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Verma P. Decay-Associated Fluorescence for Boron Determination in Uranium-Based Nuclear Fuels. ACS OMEGA 2023; 8:47271-47276. [PMID: 38107959 PMCID: PMC10720028 DOI: 10.1021/acsomega.3c07535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/01/2023] [Accepted: 11/15/2023] [Indexed: 12/19/2023]
Abstract
Herein is reported a novel as well as simple, sensitive, and cost-effective method for determination of boron by time-resolved fluorescence spectrometry in uranium-based nuclear fuels. Boron is complexed with fluorescent ligand chromotropic acid, and the complex formed is a measure of boron. Since the steady-state fluorescence spectra of excess ligand and complex are overlapping, the developed method emphasizes the power of time resolution. The signatory fluorescence decay times of ligand and complex are employed to derive their decay-associated spectra (DAS) and, thereby, spectroscopically eliminate the high background of ligand fluorescence. The calibration plot has a wide linear dynamic range of 5-100 ppb with r2 better than 0.998. Precision is better than 5% at the 10 ppb level and 4% at the 50 ppb level (n = 9). The detection limit is 1.5 ppb, and recovery of spiked boron (25 ppb) from the uranium samples was better than 94%. The developed method was validated by analyzing U3O8-based ILCE Standards and applied to enriched uranium fuel samples. The main advantage of the developed method is a reduction in sample size requirement due to better sensitivity and selectivity. This in turn reduces the load of uranium recovery from analytical waste, especially in the case of enriched uranium samples. Additionally, it eliminates the need of organic solvents/medium.
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Affiliation(s)
- Poonam Verma
- Radioanalytical Chemistry
Division, Bhabha Atomic Research Centre, Mumbai 400085, India
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Kim SY, Yu JW, Choi S, Cho DW, Kim CH, Son HJ, Kang SO. Amplified Triplet Emission of Organic Periphery Groups by Exothermic Triplet-Triplet Energy Transfer from the 3MLCT State of an Ir(pmi)3 Core Complex to the 3LC State of Geometrically Confined Carbazole/Naphthyl Tethers. Inorg Chem 2023; 62:14228-14242. [PMID: 37612826 DOI: 10.1021/acs.inorgchem.3c01452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
To investigate the excited-state properties of metal-organic bichromophores, including energy transfer mechanisms, a series of new homoleptic N-heterocyclic carbene (NHC)-based iridium(III) complexes were prepared by incorporating a peripheral naphthalene (Np) (Ir(Nppmi)3: fac-/mer-Ir(1-Nppmi)3 and fac-/mer-Ir(2-Nppmi)3) or carbazole (Cz) (Ir(Czpmi)3: fac-/mer-Ir(o-Czpmi)3, fac-/mer-Ir(m-Czpmi)3, and fac-/mer-Ir(p-Czpmi)3) unit to the phenyl moiety of the phenylimidazole (pmi) ligand. Through a series of photophysical analyses and femtosecond time-resolved absorption (fs-TA) spectroscopy, it was discovered that the phosphorescence of the Ir core, (Ir(pmi)3), was considerably quenched, while intense phosphorescence peaks arising from the excited triplet Np (3Np*)/Cz (3Cz*) species were primarily observed at room temperature (r.t.) and low temperature. Such amplified phosphorescence of the tethered organic Np and Cz units originated from triplet-triplet energy transfer (TTET) from the high-lying metal-to-ligand charge transfer (3MLCT) state of the Ir(pmi)3 core to the ligand-centered triplet state (3LC) of the peripheral Np and Cz units. This result indicates that the exothermic intramolecular energy transfer (IET) in the excited triplet state realizes the efficient phosphorescent emission of geometrically confined organic tethers.
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Affiliation(s)
- So-Yoen Kim
- Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea
| | - Jeong-Wan Yu
- Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea
| | - Sunghan Choi
- Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea
| | - Dae Won Cho
- Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea
| | - Chul Hoon Kim
- Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea
| | - Ho-Jin Son
- Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea
| | - Sang Ook Kang
- Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea
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Jovaišaitė J, Baronas P, Jonusauskas G, Gudeika D, Gruodis A, Gražulevičius JV, Juršėnas S. TICT compounds by design: comparison of two naphthalimide-π-dimethylaniline conjugates of different lengths and ground state geometries. Phys Chem Chem Phys 2023; 25:2411-2419. [PMID: 36598166 DOI: 10.1039/d2cp04250a] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Two new twisted intramolecular charge transfer (TICT) donor-π-acceptor compounds were designed by combining a well-known electron acceptor naphthalimide unit with a classic electron donor dimethylaniline through two types of different rigid linkers. The combined steady-state and time-resolved spectroscopy of molecules in solvents of different polarities in comparison to solid-state solvation experiments of doped polymer matrixes of different polarities allowed distinguishing between solvation and conformation determined processes. The photophysical measurements revealed that non-polar solutions possess high fluorescence quantum yields of up to 70% which is a property of pre-twisted/planar molecules in the excited charge transfer (CT) states. The increase of polarity allows tuning the Stokes shift through all the visible wavelength range up to 8601 cm-1 which is accompanied by a three orders of magnitude drop of fluorescence quantum yields. This is a result of the emerged TICT states as dimethylaniline twists to a perpendicular position against the naphthalimide core. The TICT reaction of molecules enables an additional non-radiative excitation decay channel, which is not present if the twisting is forbidden in a rigid polymer matrix. Transient absorption spectroscopy was employed to visualize the excited state dynamics and to obtain the excited state reaction constants, revealing that TICT may occur from both the Franck-Condon region and the solvated pre-twisted/planar CT states. Both molecules undergo the same photophysical processes, however, a longer linker and thus a higher excited state dipole moment determines the faster excited state reactions.
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Affiliation(s)
- Justina Jovaišaitė
- Institute of Photonics and Nanotechnology, Vilnius University, Saulėtekio Ave. 3, LT-10257 Vilnius, Lithuania.
| | - Paulius Baronas
- Institute of Photonics and Nanotechnology, Vilnius University, Saulėtekio Ave. 3, LT-10257 Vilnius, Lithuania.
| | - Gediminas Jonusauskas
- Laboratoire Ondes et Matiére d'Aquitaine, Bordeaux University, UMR CNRS 5798, 351 cours de la Libération, 33405 Talence, France
| | - Dalius Gudeika
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilėnų rd. 19, LT-50254 Kaunas, Lithuania
| | - Alytis Gruodis
- Institute of Chemical Physics, Vilnius University, Saulėtekio Ave. 3, LT-10257 Vilnius, Lithuania
| | - Juozas V Gražulevičius
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilėnų rd. 19, LT-50254 Kaunas, Lithuania
| | - Saulius Juršėnas
- Institute of Photonics and Nanotechnology, Vilnius University, Saulėtekio Ave. 3, LT-10257 Vilnius, Lithuania.
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Knorr J, Sülzner N, Geissler B, Spies C, Grandjean A, Kutta RJ, Jung G, Nuernberger P. Ultrafast transient absorption and solvation of a super-photoacid in acetoneous environments. PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES : OFFICIAL JOURNAL OF THE EUROPEAN PHOTOCHEMISTRY ASSOCIATION AND THE EUROPEAN SOCIETY FOR PHOTOBIOLOGY 2022; 21:2179-2192. [PMID: 36178669 DOI: 10.1007/s43630-022-00287-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 08/08/2022] [Indexed: 12/13/2022]
Abstract
The phenomenon of photoacidity, i.e., an increase in acidity by several orders of magnitude upon electronic excitation, is frequently encountered in aromatic alcohols capable of transferring a proton to a suitable acceptor. A promising new class of neutral super-photoacids based on pyranine derivatives has been shown to exhibit pronounced solvatochromic effects. To disclose the underlying mechanisms contributing to excited-state proton transfer (ESPT) and the temporal characteristics of solvation and ESPT, we scrutinize the associated ultrafast dynamics of the strongest photoacid of this class, namely tris(1,1,1,3,3,3-hexafluoropropan-2-yl)8-hydroxypyrene-1,3,6-trisulfonate, in acetoneous environment, thereby finding experimental evidence for ESPT even under these adverse conditions for proton transfer. Juxtaposing results from time-correlated single-photon counting and femtosecond transient absorption measurements combined with a complete decomposition of all signal components, i.e., absorption of ground and excited states as well as stimulated emission, we disclose dynamics of solvation, rotational diffusion, and radiative relaxation processes in acetone and identify the relevant steps of ESPT along with the associated time scales.
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Affiliation(s)
- Johannes Knorr
- Physikalische Chemie II, Ruhr-Universität Bochum, 44780, Bochum, Germany.,Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Paul-Gordan-Straße 6, 91052, Erlangen, Germany
| | - Niklas Sülzner
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780, Bochum, Germany.,Physikalische Chemie II, Ruhr-Universität Bochum, 44780, Bochum, Germany
| | - Bastian Geissler
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstraße 31, 95053, Regensburg, Germany.,Physikalische Chemie II, Ruhr-Universität Bochum, 44780, Bochum, Germany
| | - Christian Spies
- Biophysikalische Chemie, Universität des Saarlandes, 66123, Saarbrücken, Germany.,Physikalische Chemie II, Ruhr-Universität Bochum, 44780, Bochum, Germany
| | - Alexander Grandjean
- Biophysikalische Chemie, Universität des Saarlandes, 66123, Saarbrücken, Germany
| | - Roger Jan Kutta
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstraße 31, 95053, Regensburg, Germany
| | - Gregor Jung
- Biophysikalische Chemie, Universität des Saarlandes, 66123, Saarbrücken, Germany
| | - Patrick Nuernberger
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstraße 31, 95053, Regensburg, Germany. .,Physikalische Chemie II, Ruhr-Universität Bochum, 44780, Bochum, Germany.
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Mascoli V, Gelzinis A, Chmeliov J, Valkunas L, Croce R. Light-harvesting complexes access analogue emissive states in different environments. Chem Sci 2020; 11:5697-5709. [PMID: 32874506 PMCID: PMC7441578 DOI: 10.1039/d0sc00781a] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 05/17/2020] [Indexed: 11/21/2022] Open
Abstract
The light-harvesting complexes (LHCs) of plants can regulate the level of excitation in the photosynthetic membrane under fluctuating light by switching between different functional states with distinct fluorescence properties. One of the most fascinating yet obscure aspects of this regulation is how the vast conformational landscape of LHCs is modulated in different environments. Indeed, while in isolated antennae the highly fluorescent light-harvesting conformation dominates, LHC aggregates display strong fluorescence quenching, representing therefore a model system for the process of energy dissipation developed by plants to avoid photodamage in high light. This marked difference between the isolated and oligomeric conditions has led to the widespread belief that aggregation is the trigger for the photoprotective state of LHCs. Here, a detailed analysis of time-resolved fluorescence experiments performed on aggregates of CP29 - a minor LHC of plants - provides new insights into the heterogeneity of emissive states of this antenna. A comparison with the data on isolated CP29 reveals that, though aggregation can stabilize short-lived conformations to a certain extent, the massive quenching upon protein clustering is mainly achieved by energetic connectivity between complexes that maintain the same long-lived and dissipative states accessed in the isolated form. Our results also explain the typical far-red enhancement in the emission of antenna oligomers in terms of a sub-population of long-lived redshifted complexes competing with quenched complexes in the energy trapping. Finally, the role of selected chlorophylls in shaping the conformational landscape of the antenna is also addressed by studying mutants lacking specific pigments.
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Affiliation(s)
- Vincenzo Mascoli
- Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics , Faculty of Sciences , Vrije Universiteit Amsterdam , De Boelelaan 1081 , 1081 HV Amsterdam , The Netherlands .
| | - Andrius Gelzinis
- Institute of Chemical Physics , Faculty of Physics , Vilnius University , Sauletekio Ave. 9 , LT-10222 Vilnius , Lithuania
- Department of Molecular Compound Physics , Center for Physical Sciences and Technology , Sauletekio Ave. 3 , LT-10257 Vilnius , Lithuania
| | - Jevgenij Chmeliov
- Institute of Chemical Physics , Faculty of Physics , Vilnius University , Sauletekio Ave. 9 , LT-10222 Vilnius , Lithuania
- Department of Molecular Compound Physics , Center for Physical Sciences and Technology , Sauletekio Ave. 3 , LT-10257 Vilnius , Lithuania
| | - Leonas Valkunas
- Institute of Chemical Physics , Faculty of Physics , Vilnius University , Sauletekio Ave. 9 , LT-10222 Vilnius , Lithuania
- Department of Molecular Compound Physics , Center for Physical Sciences and Technology , Sauletekio Ave. 3 , LT-10257 Vilnius , Lithuania
| | - Roberta Croce
- Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics , Faculty of Sciences , Vrije Universiteit Amsterdam , De Boelelaan 1081 , 1081 HV Amsterdam , The Netherlands .
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