Decay dynamics of aromatic thione triplet states in fluid solution

1983 ◽  
Vol 61 (5) ◽  
pp. 894-900 ◽  
Author(s):  
A. Safarzadeh-Amiri ◽  
R. E. Verrall ◽  
R. P. Steer
Keyword(s):  
Room Temperature ◽  
Radiative Decay ◽  
Quantum Yields ◽  
Triplet States ◽  
Fluid Solution ◽  
Excitation Spectra ◽  
Decay Constants ◽  
Diffusion Controlled ◽  
Phosphorescence Emission ◽  
Group Rotation

Phosphorescence emission and excitation spectra, quantum yields, and lifetimes of several aromatic thiones have been measured in fluid solution at room temperature. Excitation to any of the excited electronic states accessible in the near-uv and visible regions of the spectrum results in population of the lowest triplet state with near unit quantum yield. Triplets of relatively inflexible thiones decay non-radiatively with rate constants of the order of 105 s−1 whereas thiones capable of higher amplitude flexion or group rotation exhibit non-radiative decay constants ≥ 107 s−1 at infinite dilution in aprotic solvents. Self-quenching occurs at diffusion-controlled rates.

scholarly journals Dual ligand-based fluorescence and phosphorescence emission at room temperature from platinum thioxanthonyl complexes

2015 ◽  
Vol 44 (9) ◽  
pp. 3974-3987 ◽  
Author(s):  
Fabian Geist ◽  
Andrej Jackel ◽  
Rainer F. Winter
Keyword(s):  
Room Temperature ◽  
Platinum Complexes ◽  
Quantum Yields ◽  
Fluid Solution ◽  
Phosphorescence Emission ◽  
Fluorescence And Phosphorescence

Platinum complexes with σ-bonded thioxanthonyl (Tx) ligands exhibit, on irradiation into the Tx π→π* band, dual Tx-based fluorescence and phosphorescence emission with phosphorescence quantum yields of up to 19% in fluid solution at room temperature.

scholarly journals Absorption and Emission Spectroscopic Investigation of the Thermal Dynamics of the Archaerhodopsin 3 Based Fluorescent Voltage Sensor Archon2

2020 ◽  
Vol 21 (18) ◽  
pp. 6576
Author(s):  
Alfons Penzkofer ◽  
Arita Silapetere ◽  
Peter Hegemann
Keyword(s):  
Schiff Base ◽  
Melting Temperature ◽  
Absorption Maximum ◽  
Room Temperature ◽  
Voltage Sensor ◽  
Quantum Yields ◽  
Excitation Spectra ◽  
Thermal Dynamics ◽  
Absorption And Emission ◽  
Refrigerator Temperature

Archon2 is a fluorescent voltage sensor derived from Archaerhodopsin 3 (Arch) of Halorubrum sodomense using robotic multidimensional directed evolution approach. Here we report absorption and emission spectroscopic studies of Archon2 in Tris buffer at pH 8. Absorption cross-section spectra, fluorescence quantum distributions, fluorescence quantum yields, and fluorescence excitation spectra were determined. The thermal stability of Archon2 was studied by long-time attenuation coefficient measurements at room temperature (21 ± 1 °C) and at refrigerator temperature (3 ± 1 °C). The apparent melting temperature was determined by stepwise sample heating up and cooling down (obtained apparent melting temperature: 63 ± 3 °C). In the protein melting process protonated retinal Schiff base (PRSB) with absorption maximum at 586 nm converted to de-protonated retinal Schiff base (RSB) with absorption maximum at 380 nm. Storage of Archon2 at room temperature and refrigerator temperature caused absorption coefficient decrease because of partial protein clustering to aggregates at condensation nuclei and sedimentation. At room temperature an onset of light scattering was observed after two days because of the beginning of protein unfolding. During the period of observation (18 days at 21 °C, 22 days at 3 °C) no change of retinal isomer composition was observed indicating a high potential energy barrier of S0 ground-state isomerization.

Luminescence studies of copper(I)-containing [2]pseudorotaxanes

2011 ◽  
Vol 89 (2) ◽  
pp. 98-103 ◽  
Author(s):  
Breeze N. Briggs ◽  
Fabien Durola ◽  
David R. McMillin ◽  
Jean-Pierre Sauvage
Keyword(s):  
Excited State ◽  
Visible Light ◽  
Ground State ◽  
Room Temperature ◽  
Molecular Machines ◽  
Quantum Yields ◽  
Stacking Interactions ◽  
Fluid Solution ◽  
The Core ◽  
Photoluminescence Studies

This report describes photoluminescence studies of copper-containing [2]pseudorotaxanes that mimic elements of functioning molecular machines. Excitation with visible light induces a formal oxidation of the metal center and simulates an actuation process. In all four [2]pseudorotaxanes studied, the ring ligand is the same, but the thread ligand is variable, namely 2,9-di(anisol-4-yl)-1,10-phenanthroline (dap), 6,6′-di(anisol-4-yl)-2,2′-bipyridine (o-dabipy), 5,5′-di(anisol-4-yl)-2,2′-bipyridine (m-dabipy), or 8,8′-di(anisol-4-yl)-3,3′-bi-isoquinoline (dabiiq). The absorbance bandshapes suggest that aryl substituents extending from the core ligands engage in stacking interactions and induce a partially flattened structure in the ground state. More severe flattening occurs in the excited state and precludes the observation of emission if inter-ligand steric forces do not limit the distortion. Thus, the [2]pseudorotaxanes containing dap or o-dabipy as the thread ligand exhibit uncorrected emission maxima at around 720 nm in room-temperature dichloromethane, while the less constrained analogues, containing dabiiq or m-dabipy, are not emissive in fluid solution and barely exhibit a signal in rigid media. In dichloromethane, the luminescence quantum yields of the dap- and o-dabipy-containing systems are 6 × 10−4 and 4 × 10−4, and the excited-state lifetimes are 98 ns and 90 ns, respectively.

Electronic spectroscopy of aromatic Schiff bases. V. Specific interactions involved between some typical benzylideneaniline molecules and small polar molecules

1982 ◽  
Vol 60 (18) ◽  
pp. 2332-2339 ◽  
Author(s):  
Michel Belletete ◽  
Gilles Durocher
Keyword(s):  
Radiative Decay ◽  
Polar Solvent ◽  
Electronic Spectroscopy ◽  
Quantum Yields ◽  
Polar Molecules ◽  
Strong Electron ◽  
Decay Constants ◽  
Fluorescence Quantum Yields ◽  
Polar Species ◽  
Solvent Molecules

Fluorescence quantum yields [Formula: see text], theoretical first-singlet radiative decay constants (kF(t)), and first-singlet non-radiative decay constants (knr) of some benzylideneanilines (BA) dissolved in methylcyclohexane have been obtained. High values of knr are interpreted by the twisting of the molecules around the azomethine bond (C=N) in the first singlet excited state. The absorption spectra of some BA's have also been obtained in methylcyclohexane with various added amounts of polar molecules. BA's with strong electron-donor and/or strong electron-acceptor substituents in the para positions give rise to the formation of ground state complexes with small polar molecules. The stoichiometry of the complex is one BA molecule for two polar solvent molecules; when ethanol is used as a polar solvent, it is further involved in hydrogen bonding formation. The fluorescence spectra of 4-dimethylaminobenzylidene-4′-nitroaniline have been obtained in methylcyclohexane with various added amounts of polar species. The results are interpreted by the formation of exciplexes with polar compound. The Lippert–Mataga theory and the more generalized Kawski theory failed to explain the solute-solvent interactions disussed in this paper.

Restriction of Access to Dark State: A New Mechanistic Model for Heteroatom-Containing AIE Systems

2019 ◽  
Author(s):  
Yujie Tu ◽  
Junkai Liu ◽  
Haoke Zhang ◽  
Qian Peng ◽  
Jacky W. Y. Lam ◽  
...  
Keyword(s):  
Excited States ◽  
Radiative Decay ◽  
Molecular Design ◽  
Mechanistic Model ◽  
Zinc Ion ◽  
Easy Access ◽  
Triplet States ◽  
Dark State ◽  
Ion Probe ◽  
Π State

Aggregation-induced emission (AIE) is an unusual photophysical phenomenon and provides an effective and advantageous strategy for the design of highly emissive materials in versatile applications such as sensing, imaging, and theragnosis. "Restriction of intramolecular motion" is the well-recognized working mechanism of AIE and have guided the molecular design of most AIE materials. However, it sometimes fails to be workable to some heteroatom-containing systems. Herein, in this work, we take more than one excited state into account and specify a mechanism –"restriction of access to dark state (RADS)" – to explain the AIE effect of heteroatom-containing molecules. An anthracene-based zinc ion probe named APA is chosen as the model compound, whose weak fluorescence in solution is ascribed to the easy access from the bright (π,π*) state to the closelying dark (n,π*) state caused by the strong vibronic coupling of the two excited states. By either metal complexation or aggregation, the dark state is less accessible due to the restriction of the molecular motion leading to the dark state and elevation of the dark state energy, thus the emission of the bright state is restored. RADS is found to be powerful in elucidating the photophysics of AIE materials with excited states which favor non-radiative decay, including overlap-forbidden states such as (n,π*) and CT states, spin-forbidden triplet states, which commonly exist in heteroatom-containing molecules.

scholarly journals Temperature-Dependent Stimulated Emission Cross-Section in Nd3+:YLF Crystal

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 431
Author(s):  
Giorgio Turri ◽  
Scott Webster ◽  
Michael Bass ◽  
Alessandra Toncelli
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Room Temperature ◽  
Radiative Decay ◽  
Emission Cross Section ◽  
Spectroscopic Properties ◽  
Stimulated Emission ◽  
Different Temperatures ◽  
Stimulated Emission Cross Section ◽  
Semi Empirical

Spectroscopic properties of neodymium-doped yttrium lithium fluoride were measured at different temperatures from 35 K to 350 K in specimens with 1 at% Nd3+ concentration. The absorption spectrum was measured at room temperature from 400 to 900 nm. The decay dynamics of the 4F3/2 multiplet was investigated by measuring the fluorescence lifetime as a function of the sample temperature, and the radiative decay time was derived by extrapolation to 0 K. The stimulated-emission cross-sections of the transitions from the 4F3/2 to the 4I9/2, 4I11/2, and 4I13/2 levels were obtained from the fluorescence spectrum measured at different temperatures, using the Aull–Jenssen technique. The results show consistency with most results previously published at room temperature, extending them over a broader range of temperatures. A semi-empirical formula for the magnitude of the stimulated-emission cross-section as a function of temperature in the 250 K to 350 K temperature range, is presented for the most intense transitions to the 4I11/2 and 4I13/2 levels.

Pure room temperature phosphorescence emission of organic host-guest doped system with quantum efficiency of 64%

2021 ◽  
Author(s):  
Xiaoqing Liu ◽  
Wenbo Dai ◽  
Qian Junjie ◽  
Yunxiang Lei ◽  
Miaochang Liu ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
Room Temperature ◽  
Room Temperature Phosphorescence ◽  
Halogen Atoms ◽  
System P ◽  
Phosphorescence Emission

A new doped system with pure phosphorescent emission is constructed using four 1-(4-(diphenylamino)phenyl)-2-phenylethan-1-one derivatives containing halogen atoms as the guests and benzophenone as the host. That is, the doped system...

Correction to “Ligand Initiated Self-Assembly of Pt and Ir Nanoparticles about Ru(II) Diimines in Room Temperature Fluid Solution”

2013 ◽  
Vol 117 (7) ◽  
pp. 3683-3683
Author(s):  
Parbatee Samaroo Jagassar ◽  
Anthony Perri ◽  
Guillermo Ibarrola ◽  
Harry D. Gafney
Keyword(s):  
Self Assembly ◽  
Room Temperature ◽  
Fluid Solution
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