infrared spectral region from metal-to-ligand excited Surprisingly, alkyl chain significantly affects state relaxation: lifetimes are shortened solution but extended solid by one order of magnitude compared complex methyl substituent. Temperature-dependent luminescence NMR spectroscopy combination quantum chemical calculations reveal reasons these disparate effects. The distorts metal coordination geometry. resulting structural flexibility flattens potential energy surfaces solution, which lowers barrier population distorted metal-centered states facilitates nonradiative relaxation. In state, rigidified separates neighboring molecules, reduces self-quenching. Our study sheds light on relationship between structure relaxation inform development based earth-abundant metals.

Language: Английский

Two Birds, One Stone: Microsecond Dark Excited-State Lifetime and Large Cage Escape Yield Afforded by an Iron–Anthracene Molecular Dyad

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

Published: Feb. 28, 2025

Iron photosensitizers represent a holy grail in photochemistry, but their widespread implementation is limited by short excited-state lifetimes and poor cage escape yields. Here, the introduction of an anthracene moiety appended to iron(III) complex allowed solve both limitations generate novel dyad exhibiting extraordinary lifetime 11.5 μs. The key achieving this remarkably long depopulation short-lived iron-centered emissive excited state populate dark triplet located on anthracene-like with spin-forbidden deactivation. Population only occurs ∼10% efficiency acetonitrile still allows expansion scope reactivity accessible iron-based photosensitizers, which now encompasses energy transfer 3O2. In addition, proof-of-principle investigation methyl viologen as electron acceptor, population drastic ten-fold increase yield from 4.5% for unsubstituted 42% molecular dyad. Hence, new provides complementary approach complexes based first-row transition metals alternatives well-established analogues precious metals. We believe that further spectroscopic investigations synthetic modifications acceptor linkage photosensitizer will be use these innovative dyads applications near future.

Language: Английский