Publications related to Diradical

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Diradicals have gained interest for their unique electronic properties and potential applications in organic electronics and semiconductors. However, precise manipulation of electronic states and achieving satisfactory device performance remain challenging. Herein, we report the synthesis and characterization of tetraphenylethylene‐bridged salts and their neutral diradical counterparts obtained via two‐electron reduction. With extended conjugation and electron‐withdrawing N‐heterocyclic carbene (NHC) backbo

Molecular triplet states can produce significant phosphorescence and act as a relay state for luminescence, such as in up-conversion processes. While this property makes triplet emitters interesting for organic light-emitting diodes (OLEDs), the study of their luminescence at the single-molecule level in high-resolution scanning tunneling microscopy (STM) is challenging. We investigate individual Pd-octaethylporphyrin (PdOEP) molecules decoupled from Ag(100) and Ag(111) by an ultrathin NaCl layer and observ

Stereoisomers of C 13 Cl 2 exhibiting helical orbitals around a ring of carbon atoms were synthesized by atom manipulation on NaCl surfaces. We resolved the enantiomeric geometries of the singlet states by atomic force microscopy and mapped their helical orbital densities by scanning tunnelling microscopy. A π-orbital basis of the helical, non-planar singlets that twists by 90° in one circulation is consistent with a half-Möbius topology. In such a topology, the π-orbital basis changes sign with respect to

UV-induced phosphorescence from the lowest triplet state T1 of tryptophan (Trp) residues is widely used to monitor the structural dynamics of host proteins on long time scales. Probing the intrinsic properties of this optically "dark" state requires studies of Trp isolated in the gas phase, which are challenging due to low sample concentrations and the need to monitor the triplet over extended time scales. We discovered that excitation of cold, protonated noncovalent TrpH+-(H2

A central challenge in water electrolysis lies with the oxygen evolution reaction (OER) where the formation of molecular oxygen (O₂) is hindered by the constraint of angular momentum conservation. While the reactants OH⁻ or H₂O are diamagnetic, the O₂ product has a paramagnetic triplet ground state, requiring a change in spin configuration when being formed. This constraint has prompted interest in spin‐selective catalysts as a means to facilitate OER. In this context, the roles of magnetism and chirality‐i

We report a combined experimental and theoretical investigation of the ultrafast internal conversion (IC) and intersystem crossing (ISC) dynamics of two thiopyridone isomers in solution. Our study used sulfur K-edge ultrafast transient x-ray absorption spectroscopy (XAS), in conjunction with electronic excited state surface hopping molecular dynamics and simulations of the excited state XAS, to investigate the impact of the functional group substitution pattern and solvent on the dynamics of IC and ISC. The

Molecular photo-switches have significant potential for use in smart materials that can be controlled by light. Photo-switches function due to lowering or complete removal of the barrier to switching in the excited state. This constraint on the ground and excited state potential energy surfaces means that relatively few photo-switching molecules are known, and fewer that only utilise visible photons. Here, we report the unanticipated visible-light photo switching behavior of a conformationally strained elec

The BDTMe molecule-based material is the first example of a thiazyl radical to exhibit metamagnetic behavior. Contrary to the common idea that metamagnetism occurs in low-dimensional systems, it is found that BDTMe magnetic topology consists of a complex 3 ...

Time-resolved photoelectron spectroscopy can obtain detailed information about the dynamics of a chemical process on the femtosecond timescale. The resulting signal from such detailed experiments is often difficult to analyze and therefore theoretical calc ...

By measuring the THz electron spin resonance (ESR) transmission spectra and high-field magnetization on the spin-gapped system CuTe2O5, we identified the singlet-triplet excitations in the dimerized non-magnetic ground state. The determined spin-gap value ...

We present a functional imaging method based on triplet state kinetics. The triplet state of many known fluorophores shows a triplet lifetime typically in the order of ~10e-6 – 10e-3 s, 3-6 orders of magnitude longer than the associated fluorescence singlet lifetime. As a consequence triplet state sensing is more exposed to the microenvironment of fluorophores and can be used as a functional molecular antenna. By means of a modulated excitation scheme of pulses with varying duty cycles, the triplet state po

We present a functional imaging method based on triplet state kinetics. The triplet state of many known fluorophores show a triplet lifetime typically in the order of ~10e-6 – 10e-3 s, 3-6 orders of magnitude longer than the associated fluorescence singlet lifetime. As a consequence triplet state sensing is more exposed to the microenvironment of fluorophores and can be used as a functional molecular antenna. Using an adaptive modulated excitation scheme, these long living triplet state dynamics are accessi

A novel imaging method employing the different kinetics of the energetic states of fluorescent markers is presented, where the contrast depends on the triplet kinetics. An attractive feature of triplet states is their long lifetime, rendering them highly sensitive to the immediate environment of their fluorescent host molecules. They typically have a lifetime of the order of ~10us to 10ms, which is 3-6 orders of magnitude longer than the lifetimes of fluorescent singlet states. The concept exploits characte

This work deals with the engineering of a new luminescent complex of lanthanide, able to be specifically grafted onto biological materials and to emit a characteristic light useful in quantifying the concentration of the target molecules. We have based our molecular design on TbL1, wich possesses a significant quantum yield in water pointing to an efficient intramolecular energy transfer. We have elaborated the synthesis of a ligand derived from L1 and named L3, by functionalizing one of the chromophoric gr

Photoluminescence of p-type modulation doped (Cd,Mn)Te quantum wells is studied with carrier density up to 5 X 10(11) cm(-2) at various spin splittings. This splitting can be made larger than the characteristic energies of the system thanks to the giant Zeeman effect. At small spin splitting and regardless of the carrier density, the photoluminescence exhibits a single line, which corresponds to the charged exciton in the singlet state. Above a certain spin splitting, the charged exciton is destabilized in

The isolation and characterization of Ln(NO3)3 complexes (Ln=La, Pr, Nd, Eu, Tb, Lu) with 2,3-benzo-1,4,7,13-tetraoxa-10-azacyclo-penta-decane (L1) and two of its N-substituted derivatives (L2, L3) are reported. Structural information in the solid state is derived from spectroscopic data (vibrational, absorption, reflectance and luminescence spectra). Both ligand- and metal-centered luminescence of solutions of the complexes in oxygen-free and anhydrous acetonitrile are investigated. Substitution of the N–p

Time-resolved fluorescence spectra for C60 mols. embedded in Ne and Ar matrixes and C70 in Ne matrixes were recorded using a synchroscan streak camera. In the case of C60, the decay times of the S1 state are identical for all fluorescence bands confirming that it is a state of mixed T1g, T2g, and Gg characters. Its lifetime is detd. by the intersystem crossing rate to the triplet manifold which increases in going from Ar to Ne matrixes. This is attributed to a change of the dominant symmetry character of S1

We report femtosecond pump and probe experiments in a semiconductor microcavity containing quantum wells. At high pump fields, the exciton-polariton Rabi doublet changes into a triplet structure. The triplet splitting increases as the square root of the input intensity. The transmitted probe intensity is modulated with the corresponding frequency Versus pump-probe delay. The experimental results are discussed in terms of Mollow spectra of a saturated transition of a two-level system.

Various aspects of the pigment class based on 1,4-diketo-3,6-diphenyl-pyrrolo(3,4-c)pyrrole (DPP) are investigated. The thesis consists of two parts: the first part, motivated by the degradation problems of DPP, focuses on the molecular photophysics of the DPP class of compounds. The second part, motivated by photovoltaic applications, focuses on the electrical and photovoltaic properties of solid state DPP. Investigation of the photoluminescence of the main commercial derivative, p-Cl DPP (PCD) showed, tha

The reaction of 4-methoxy-1,2,3,4-tetrahydroisoquinolines I (R = MeO, R1 = H; RR1 = OCH2O) with Li diisopropylamide affords dimerization products II. The intermediacy of orthoquinodimethanes and diradicals is assumed. [on SciFinder (R)]

Diradical

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Backbone Engineering of Carbon‐Centered NHC‐Derived Diradicals: From Electronic State Tuning to High‐Performance Organic Field‐Effect Transistors

Probing Up-Conversion Electroluminescence of Decoupled Porphyrin Molecules in a Plasmonic Nanocavity

A molecule with half-Möbius topology

Fate of the Triplet State of Tryptophan Isolated in the Gas Phase

Spin Matters: A Multidisciplinary Roadmap to Understanding Spin Effects in Oxygen Evolution Reaction during Water Electrolysis

Influence of substitution pattern on the dynamics of internal conversion and intersystem crossing in thiopyridone isomers

Visible Light Photo-switching in a Conformationally-strained Electron Acceptor via a Dual Singlet-triplet Mechanism

Revising the common understanding of metamagnetism in the molecule-based bisdithiazolyl BDTMe compound

Quantum dynamics study of the competing ultrafast intersystem crossing and internal conversion in the "channel 3" region of benzene

Singlet-Triplet Excitations and High-Field Magnetization in CuTe2O5

Triplet State Imaging

Triplet Imaging by Modulated Excitation

Triplet imaging contrast by modulated excitation

Complexes luminescents de lanthanides avec des dérivés du cyclène comme briques pour l'ingénierie de sondes analytiques biomédicales

Photoluminescence of p-doped quantum wells with strong spin splitting

Characterization and photophysical properties of lanthanide macrocyclic complexes derived from (2,1)

Picosecond studies of the intramolecular relaxation processes in isolated C60 and C70 molecules

Strongly driven semiconductor microcavities: From the polariton doublet to an AC Stark triplet

Photochemical and photophysical properties of diketopyrrolopyrrole organic pigments

The spontaneous cyclodimerization of 2,3-dihydroisoquinolines after base promoted elimination of methanol from 4-methoxy-1,2,3,4-tetrahydroisoquinolines