Photophysical and structural characterization of a ruthenium complex–pyrene Coulombic dyad

Herein, we thoroughly investigate the (photo)physical properties and the geometry of the first reported Coulombic dyad, composed of dicationic tris(1,10-phenant

doi.org

Elucidating the Transition Kernel and Anharmonic Coupling in the Spin‐crossover Process of a [FeIII(qsal)2] CH3OSO3 Complex

Ultrafast broadband transient absorption spectroscopy and multireference excited-state nonadiabatic calculations in an open-shell Fe(III) complex unveil the rich electronic and vibrational dynamics d...

onlinelibrary.wiley.com

Stimuli-Responsive Thiele’s Hydrocarbon Derivatives: Potential Inversion, Strong Electronic Coupling, and Influence of Brønsted/Lewis Acids and Bases

Stimuli-responsive diradicaloid systems often display fascinating and tunable electrochemical, optical, and magnetic properties. Herein, we present the design and synthesis of a series of nitrogen-con...

pubs.acs.org

Beyond the Diffusion Limit: Preassociation Enhanced Photon Upconversion and Photocatalysis Sensitized by Iron Complex

Photoactive iron complexes present highly desirable and accessible alternatives to the well-known noble metal complex-based photocatalysts, thanks to iron’s high abundance, low toxicity, and minimal e...

pubs.acs.org

Expanding Thermodynamic and Kinetic Frontiers in Molecular Photocatalysis

Visible photons carry significantly more energy than the thermal energies typically used to overcome activation barriers in conventional chemistry. This thermodynamic advantage enables photochemical reactions that are inaccessible from electronic ground states. However, photochemistry also faces a kinetic challenge: excited states are inherently short-lived, necessitating rapid reactivity before their decay. In this Outlook, we explore the unique interplay of thermodynamics and kinetics in molecular photochemistry. We highlight current limits and knowledge gaps and propose directions for advancing the conceptual framework of photocatalysis. Topics include the design of photocatalysts with extreme redox potentials, the use of solvated electrons and visible-to-UV upconversion, and the potential to bypass Kasha’s rule for higher-energy photochemical processes. Our aim is to survey strategies for pushing the boundaries of photocatalysis and to inspire future conceptual innovation in the field.

pubs.acs.org

Synthesis and Excited-State Dynamics in Molecular Nanographene: Herzberg–Teller Vibronic Coupling and Energy Transfer to Porphyrins

Nanographenes (NGs) and graphene nanoribbons (GNRs) are molecular-level bridges to bulk-carbon materials. When synthesized with atomic precision via, for example, bottom-up strategies, a direct connection between the structure and properties is demonstrable. This is of key interest, especially considering practical applications. In the current work, we report the synthesis and comprehensive photophysical characterization of a full-benzenoid nanographene (NG-Br) and its covalent conjugate featuring a porphyrin (NG-(Zn)Por). Our synthetic approach relies on a cascade of Suzuki coupling, reduction, and Sandmeyer bromination reactions, starting from halogenated nitrobenzene derivatives. Knowing at which concentration aggregation occurs is important to study either monomers of NG-Br or its aggregates. In organic solvents, the association constant of NG-Br exceeds 1 × 106 M–1. Photophysical and theoretical analyses on the monomer revealed a subtle energy proximity between (S1)/(Lb) and (S2)/(La) that is the basis for strong vibronic coupling via the Herzberg–Teller mechanism, as well as (S1,1) and (S2,0) vibronic mixing. In NG-(Zn)Por, an ultrafast (S1–S1) energy transfer from NG to the porphyrin was observed. Our findings are essential for establishing an unambiguous structure–property relationship for NGs and 9-armchair GNRs, providing a blueprint for their use in optoelectronic devices ranging from single-electron transistors to OLEDs and organic solar cells.

pubs.acs.org

Enzyme-inspired single-atom photocatalysis for oxygen reduction to hydrogen peroxide

Nature Communications - Selective conversion of oxygen into hydrogen peroxide under light irradiation was achieved using enzyme-inspired carbon dots decorated with single copper ions. Time-resolved...

rdcu.be

Homomolecular Photon Upconversion in a Perylene-Decorated Iron(III) Complex

Classical upconversion employs sensitizers and annihilators as two distinct molecular species and is, therefore, classified as heteromolecular. Homomolecular upconversion, the unification of both role...

pubs.acs.org

Ultrafast Dissipation via Interligand Electron Transfer in {Ru(tpy)(bpy)} Chromophores

With the aim of studying interligand electron transfer (ILET) with different driving forces, [Ru(tpy)(R-bpy)(CN)]+ complexes with R-bpy = 4,4′-dimethylamino-2,2′-bipyridine (dMAb), 4,4′-dimethoxy-2,2′...

pubs.acs.org

Captivating bimolecular photoredox dynamics of a ligand-to-metal charge transfer complex

Transition metal complexes featuring ligand-to-metal charge transfer (LMCT) excited states have been identified as promising candidates for driving electron transfer processes. To obtain an efficient ...

pubs.rsc.org

Spin-State and Reorganization Energy Considerations for Metal-Centered Photoredox Catalysis

Transition-metal complexes featuring metal-centered excited states have recently emerged as mechanistically distinct platforms for selective photochemistry, including photoredox catalysis. Among these...

pubs.acs.org

https://pubs.acs.org/doi/10.1021/acscentsci.5c01040

t.co

t.co

Breaking Kasha’s Rule to Enable Higher Reactivity in Photoredox Catalysis

Nearly all photochemical transformations known to date follow Kasha’s rule, implying that reactions occur only from the lowest electronically excited state of a given spin multiplicity due to the fast...

bit.ly

Nature of Anti‐Dissipative High‐Energy Excited States in Quaterpyridine‐Bridged Ruthenium Complexes

Upon photoexcitation, meta-connected quaterpyridine-bridged Ru complexes undergo fast inter-ligand electron transfer like typical chromophores, but unusually slow intra-ligand electron transfer withi...

onlinelibrary.wiley.com

High-pressure pump–probe experiments reveal the mechanism of excited-state proton-coupled electron transfer and a shift from stepwise to concerted pathways

Nature Chemistry - Chemical energy conversion and storage rely on the selective movement of protons and electrons, thus understanding these processes is important for applications. Now experiments...

rdcu.be

Excited State Dynamics of Odd [n]Cumulenes: Chain Length and Conformational Effects

Over the past decades, carbon allotropes have been extensively studied and applied to various technological applications due to their unique electronic and optical properties. Contemporary research ha...

pubs.acs.org

A Near-Infrared-II Luminescent and Photoactive Vanadium(II) Complex with a 760 ns Excited State Lifetime

Ruthenium and iridium are key components in the most important applications of photoactive complexes, namely, light-emitting devices, photocatalysis, bioimaging, biosensing, and photodynamic therapy. ...

pubs.acs.org

Abundant Transition Metal Based Photocatalysts for Red Light‐Driven Photocatalysis

We discussed here the recent developments on the abundant transition metal based photocatalysts and their applications in red light-driven photocatalysis.

doi.org

Electronic Structure with Orca: Solvent Effects in the Calculation of IR Spectra

YouTube video by Prof Nicolas

youtu.be

Molecular Design Principles for Photoactive Transition Metal Complexes: A Guide for “Photo-Motivated” Chemists

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

pubs.acs.org

PCL — Open Positions

rtg2861-pcl.chm.tu-dresden.de