1
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Maafi M. On photokinetics under polychromatic light. Front Chem 2024; 12:1367276. [PMID: 38711947 PMCID: PMC11070525 DOI: 10.3389/fchem.2024.1367276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 03/12/2024] [Indexed: 05/08/2024] Open
Abstract
Since the dawn of photochemistry 150 years ago, photoreactions have been conducted under polychromatic light. However, despite the pivotal role that photokinetics should naturally play for such reactive photosystems, the literature lacks a comprehensive description of that area. Indeed, one fails to identify explicit model integrated rate laws for these reactions, a characteristic type for their kinetic behavior, or their kinetic order. In addition, there is no consensus in the community on standardized investigative tools to evaluate the reactivity of these photosystems, nor are there venues for the discussion of such photokinetic issues. The present work is a contribution addressing some of these knowledge gaps. It proposes an unprecedented general formula capable of mapping out the kinetic traces of photoreactions under polychromatic light irradiation. This article quantitatively discusses several reaction situations, including the effects of initial reactant concentration and the presence of spectator molecules. It also develops a methodology for standardizing actinometers and defines and describes both the spectral range of highest reactivity and the photonic yield. The validity of the model equation has been proven by comparing its results to both theoretical counterparts and those generated by fourth-order Runge-Kutta numerical calculations. For the first time, a confirmation of the Φ -order character of the kinetics under polychromatic light was established.
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Affiliation(s)
- Mounir Maafi
- Leicester School of Pharmacy, De Montfort University, Leicester, United Kingdom
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2
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Bargstedt J, Reinschmidt M, Tydecks L, Kolmar T, Hendrich CM, Jäschke A. Photochromic Nucleosides and Oligonucleotides. Angew Chem Int Ed Engl 2024; 63:e202310797. [PMID: 37966433 DOI: 10.1002/anie.202310797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 11/14/2023] [Accepted: 11/15/2023] [Indexed: 11/16/2023]
Abstract
Photochromism is a reversible phenomenon wherein a material undergoes a change in color upon exposure to light. In organic photochromes, this effect often results from light-induced isomerization reactions, leading to alterations in either the spatial orientation or electronic properties of the photochrome. The incorporation of photochromic moieties into biomolecules, such as proteins or nucleic acids, has become a prevalent approach to render these biomolecules responsive to light stimuli. Utilizing light as a trigger for the manipulation of biomolecular structure and function offers numerous advantages compared to other stimuli, such as chemical or electrical treatments, due to its non-invasive nature. Consequently, light proves particularly advantageous in cellular and tissue applications. In this review, we emphasize recent advancements in the field of photochromic nucleosides and oligonucleotides. We provide an overview of the design principles of different classes of photochromes, synthetic strategies, critical analytical challenges, as well as structure-property relationships. The applications of photochromic nucleic acid derivatives encompass diverse domains, ranging from the precise photoregulation of gene expression to the controlled modulation of the three-dimensional structures of oligonucleotides and the development of DNA-based fluorescence modulators. Moreover, we present a future perspective on potential modifications and applications.
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Affiliation(s)
- Jörn Bargstedt
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, 69120, Heidelberg, Germany
| | - Martin Reinschmidt
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, 69120, Heidelberg, Germany
| | - Leon Tydecks
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, 69120, Heidelberg, Germany
| | - Theresa Kolmar
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, 69120, Heidelberg, Germany
| | - Christoph M Hendrich
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, 69120, Heidelberg, Germany
| | - Andres Jäschke
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, 69120, Heidelberg, Germany
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3
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Moirangthem R, Gamage MN, Rokita SE. Dynamic accumulation of cyclobutane pyrimidine dimers and its response to changes in DNA conformation. Nucleic Acids Res 2023; 51:5341-5350. [PMID: 37207339 PMCID: PMC10287945 DOI: 10.1093/nar/gkad434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/19/2023] [Accepted: 05/09/2023] [Indexed: 05/21/2023] Open
Abstract
Photochemical dimerization of adjacent pyrimidines is fundamental to the creation of mutagenic hotspots caused by ultraviolet light. Distribution of the resulting lesions (cyclobutane pyrimidine dimers, CPDs) is already known to be highly variable in cells, and in vitro models have implicated DNA conformation as a major basis for this observation. Past efforts have primarily focused on mechanisms that influence CPD formation and have rarely considered contributions of CPD reversion. However, reversion is competitive under the standard conditions of 254 nm irradiation as illustrated in this report based on the dynamic response of CPDs to changes in DNA conformation. A periodic profile of CPDs was recreated in DNA held in a bent conformation by λ repressor. After linearization of this DNA, the CPD profile relaxed to its characteristic uniform distribution over a similar time of irradiation to that required to generate the initial profile. Similarly, when a T tract was released from a bent conformation, its CPD profile converted under further irradiation to that consistent with a linear T tract. This interconversion of CPDs indicates that both its formation and reversion exert control on CPD populations long before photo-steady-state conditions are achieved and suggests that the dominant sites of CPDs will evolve as DNA conformation changes in response to natural cellular processes.
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Affiliation(s)
- Ravina Moirangthem
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street,Baltimore, MD21218, USA
| | - Manusha N Gamage
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street,Baltimore, MD21218, USA
| | - Steven E Rokita
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street,Baltimore, MD21218, USA
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4
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West CP, Morales AC, Ryan J, Misovich MV, Hettiyadura APS, Rivera-Adorno F, Tomlin JM, Darmody A, Linn BN, Lin P, Laskin A. Molecular investigation of the multi-phase photochemistry of Fe(III)-citrate in aqueous solution. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2023; 25:190-213. [PMID: 35634912 DOI: 10.1039/d1em00503k] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Iron (Fe) is ubiquitous in nature and found as FeII or FeIII in minerals or as dissolved ions Fe2+ or Fe3+ in aqueous systems. The interactions of soluble Fe have important implications for fresh water and marine biogeochemical cycles, which have impacts on global terrestrial and atmospheric environments. Upon dissolution of FeIII into natural aquatic systems, organic carboxylic acids efficiently chelate FeIII to form [FeIII-carboxylate]2+ complexes that undergo a wide range of photochemistry-induced radical reactions. The chemical composition and photochemical transformations of these mixtures are largely unknown, making it challenging to estimate their environmental impact. To investigate the photochemical process of FeIII-carboxylates at the molecular level, we conduct a comprehensive experimental study employing UV-visible spectroscopy, liquid chromatography coupled to photodiode array and high-resolution mass spectrometry detection, and oil immersion flow microscopy. In this study, aqueous solutions of FeIII-citrate were photolyzed under 365 nm light in an experimental setup with an apparent quantum yield of (φ) ∼0.02, followed by chemical analyses of reacted mixtures withdrawn at increment time intervals of the experiment. The apparent photochemical reaction kinetics of Fe3+-citrates (aq) were expressed as two generalized consecutive reactions of with the experimental rate constants of j1 ∼ 0.12 min-1 and j2 ∼ 0.05 min-1, respectively. Molecular characterization results indicate that R and I consist of both water-soluble organic and Fe-organic species, while P compounds are a mixture of water-soluble and colloidal materials. The latter were identified as Fe-carbonaceous colloids formed at long photolysis times. The carbonaceous content of these colloids was identified as unsaturated organic species with low oxygen content and carbon with a reduced oxidation state, indicative of their plausible radical recombination mechanism under oxygen-deprived conditions typical for the extensively photolyzed mixtures. Based on the molecular characterization results, we discuss the comprehensive reaction mechanism of FeIII-citrate photochemistry and report on the formation of previously unexplored colloidal reaction products, which may contribute to atmospheric and terrestrial light-absorbing materials in aquatic environments.
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Affiliation(s)
- Christopher P West
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Ana C Morales
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Jackson Ryan
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Maria V Misovich
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | | | | | - Jay M Tomlin
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Andrew Darmody
- Department of Aeronautics and Aerospace Engineering, Purdue University, West Lafayette, IN, USA
| | - Brittany N Linn
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Peng Lin
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Alexander Laskin
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
- Department of Earth, Atmospheric & Planetary Sciences, Purdue University, West Lafayette, IN, USA
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5
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Riddell A, Kvist P, Bernin D. A 3D printed photoreactor for investigating variable reaction geometry, wavelength, and fluid flow. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:084103. [PMID: 36050099 DOI: 10.1063/5.0087107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 07/24/2022] [Indexed: 06/15/2023]
Abstract
Research in the field of photochemistry, including photocatalysis and photoelectrocatalysis, has been revitalized due to the potential that photochemical reactions show in the sustainable production of chemicals. Therefore, there is a need for flexible photoreactor equipment that allows for the evaluation of the geometry, light wavelength, and intensity of the vessel, along with the fluid flow in various photochemical reactions. Light emitting diodes (LEDs) have narrow emission spectra and can be either pulsed or run continuously; being flexible, they can be arranged to fit the dimensions of various types of the reactor vessel, depending on the application. This study presents a 3D printed photoreactor with the ability to adjust distances easily and switch between high-power LED light sources. The reactor design utilizes customized printed circuit boards to mount varying numbers and types of LEDs, which enables multiple wavelengths to be used simultaneously. These LED modules, comprised of heat sinks and cooling fans, fulfill the higher heat dissipation requirements of high-power LEDs. The flexibility of the reactor design is useful for optimizing the reaction geometry, flow conditions, wavelength, and intensity of photochemical reactions on a small scale. The estimates for incident light intensity under five possible reactor configurations using ferrioxalate actinometry are reported so that comparisons with other photoreactors can be made. The performance of the photoreactor for differing vessel sizes and distances, in both the flow and batch modes, is given for a photochemical reaction on 2-benzyloxyphenol-a model substance for lignin and applicable in the production of biobased chemicals.
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Affiliation(s)
- Alexander Riddell
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 41296 Gothenburg, Sweden
| | - Patric Kvist
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 41296 Gothenburg, Sweden
| | - Diana Bernin
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 41296 Gothenburg, Sweden
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6
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Maafi M, Al-Qarni MA. Photokinetics of Dacarbazine and Nifedipine under polychromatic light irradiation and their application as new reliable actinometers for the ultraviolet range. Sci Rep 2022; 12:7622. [PMID: 35538090 PMCID: PMC9090909 DOI: 10.1038/s41598-022-11570-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 04/19/2022] [Indexed: 11/30/2022] Open
Abstract
The photokinetic behaviour of drugs driven by polychromatic light is an area of pharmaceutics that has not received a lot of attention. Most often, such photokinetic data is treated by thermal kinetic models (i.e., the classical 0th-, 1st- or 2nd-order equations). Such models were not analytically derived from the rate-laws of the photodegradation reactions. Polychromatic light kinetic modelling is hence of importance, as a means to providing adequate toolkits and metrics. This paper aims at proposing two reliable drug-actinometers useful for polychromatic UVA range. The general actinometric methodology offered here is also useful for any drugs/materials obeying a primary photoprocess where both reactant and photoproduct absorb the incident light, of the \documentclass[12pt]{minimal}
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\begin{document}$$AB{(1\Phi )}_{{\varepsilon }_{B}\ne 0}$$\end{document}AB(1Φ)εB≠0 type. The present method has been consolidated by the η-order kinetics. This framework further demonstrated the lamp-specificity of actinometers. Overall, Dacarbazine and Nifedipine photodegradations obeyed η-order kinetics, and stand as effective actinometers that can be recommended for the ICH Q1b photostability testing.
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Affiliation(s)
- Mounir Maafi
- Leicester School of Pharmacy, De Montfort University, The Gateway, Leicester, LE1 9BH, UK.
| | - Mohammed Ahmed Al-Qarni
- Department of Pharmaceutical Chemistry, College of Pharmacy, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
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7
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Brevé TG, Filius M, Weerdenburg S, van der Griend SJ, Groeneveld TP, Denkova AG, Eelkema R. Light-Sensitive Phenacyl Crosslinked Dextran Hydrogels for Controlled Delivery. Chemistry 2022; 28:e202103523. [PMID: 34939694 PMCID: PMC9306828 DOI: 10.1002/chem.202103523] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Indexed: 11/16/2022]
Abstract
Stimuli-responsive soft materials enable controlled release of loaded drug molecules and biomolecules. Controlled release of potent chemotherapeutic or immunotherapeutic agents is crucial to reduce unwanted side effects. In an effort to develop controlled release strategies that can be triggered by using Cerenkov luminescence, we have developed polymer hydrogels that can release bovine serum albumin and immunoglobulin G by using light (254 nm-375 nm) as a trigger. We describe the synthesis and photochemical characterization of two light sensitive phenacyl bis-azide crosslinkers that are used to prepare transparent self-supporting hydrogel patches. One crosslinker was designed to optimize the overlap with the Cerenkov luminescence emission window, bearing an π-extended phenacyl core, resulting in a high quantum yield (14 %) of photocleavage when irradiated with 375 nm light. We used the extended phenacyl crosslinker for the preparation of protein-loaded dextran hydrogel patches, which showed efficient and selective dosed release of bovine serum albumin or immunoglobulin G after irradiation with 375 nm light. Cerenkov-triggered release is as yet inconclusive due to unexpected side-reactivity. Based on the high quantum yield, efficient release and large overlap with the Cerenkov window, we envision application of these photosensitive soft materials in radiation targeted drug release.
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Affiliation(s)
- Tobias G. Brevé
- Department of Chemical EngineeringDelft University of Technologyvan der Maasweg 92629 HZDelftThe Netherlands
| | - Mike Filius
- Department of BioNanoScienceDelft University of Technologyvan der Maasweg 92629 HZDelftThe Netherlands
| | - Sven Weerdenburg
- Department of Chemical EngineeringDelft University of Technologyvan der Maasweg 92629 HZDelftThe Netherlands
| | - Stefan J. van der Griend
- Department of Chemical EngineeringDelft University of Technologyvan der Maasweg 92629 HZDelftThe Netherlands
| | - Tim P. Groeneveld
- Department of Chemical EngineeringDelft University of Technologyvan der Maasweg 92629 HZDelftThe Netherlands
| | - Antonia G. Denkova
- Department of Radiation Science and TechnologyDelft University of TechnologyMekelweg 152629 JBDelftThe Netherlands
| | - Rienk Eelkema
- Department of Chemical EngineeringDelft University of Technologyvan der Maasweg 92629 HZDelftThe Netherlands
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8
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Tay NES, Lehnherr D, Rovis T. Photons or Electrons? A Critical Comparison of Electrochemistry and Photoredox Catalysis for Organic Synthesis. Chem Rev 2022; 122:2487-2649. [PMID: 34751568 PMCID: PMC10021920 DOI: 10.1021/acs.chemrev.1c00384] [Citation(s) in RCA: 143] [Impact Index Per Article: 71.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Redox processes are at the heart of synthetic methods that rely on either electrochemistry or photoredox catalysis, but how do electrochemistry and photoredox catalysis compare? Both approaches provide access to high energy intermediates (e.g., radicals) that enable bond formations not constrained by the rules of ionic or 2 electron (e) mechanisms. Instead, they enable 1e mechanisms capable of bypassing electronic or steric limitations and protecting group requirements, thus enabling synthetic chemists to disconnect molecules in new and different ways. However, while providing access to similar intermediates, electrochemistry and photoredox catalysis differ in several physical chemistry principles. Understanding those differences can be key to designing new transformations and forging new bond disconnections. This review aims to highlight these differences and similarities between electrochemistry and photoredox catalysis by comparing their underlying physical chemistry principles and describing their impact on electrochemical and photochemical methods.
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Affiliation(s)
- Nicholas E. S. Tay
- Department of Chemistry, Columbia University, New York, New York, 10027, United States
| | - Dan Lehnherr
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Tomislav Rovis
- Department of Chemistry, Columbia University, New York, New York, 10027, United States
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9
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Náfrádi M, Alapi T, Bencsik G, Janáky C. Impact of Reaction Parameters and Water Matrices on the Removal of Organic Pollutants by TiO 2/LED and ZnO/LED Heterogeneous Photocatalysis Using 365 and 398 nm Radiation. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 12:nano12010005. [PMID: 35009961 PMCID: PMC8746656 DOI: 10.3390/nano12010005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 05/05/2023]
Abstract
In this work, the application of high-power LED365nm and commercial, low-price LED398nm for heterogeneous photocatalysis with TiO2 and ZnO photocatalysts are studied and compared, focusing on the effect of light intensity, photon energy, quantum yield, electrical energy consumption, and effect of matrices and inorganic components on radical formation. Coumarin (COU) and its hydroxylated product (7-HC) were used to investigate operating parameters on the •OH formation rate. In addition to COU, two neonicotinoids, imidacloprid and thiacloprid, were also used to study the effect of various LEDs, matrices, and inorganic ions. The transformation of COU was slower for LED398nm than for LED365nm, but r07-HC/r0COU ratio was significantly higher for LED398nm. The COU mineralization rate was the same for both photocatalysts using LED365nm, but a significant difference was observed using LED398nm. The impact of matrices and their main inorganic components Cl- and HCO3- were significantly different for ZnO and TiO2. The negative effect of HCO3- was evident, however, in the case of high-power LED365nm and TiO2, and the formation of CO3•- almost doubled the r07-HC and contributes to the conversion of neonicotinoids by altering the product distribution and mineralization rate.
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Affiliation(s)
- Máté Náfrádi
- Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary;
| | - Tünde Alapi
- Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary;
- Correspondence:
| | - Gábor Bencsik
- Department of Physical Chemistry and Materials Science, University of Szeged, Rerrich Béla tér 1, H-6720 Szeged, Hungary; (G.B.); (C.J.)
| | - Csaba Janáky
- Department of Physical Chemistry and Materials Science, University of Szeged, Rerrich Béla tér 1, H-6720 Szeged, Hungary; (G.B.); (C.J.)
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10
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A kinetic study of the photooxidation of water by aqueous cerium(IV) in sulfuric acid using a diode array spectrophotometer. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2020.113110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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11
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Levin N, Marcolongo JP, Cadranel A, Slep LD. Time-Resolved Exploration of a photoCORM {Ru(bpy)} Model Compound. Inorg Chem 2020; 59:12075-12085. [DOI: 10.1021/acs.inorgchem.0c01025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Natalia Levin
- Facultad de Ciencias Exactas y Naturales, Departamento de Quı́mica Inorgánica, Analı́tica y Quı́mica Fı́sica, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
- Instituto de Quı́mica-Fı́sica de Materiales, Medio Ambiente y Energı́a, CONICET, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
| | - Juan Pablo Marcolongo
- Facultad de Ciencias Exactas y Naturales, Departamento de Quı́mica Inorgánica, Analı́tica y Quı́mica Fı́sica, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
- Instituto de Quı́mica-Fı́sica de Materiales, Medio Ambiente y Energı́a, CONICET, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
| | - Alejandro Cadranel
- Facultad de Ciencias Exactas y Naturales, Departamento de Quı́mica Inorgánica, Analı́tica y Quı́mica Fı́sica, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
- Instituto de Quı́mica-Fı́sica de Materiales, Medio Ambiente y Energı́a, CONICET, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany
| | - Leonardo Daniel Slep
- Facultad de Ciencias Exactas y Naturales, Departamento de Quı́mica Inorgánica, Analı́tica y Quı́mica Fı́sica, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
- Instituto de Quı́mica-Fı́sica de Materiales, Medio Ambiente y Energı́a, CONICET, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
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13
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Some physical parameters influencing the comprehensive evaluation of kinetic data in photochemical reactions and its application in the periodate-chemistry. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2019.112021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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14
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Betancourt-Buitrago LA, Ossa-Echeverry OE, Rodriguez-Vallejo JC, Barraza JM, Marriaga N, Machuca-Martínez F. Anoxic photocatalytic treatment of synthetic mining wastewater using TiO2and scavengers for complexed cyanide recovery. Photochem Photobiol Sci 2019; 18:853-862. [DOI: 10.1039/c8pp00281a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new pathway for selective photocatalytic reduction using a combination of scavengers for gold mining wastewater treatment.
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Affiliation(s)
| | | | | | - J. M. Barraza
- Universidad del Valle
- Chemical Engineering School
- Cali
- Colombia
| | - N. Marriaga
- Universidad del Valle
- Chemical Engineering School
- Cali
- Colombia
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15
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Wriedt B, Kowalczyk D, Ziegenbalg D. Experimental Determination of Photon Fluxes in Multilayer Capillary Photoreactors. CHEMPHOTOCHEM 2018. [DOI: 10.1002/cptc.201800106] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Benjamin Wriedt
- Ulm University Institute of Chemical Engineering Albert-Einstein-Allee 11 89081 Ulm Germany
| | - Daniel Kowalczyk
- Ulm University Institute of Chemical Engineering Albert-Einstein-Allee 11 89081 Ulm Germany
| | - Dirk Ziegenbalg
- Ulm University Institute of Chemical Engineering Albert-Einstein-Allee 11 89081 Ulm Germany
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16
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17
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Granados-Oliveros G, Torres E, Zambrano M, Nieto-Camacho A, Gómez-Vidales V. Formation of hydroxyl radicals by α-Fe2O3 microcrystals and its role in photodegradation of 2,4-dinitrophenol and lipid peroxidation. RESEARCH ON CHEMICAL INTERMEDIATES 2018. [DOI: 10.1007/s11164-018-3315-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Stadler E, Eibel A, Fast D, Freißmuth H, Holly C, Wiech M, Moszner N, Gescheidt G. A versatile method for the determination of photochemical quantum yieldsviaonline UV-Vis spectroscopy. Photochem Photobiol Sci 2018; 17:660-669. [DOI: 10.1039/c7pp00401j] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
On-line UV-Vis monitoring of photochemical reactions driven by LEDs allows the straightforward determination of quantum yields.
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Affiliation(s)
- Eduard Stadler
- Institute of Physical and Theoretical Chemistry
- NAWI Graz
- Graz University of Technology
- 8010 Graz
- Austria
| | - Anna Eibel
- Institute of Physical and Theoretical Chemistry
- NAWI Graz
- Graz University of Technology
- 8010 Graz
- Austria
| | - David Fast
- Institute of Physical and Theoretical Chemistry
- NAWI Graz
- Graz University of Technology
- 8010 Graz
- Austria
| | - Hilde Freißmuth
- Institute of Physical and Theoretical Chemistry
- NAWI Graz
- Graz University of Technology
- 8010 Graz
- Austria
| | - Christian Holly
- Institute of Physical and Theoretical Chemistry
- NAWI Graz
- Graz University of Technology
- 8010 Graz
- Austria
| | - Mathias Wiech
- Institute of Physical and Theoretical Chemistry
- NAWI Graz
- Graz University of Technology
- 8010 Graz
- Austria
| | | | - Georg Gescheidt
- Institute of Physical and Theoretical Chemistry
- NAWI Graz
- Graz University of Technology
- 8010 Graz
- Austria
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19
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Levin N, Perdoménico J, Bill E, Weyhermüller T, Slep LD. Pushing the photodelivery of nitric oxide to the visible: are {FeNO} 7 complexes good candidates? Dalton Trans 2017; 46:16058-16064. [PMID: 29119166 DOI: 10.1039/c7dt03142d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Photodelivery of NO requires stable compounds which can be made reactive by irradiation with (visible) light. Traditional {MNO}6 complexes require a substantial ligand design to shift their absorption spectra to the appropriate region of the electromagnetic spectrum. [Fe((CH2Py2)2Me[9]aneN3)(NO)](BF4)2 is a new {FeNO}7 octahedral coordination compound, which is thermally and air-stable in solution. Illumination with a 450 nm light source induces significant photodetachment of the coordinated NO (ϕNO = 0.52 mol einstein-1), suggesting that {FeNO}7 compounds can be in fact suitable compounds for therapeutic NO-photorelease.
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Affiliation(s)
- Natalia Levin
- Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, and INQUIMAE, Universidad de Buenos Aires - CONICET, Pabellón 2, 3er piso, Ciudad Universitaria, C1428EHA, Ciudad Autónoma de Buenos Aires, Argentina.
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20
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Serna-Galvis EA, Ferraro F, Silva-Agredo J, Torres-Palma RA. Degradation of highly consumed fluoroquinolones, penicillins and cephalosporins in distilled water and simulated hospital wastewater by UV 254 and UV 254/persulfate processes. WATER RESEARCH 2017; 122:128-138. [PMID: 28599158 DOI: 10.1016/j.watres.2017.05.065] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 05/19/2017] [Accepted: 05/28/2017] [Indexed: 06/07/2023]
Abstract
In this work, three penicillins (ampicillin "AMP", oxacillin "OXA" and cloxacillin "CLO"), two cephalosporins (cephalexin "CPX" and cephadroxyl "CPD") and three fluoroquinolones (levofloxacin "LEV", norfloxacin "NOR" and ciprofloxacin "CIP") were initially treated by UV254 and persulfate activated by UV254 (UV/PS). Significant differences in degradation kinetics under UV254 irradiation were found. Photodegradation followed the order: OXA > CPX > CPD > CLO > CIP > NOR > AMP ≫ LEV. Then, in order to study the participation of direct photolysis and reactive oxygen species (ROS) in photodegradation a model antibiotic of each class (OXA, CPX and CIP) was considered. OXA and CPX were mainly degraded by direct photolysis, whereas the CIP removal involved ROS and photolysis. On the other hand, the persulfate addition (UV/PS process) improved the removals due to sulfate radical formation, especially, in the case of antibiotics with lower photodegradation levels (i.e. LEV, AMP and NOR). Computational calculations on the representative antibiotics were applied to determine the regions susceptible to electrophilic attacks by degrading agents. The functional groups of OXA and CPX followed the reactivity order: thioether ≫ β-lactam ring > benzene ring. For CIP, the piperazyl moiety presented higher reactivity than the quinolone ring. Also, the antimicrobial activity (AA) evolution during the treatments was tested. In the cases of CPX and CIP, both UV254 and UV/PS removed the AA; which were associated with structural changes in their reactive moieties: β-lactam ring and piperazyl ring, respectively. However, in the case of OXA only the UV/PS system decreased AA, which was attributed to transformations in its penicillin electron-rich nucleus (thioether + β-lactam). Finally, the applicability of UV254 and UV/PS was assessed using synthetic hospital wastewater (HWW). The processes comparison showed that for practical purposes, OXA and CIP in HWW should be treated by UV/PS, while CPX in HWW could be treated by both UV254 and UV/PS.
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Affiliation(s)
- Efraím A Serna-Galvis
- Grupo de Investigación en Remediación Ambiental y Biocatálisis (GIRAB), Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
| | - Franklin Ferraro
- Departamento de Ciencias Básicas, Universidad Católica Luis Amigó, Transversal 51A No. 67B-90, Medellín, Colombia
| | - Javier Silva-Agredo
- Grupo de Investigación en Remediación Ambiental y Biocatálisis (GIRAB), Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia
| | - Ricardo A Torres-Palma
- Grupo de Investigación en Remediación Ambiental y Biocatálisis (GIRAB), Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
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21
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Peralta Muniz Moreira RDF, Humeres E, Berger C, Isabel Fernández M, Santaballa JA, Canle M. Photolytic insertion of albumin on activated carbon modified with ozone. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2017; 174:261-268. [PMID: 28806682 DOI: 10.1016/j.jphotobiol.2017.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 06/25/2017] [Accepted: 08/01/2017] [Indexed: 06/07/2023]
Abstract
254nm photolyses of bovine serum albumin [BSA] in aqueous solutions, were carried out in the presence of activated carbons modified by reaction with ozone. The photolyses were monitored by fluorescence spectroscopy and UV spectrophotometry, and the products were characterized by elemental analysis, FTIR, TGA, total organic carbon analyses [TOC], and XPS. The ozonation reaction was carried out at room temperature with O3 under dry and wet conditions. The carbon characterization showed that the reaction increased the amount of epoxide and carbonyl groups on the carbon matrix. The activated carbon modified with dry O3 exhibited higher concentration of oxidized groups in its surface, smaller surface area and lower thermal stability. Characterization of the photolysis of ozonized carbons pointed to a small release of carbon organic groups during the reaction with elimination of epoxide groups and increase of carbonyl groups without change of thermal stability. Photolysis of BSA in aqueous solution occurred with fluorescence quenching due to changes of the local microenvironment and/or macromolecular conformational changes. Absorbance increase of the UV spectrum indicated a hyperchromic effect due to albumin structure modifications during photolysis. TGA analysis of the photolysed activated carbons in the presence of BSA suggested that ozonized carbon samples underwent insertion of BSA upon photolysis, in particular the sample ozonized under dry conditions. The changes observed for the FTIR and elemental analysis agreed with this conclusion, which was further supported by 13C SS-NMR, fluorescence emission and XPS.
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Affiliation(s)
| | - Eduardo Humeres
- Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil
| | - Carolina Berger
- Departamento de Engenharia Química e Engenharia de Alimentos, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil
| | - M Isabel Fernández
- Universidade da Coruña, Grupo Reactividade Química e Fotorreactividade, Departamento de Química, Facultade de Ciencias & CICA, E-15071 A Coruña, Spain
| | - J A Santaballa
- Universidade da Coruña, Grupo Reactividade Química e Fotorreactividade, Departamento de Química, Facultade de Ciencias & CICA, E-15071 A Coruña, Spain
| | - Moisés Canle
- Universidade da Coruña, Grupo Reactividade Química e Fotorreactividade, Departamento de Química, Facultade de Ciencias & CICA, E-15071 A Coruña, Spain.
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22
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Kiss V, Lehoczki G, Ősz K. Mathematical description of pH-stat kinetic traces measured during photochemical quinone decomposition. Photochem Photobiol Sci 2017; 16:519-526. [PMID: 27942682 DOI: 10.1039/c6pp00333h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Substituted 1,4-benzoquinone (QR) derivatives are photosensitive in aqueous solution and form hydroquinones (QR-H2) and hydroxy-quinones (QR-OH), two weak acids in their photoreaction. For this reason, the kinetics of the photoreaction can be conveniently followed by the pH-stat titration technique. The mathematical description of the kinetic traces measured provides the two main parameters of the photoreaction: the differential quantum yield of the reaction (Φ) and the ratio of the two photo-products, i.e. the fraction of QR that is converted to QR-OH (α). These values are described in this paper for 2,5-dichloro-1,4-benzoquinone at different pH values, together with the detailed mathematical evaluation of the application limits of the pH-stat method for such reactions.
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Affiliation(s)
- Virág Kiss
- Department of Physical Chemistry, University of Debrecen, H-4032 Debrecen, Egyetem tér 1., Hungary.
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23
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Marcolongo JP, Schmidt J, Levin N, Slep LD. A chemometric approach for determining the reaction quantum yields in consecutive photochemical processes. Phys Chem Chem Phys 2017; 19:21373-21381. [DOI: 10.1039/c7cp03619a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Chemometrics helps in determining the quantum yields of multistep photoreactions and allows the deconvolution of the spectra of the colored intermediates.
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Affiliation(s)
- Juan P. Marcolongo
- Departamento de Química Inorgánica
- Analítica y Química Física
- Facultad de Ciencias Exactas y Naturales
- and INQUIMAE
- Universidad de Buenos Aires – CONICET
| | - Juan Schmidt
- Departamento de Química Inorgánica
- Analítica y Química Física
- Facultad de Ciencias Exactas y Naturales
- and INQUIMAE
- Universidad de Buenos Aires – CONICET
| | - Natalia Levin
- Departamento de Química Inorgánica
- Analítica y Química Física
- Facultad de Ciencias Exactas y Naturales
- and INQUIMAE
- Universidad de Buenos Aires – CONICET
| | - Leonardo D. Slep
- Departamento de Química Inorgánica
- Analítica y Química Física
- Facultad de Ciencias Exactas y Naturales
- and INQUIMAE
- Universidad de Buenos Aires – CONICET
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24
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Pino-Chamorro JÁ, Ditrói T, Lente G, Fábián I. A detailed kinetic study of the direct photooxidation of 2,4,6-trichlorophenol. J Photochem Photobiol A Chem 2016. [DOI: 10.1016/j.jphotochem.2016.07.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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25
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Ditrói T, Kalmár J, Pino-Chamorro JA, Erdei Z, Lente G, Fábián I. Construction of a multipurpose photochemical reactor with on-line spectrophotometric detection. Photochem Photobiol Sci 2016; 15:589-94. [DOI: 10.1039/c5pp00407a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A versatile photoreactor was constructed from commercially available parts, which is capable of recording high quality kinetic traces in homogeneous and heterogeneous photoreactions and also easily adaptable to flow-through operation.
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Affiliation(s)
- Tamás Ditrói
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- H-4010 Hungary
| | - József Kalmár
- MTA-DE Homogeneous Catalysis and Reaction Mechanisms Research Group
- Debrecen
- H-4010 Hungary
| | | | - Zsolt Erdei
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- H-4010 Hungary
| | - Gábor Lente
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- H-4010 Hungary
| | - István Fábián
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- H-4010 Hungary
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26
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Cigáň M, Jakusová K, Gáplovský M, Filo J, Donovalová J, Gáplovský A. Isatin phenylhydrazones: anion enhanced photochromic behaviour. Photochem Photobiol Sci 2015; 14:2064-73. [PMID: 26412034 DOI: 10.1039/c5pp00275c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The photochemical properties of two basic easily synthesized isatin N(2)-phenylhydrazones were investigated. Contrary to the corresponding isatin N(2)-diphenylhydrazones, only Z-isomers were isolated from the reaction mixtures during the synthesis due to their stabilization by intramolecular hydrogen bonding. Although the presence of the C=N double bond creates conditions for the formation of a simple on-off photoswitch, the low photochemical quantum yield and particularly the low switching amplitude in absorbance hamper their photochromic applications. However, the addition of strongly basic anions to phenylhydrazone solutions leads to isatin NH group deprotonation and creates a new diazene T-type Vis-Vis photochromic system with sufficiently separated absorption maxima. Interestingly, although the thermally stable A-form is also photostable in ambient light, its irradiation with a stronger LED source leads to thermally unstable B-form formation which rapidly isomerizes back to the corresponding A-form. The process is reversible and switching cycles can be repeated in both directions. The important advantages of this two-component organic chromophore-inorganic anion photochromic system are its easy synthesis, easy handling due to its insensitivity to room light, easy further structural modification and reversibility. The corresponding photochemical quantum yield, however, remains relatively low (Φ ∼ 0.001). The theoretically calculated properties are in agreement with the obtained experimental results and support the proposed reaction mechanism.
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Affiliation(s)
- M Cigáň
- Faculty of Natural Sciences, Comenius University in Bratislava, Institute of Chemistry, Bratislava, Slovakia.
| | - K Jakusová
- Faculty of Natural Sciences, Comenius University in Bratislava, Institute of Chemistry, Bratislava, Slovakia.
| | - M Gáplovský
- Faculty of Pharmacy, Comenius University in Bratislava, Department of Pharmaceutical Chemistry, Bratislava, Slovakia
| | - J Filo
- Faculty of Natural Sciences, Comenius University in Bratislava, Institute of Chemistry, Bratislava, Slovakia.
| | - J Donovalová
- Faculty of Natural Sciences, Comenius University in Bratislava, Institute of Chemistry, Bratislava, Slovakia.
| | - A Gáplovský
- Faculty of Natural Sciences, Comenius University in Bratislava, Institute of Chemistry, Bratislava, Slovakia.
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27
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Cigáň M, Gáplovský M, Jakusová K, Donovalová J, Horváth M, Filo J, Gáplovský A. Isatin N2-diphenylhydrazones: new easily synthesized Vis-Vis molecular photoswitches. RSC Adv 2015. [DOI: 10.1039/c5ra06625e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
An easily synthesized new type of Vis-Vis molecular switches based on hydrazone CN bond photoisomerization and isatin NH group deprotonation.
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Affiliation(s)
- M. Cigáň
- Faculty of Natural Sciences
- Institute of Chemistry
- Comenius University
- SK-842 15 Bratislava
- Slovakia
| | - M. Gáplovský
- Faculty of Natural Sciences
- Institute of Chemistry
- Comenius University
- SK-842 15 Bratislava
- Slovakia
| | - K. Jakusová
- Faculty of Natural Sciences
- Institute of Chemistry
- Comenius University
- SK-842 15 Bratislava
- Slovakia
| | - J. Donovalová
- Faculty of Natural Sciences
- Institute of Chemistry
- Comenius University
- SK-842 15 Bratislava
- Slovakia
| | - M. Horváth
- Faculty of Natural Sciences
- Institute of Chemistry
- Comenius University
- SK-842 15 Bratislava
- Slovakia
| | - J. Filo
- Faculty of Natural Sciences
- Institute of Chemistry
- Comenius University
- SK-842 15 Bratislava
- Slovakia
| | - A. Gáplovský
- Faculty of Natural Sciences
- Institute of Chemistry
- Comenius University
- SK-842 15 Bratislava
- Slovakia
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28
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Word TA, Whittington CL, Karolak A, Kemp MT, Woodcock HL, van der Vaart A, Larsen RW. Photoacoustic calorimetry study of ligand photorelease from the Ru(II)bis(2,2′-bipyridine)(6,6′-dimethyl-2,2′-bipyridine) complex in aqueous solution. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2014.11.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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29
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Bogdándi V, Lente G, Fábián I. Kinetics of the oxidation of isoniazid with the hypochlorite ion. RSC Adv 2015. [DOI: 10.1039/c5ra13540k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Isoniazid is oxidized within 1–10 seconds by the hypochlorite ion in a process that is first order with respect to both reactants and shows somewhat complicated stoichiometry.
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Affiliation(s)
- Virág Bogdándi
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- Hungary
| | - Gábor Lente
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- Hungary
| | - István Fábián
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- Hungary
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30
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Mitra R, Pramanik AK, Samuelson AG. Seleno‐Nucleobases and Their Water‐Soluble Ruthenium–Arene Half‐Sandwich Complexes: Chemistry and Biological Activity. Eur J Inorg Chem 2014. [DOI: 10.1002/ejic.201402412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Raja Mitra
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India, http://ipc.iisc.ernet.in/~ashoka/
| | - Anup K. Pramanik
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India, http://ipc.iisc.ernet.in/~ashoka/
| | - Ashoka G. Samuelson
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India, http://ipc.iisc.ernet.in/~ashoka/
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31
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Dóka E, Lente G, Fábián I. Kinetics of the autoxidation of sulfur(IV) co-catalyzed by peroxodisulfate and silver(I) ions. Dalton Trans 2014; 43:9596-603. [PMID: 24827586 DOI: 10.1039/c4dt00900b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The kinetics and mechanism of the reaction between dissolved oxygen and sulfur(iv) was studied in aqueous acidic medium using co-catalysts peroxodisulfate and silver(i) ions. The presence of both catalysts was required to observe measurable rates in the studied process. The reaction rate was determined through following the UV-absorption of hydrated sulfur dioxide, and the trends were determined as a function of pH, reactant and catalyst concentrations. Individual kinetic curves under conditions where dissolved oxygen was the limiting reagent were close to zeroth-order. A chain mechanism with four chain carriers, sulfite, sulfate, peroxomonosulfate ion radical and silver(ii) ion, is proposed to interpret all the kinetic and stoichiometric findings, and an explicit formula was obtained for the rate law. The role of the co-catalysts is to produce chain carriers, whereas silver(i) and silver(ii) ions also participate in chain propagation steps. Further supporting evidence for the proposed mechanism was gained in laser flash photolysis studies, which showed that sulfate ion radical reacts quite rapidly with silver(i) ion.
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Affiliation(s)
- Eva Dóka
- University of Debrecen, Department of Inorganic and Analytical Chemistry, Debrecen 10, P.O.B. 21, H-4010, Hungary.
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32
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Józsa É, Purgel M, Bihari M, Fehér PP, Sustyák G, Várnagy B, Kiss V, Ladó E, Ősz K. Kinetic studies of hydroxyquinone formation from water soluble benzoquinones. NEW J CHEM 2014. [DOI: 10.1039/c3nj01274c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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33
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Aillet T, Loubiere K, Dechy-Cabaret O, Prat L. Accurate Measurement of the Photon Flux Received Inside Two Continuous Flow Microphotoreactors by Actinometry. INTERNATIONAL JOURNAL OF CHEMICAL REACTOR ENGINEERING 2014. [DOI: 10.1515/ijcre-2013-0121] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
In this study, the photon flux received in two continuous flow microphotoreactors was measured by actinometry (potassium ferrioxalate). The microphotoreactors had two different geometries and were irradiated by either a polychromatic or a monochromatic light source. A model considering the partial absorption of photons through the reactor depth and, if required, the polychromatic character of the light source and the dependence of the actinometer properties on the wavelength were formulated to describe the variation of the actinometer conversion with the irradiation time. The photon flux received in the microphotoreactors could be thus accurately calculated as a function of the emitted wavelength. The same methodology was then applied to measure the photon flux received in a batch immersion well photoreactor. The radiant power received in each photoreactor was compared to that emitted by the lamp and major differences were found, thus confirming the need for this kind of in situ measurement. Finally, some guidelines based on a knowledge of the photon flux were proposed to compare various photoreactors. They revealed in particular that the choice of the most efficient photoreactor depended on the criteria chosen to evaluate the performances (i.e. productivity, Space Time Yield).
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34
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Mitra R, Samuelson AG. Mitigating UVA light induced reactivity of 6-thioguanine through formation of a Ru(ii) half-sandwich complex. RSC Adv 2014. [DOI: 10.1039/c4ra02960g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Half-sandwich ruthenium complexes of 6-thioguanine.
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Affiliation(s)
- Raja Mitra
- Department of Inorganic and Physical Chemistry
- Indian Institute of Science
- Bangalore 560012, India
| | - Ashoka G. Samuelson
- Department of Inorganic and Physical Chemistry
- Indian Institute of Science
- Bangalore 560012, India
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35
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Kalmár J, Dóka É, Lente G, Fábián I. Aqueous photochemical reactions of chloride, bromide, and iodide ions in a diode-array spectrophotometer. Autoinhibition in the photolysis of iodide ions. Dalton Trans 2014; 43:4862-70. [DOI: 10.1039/c3dt53255k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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