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Tian R, Li K, Lin Y, Lu C, Duan X. Characterization Techniques of Polymer Aging: From Beginning to End. Chem Rev 2023; 123:3007-3088. [PMID: 36802560 DOI: 10.1021/acs.chemrev.2c00750] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Polymers have been widely applied in various fields in the daily routines and the manufacturing. Despite the awareness of the aggressive and inevitable aging for the polymers, it still remains a challenge to choose an appropriate characterization strategy for evaluating the aging behaviors. The difficulties lie in the fact that the polymer features from the different aging stages require different characterization methods. In this review, we present an overview of the characterization strategies preferable for the initial, accelerated, and late stages during polymer aging. The optimum strategies have been discussed to characterize the generation of radicals, variation of functional groups, substantial chain scission, formation of low-molecular products, and deterioration in the polymers' macro-performances. In view of the advantages and the limitations of these characterization techniques, their utilization in a strategic approach is considered. In addition, we highlight the structure-property relationship for the aged polymers and provide available guidance for lifetime prediction. This review could allow the readers to be knowledgeable of the features for the polymers in the different aging stages and provide access to choose the optimum characterization techniques. We believe that this review will attract the communities dedicated to materials science and chemistry.
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Affiliation(s)
- Rui Tian
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Kaitao Li
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yanjun Lin
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
- School of Chemical Engineering, Qinghai University, Xining 810016, China
| | - Chao Lu
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
| | - Xue Duan
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
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2
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Rouillon J, Arnoux C, Monnereau C. Determination of Photoinduced Radical Generation Quantum Efficiencies by Combining Chemical Actinometry and 19F NMR Spectroscopy. Anal Chem 2021; 93:2926-2932. [PMID: 33476133 DOI: 10.1021/acs.analchem.0c04540] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We introduce a general and relatively straightforward protocol aimed at determining the absolute photoinduced radical generation efficiency via NMR monitoring. This approach relies on the use of a radical scavenger probe that combines a nitroxide moiety that specifically reacts with radicals and a trifluoromethyl group used as a 19F NMR signaling unit. Using an LED source, whose fluence is precisely determined by a chemical actinometry procedure also described herein, the method is used to determine the radical photogeneration quantum yields of three well-known polymerization initiators: azobisisobutyronitrile (AIBN), 4,4'-bis(N,N-diethylamino)benzophenone (BDEBP, a derivative of Michler's ethyl ketone), and 2,4,6-trimethylbenzoyl diphenylphosphine oxide (MAPO). The overall good agreement with values previously reported in the literature proves the robustness of this new method. We then extended the study to the precise measurement of the quantum yield of free-radical photogeneration on a newly synthesized photoinitiator used for two-photon direct laser writing. This study highlights the potential of this methodology for the quantitative determination of photoinduced radical generation efficiency used in many fields of applications.
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Affiliation(s)
- Jean Rouillon
- Laboratoire de Chimie, Univ. Lyon, ENS Lyon, CNRS, Université Lyon 1, UMR 5182, 46 Allée d'Italie, 69364 Lyon, France
| | - Caroline Arnoux
- Laboratoire de Chimie, Univ. Lyon, ENS Lyon, CNRS, Université Lyon 1, UMR 5182, 46 Allée d'Italie, 69364 Lyon, France
| | - Cyrille Monnereau
- Laboratoire de Chimie, Univ. Lyon, ENS Lyon, CNRS, Université Lyon 1, UMR 5182, 46 Allée d'Italie, 69364 Lyon, France
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3
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Coiai S, Passaglia E, Cicogna F. Post-polymerization modification by nitroxide radical coupling. POLYM INT 2018. [DOI: 10.1002/pi.5664] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Serena Coiai
- Istituto di Chimica dei Composti OrganoMetallici (ICCOM); Consiglio Nazionale delle Ricerche; Pisa Italy
| | - Elisa Passaglia
- Istituto di Chimica dei Composti OrganoMetallici (ICCOM); Consiglio Nazionale delle Ricerche; Pisa Italy
| | - Francesca Cicogna
- Istituto di Chimica dei Composti OrganoMetallici (ICCOM); Consiglio Nazionale delle Ricerche; Pisa Italy
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4
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Bliumkin L, Dutta Majumdar R, Soong R, Adamo A, Abbatt JPD, Zhao R, Reiner E, Simpson AJ. Development of an in Situ NMR Photoreactor To Study Environmental Photochemistry. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:5506-5516. [PMID: 27172272 DOI: 10.1021/acs.est.6b00361] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Photochemistry is a key environmental process directly linked to the fate, source, and toxicity of pollutants in the environment. This study explores two approaches for integrating light sources with nuclear magnetic resonance (NMR) spectroscopy: sample irradiation using a "sunlight simulator" outside the magnet versus direct irradiation of the sample inside the magnet. To assess their applicability, the in situ NMR photoreactors were applied to a series of environmental systems: an atmospheric pollutant (p-nitrophenol), crude oil extracts, and groundwater. The study successfully illustrates that environmentally relevant aqueous photochemical processes can be monitored in situ and in real time using NMR spectroscopy. A range of intermediates and degradation products were identified and matched to the literature. Preliminary measurements of half-lives were also obtained from kinetic curves. The sunlight simulator was shown to be the most suitable model to explore environmental photolytic processes in situ. Other light sources with more intense UV output hold potential for evaluating UV as a remediation alternative in areas such as wastewater treatment plants or oil spills. Finally, the ability to analyze the photolytic fate of trace chemicals at natural abundance in groundwater, using a cryogenic probe, demonstrates the viability of NMR spectroscopy as a powerful and complementary technique for environmental applications in general.
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Affiliation(s)
- Liora Bliumkin
- Department of Chemistry, University of Toronto , Toronto, Ontario M5S 3H6, Canada
| | | | | | | | - Jonathan P D Abbatt
- Department of Chemistry, University of Toronto , Toronto, Ontario M5S 3H6, Canada
| | - Ran Zhao
- Department of Chemistry, University of Toronto , Toronto, Ontario M5S 3H6, Canada
| | - Eric Reiner
- Ontario Ministry of the Environment , Toronto, Ontario M9P 3 V6, Canada
| | - André J Simpson
- Department of Chemistry, University of Toronto , Toronto, Ontario M5S 3H6, Canada
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5
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Yan GP, Fairfull-Smith KE, Smith CD, Hanson GR, Bottle SE. Porphyrin containing isoindoline nitroxides as potential fluorescence sensors of free radicals. J PORPHYR PHTHALOCYA 2012. [DOI: 10.1142/s1088424611003203] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A series of new spin-labeled porphyrin containing isoindoline nitroxide moieties were synthesized and characterized as potential free radical fluorescence sensors. Fluorescence-suppression was observed in the free-base monoradical porphyrins, whilst the free-base biradical porphyrins exhibited highly suppressed fluorescence about three times greater than the monoradical porphyrins. The observed fluorescence-suppression was attributed to enhanced intersystem crossing resulting from electronexchange between the doublet nitroxide and the excited porphyrin fluorophore. Notably, fluorescencesuppression was not as strong in the related metalated porphyrins, possibly due to insufficient spin coupling between the nitroxide and the porphyrin. Continuous wave EPR spectroscopy of the diradical porphyrins in fluid solution suggests that the nitroxyl-nitroxyl interspin distance is long enough and tumbling is fast enough not to detect dipolar coupling.
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Affiliation(s)
- Guo-Ping Yan
- School of Material Science and Engineering, Wuhan Institute of Technology, Wuhan 430073, P.R. China
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Kathryn E. Fairfull-Smith
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Craig D. Smith
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Graeme R. Hanson
- Centre for Advanced Imaging, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Steven E. Bottle
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, Brisbane, QLD 4001, Australia
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6
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Morris JC, McMurtrie JC, Bottle SE, Fairfull-Smith KE. Generation of Profluorescent Isoindoline Nitroxides Using Click Chemistry. J Org Chem 2011; 76:4964-72. [DOI: 10.1021/jo200613r] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jason C. Morris
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology and ‡Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, Queensland 4001, Australia
| | - John C. McMurtrie
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology and ‡Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, Queensland 4001, Australia
| | - Steven E. Bottle
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology and ‡Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, Queensland 4001, Australia
| | - Kathryn E. Fairfull-Smith
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology and ‡Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, Queensland 4001, Australia
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7
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Investigation of polypropylene degradation during melt processing using a profluorescent nitroxide probe: A laboratory-scale study. Polym Degrad Stab 2011. [DOI: 10.1016/j.polymdegradstab.2011.01.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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8
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Blinco JP, Fairfull-Smith KE, Morrow BJ, Bottle SE. Profluorescent Nitroxides as Sensitive Probes of Oxidative Change and Free Radical Reactions. Aust J Chem 2011. [DOI: 10.1071/ch10442] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This paper presents a review on the use of tethered nitroxide–fluorophore molecules as probes of oxidative change and free radical generation and reaction. The proximity of the nitroxide free radical to the fluorophore suppresses the normal fluorescence emission process. Nitroxide free radical scavenging, metabolism or redox chemistry return the system to its natural fluorescent state and so these tethered nitroxide–fluorophore molecules are described as being profluorescent. A survey of profluorescent nitroxides found in the literature is provided as well as background on the mechanism of action and applications of these compounds as fluorometric probes within the fields of biological, materials and environmental sciences.
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Bueno C, Mikelsons L, Maretti L, Scaiano JC, Aspée A. Photophysical Properties of the Prefluorescent Nitroxide Probes QT and C343T. Photochem Photobiol 2008; 84:1535-42. [DOI: 10.1111/j.1751-1097.2008.00381.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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10
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Fairfull-Smith KE, Bottle SE. The Synthesis and Physical Properties of Novel Polyaromatic Profluorescent Isoindoline Nitroxide Probes. European J Org Chem 2008. [DOI: 10.1002/ejoc.200800597] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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11
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Fairfull-Smith KE, Blinco JP, Keddie DJ, George GA, Bottle SE. A Novel Profluorescent Dinitroxide for Imaging Polypropylene Degradation. Macromolecules 2008. [DOI: 10.1021/ma701944p] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kathryn E. Fairfull-Smith
- Australian Research Council Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia
| | - James P. Blinco
- Australian Research Council Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia
| | - Daniel J. Keddie
- Australian Research Council Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia
| | - Graeme A. George
- Australian Research Council Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia
| | - Steven E. Bottle
- Australian Research Council Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia
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12
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Aspée A, Aliaga C, Scaiano JC. Transient Enol Isomers of Dibenzoylmethane and Avobenzone as Efficient Hydrogen Donors toward a Nitroxide Pre-fluorescent Probe†. Photochem Photobiol 2007; 83:481-5. [PMID: 17094718 DOI: 10.1562/2006-08-01-ra-992] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dibenzoylmethane and avobenzone photochemistry involves the formation of transient enol isomers (Z and E). Conjugation of the OH group with the carbonyl group in these transient isomers reduces the OH bond energy. A fast reduction of the pre-fluorescent probe (C343T) was observed after addition to photolysed DBM samples in nonpolar solvents. This can be attributed to a hydrogen transfer reaction from the transient E accumulated. While no quenching for Z by TEMPO was detected in the laser flash photolysis timescale. Theoretical calculations of spin densities distribution of the radical formed from Z and E showed a more delocalized distribution that would indicate a low reactivity towards oxygen. Our results suggest that DBM and avobenzone can effectively behave as photoantioxidants or photoactivated antioxidants under conditions where its enol isomers can be accumulated.
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Affiliation(s)
- Alexis Aspée
- Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile.
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13
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Danko M, Chmela Š, Hrdlovič P. Synthesis, photochemical stability and photo-stabilizing efficiency of probes based on benzothioxanthene chromophore and Hindered Amine Stabilizer. Polym Degrad Stab 2006. [DOI: 10.1016/j.polymdegradstab.2005.07.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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14
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Dang YM, Guo XQ. New approach for the detection of peptide- and protein-based radicals using a pre-fluorescent probe. APPLIED SPECTROSCOPY 2006; 60:203-7. [PMID: 16542572 DOI: 10.1366/000370206776023269] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
A novel application for pre-fluorescent probes in the detection of peptide- and protein-based radicals is proposed. Pre-fluorescent probes combine a fluorescent moiety labeled with a paramagnetic nitroxide that acts as a fluorescence quencher. Trapping of a radical by the nitroxide group restores the fluorescence properties. The increase in fluorescence intensity with time reflects the formation and quenching of free radicals and can be employed for the quantitative evaluation of yields and kinetics. In this test system, the pre-fluorescent probe 4-(9-acridinecarbonate)-2,2,6,6-tetramethylpiperidinyl-1-oxyl radical (Ac-Tempo), in which an acridine moiety was labeled with 2,2,6,6-tetramethylpiperidinyl-1-oxy (Tempo), was employed to probe peptide- and protein-based radicals. Peptide-based radicals were generated through the reaction between horseradish peroxidase (HRP)/H(2)O(2) and a derivative of tyrosine. Protein-based radicals were generated through the reaction between myoglobin (Mb) and H(2)O(2). In both cases the Ac-Tempo was found, using a combination of high-performance liquid chromatography (HPLC) and mass spectrometry, to be converted into fluorescent acridine (Ac)-piperidine (4-(9-acridinecarbonate)-2,2,6,6-tetramethylpiperidine).
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Affiliation(s)
- Ya-Min Dang
- The MOE Key Laboratory of Analytical Science and the Key laboratory for Chemical Biology of Fujian Province, Department of Chemistry, Xiamen University, China
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15
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Micallef AS, Blinco JP, George GA, Reid DA, Rizzardo E, Thang SH, Bottle SE. The application of a novel profluorescent nitroxide to monitor thermo-oxidative degradation of polypropylene. Polym Degrad Stab 2005. [DOI: 10.1016/j.polymdegradstab.2005.01.030] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Keddie DJ, Johnson TE, Arnold DP, Bottle SE. Synthesis of profluorescent isoindoline nitroxides via palladium-catalysed Heck alkenylation. Org Biomol Chem 2005; 3:2593-8. [PMID: 15999192 DOI: 10.1039/b504354a] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of a new structural class of isoindoline nitroxides (aminoxyls), accessible via the palladium-catalysed Heck reaction, is presented. Reaction of the aryl bromoamine, 5-bromo-1,1,3,3-tetramethylisoindoline (4) or dibromoamine, 5,6-dibromo-1,1,3,3-tetramethylisoindoline (5) or the analogous bromonitroxides 6 and 7 with methyl acrylate gives the acrylate substituted tetramethylisoindoline amines 8 and 10 and nitroxides 12 and 14. Similarly, the reaction of the aryl bromides and dibromides 4-7 with methyl 4-vinylbenzoate gives the carboxystyryl substituted tetramethylisoindoline amines 9 and 11 and the analogous nitroxides 13 and 15. The carboxystyryl tetramethylisoindoline nitroxides demonstrate strongly suppressed fluorescence, which is revealed upon removal of the free radical by reduction or radical coupling.
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Affiliation(s)
- Daniel J Keddie
- School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Q4001 Australia
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17
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Critically evaluated termination rate coefficients for free-radical polymerization: Experimental methods. Prog Polym Sci 2005. [DOI: 10.1016/j.progpolymsci.2005.02.001] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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18
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Aspée A, Maretti L, Scaiano JC. Monitoring photodecomposition of dibenzyl ketone within NaY zeolite with a pre-fluorescent nitroxide compound. Photochem Photobiol Sci 2005; 2:1125-9. [PMID: 14690224 DOI: 10.1039/b308638k] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Benzyl radicals derived from photodecomposition of dibenzyl ketone have been monitored in NaY zeolite using the pre-fluorescent probe 4-(3-hydroxy-2-methyl-4-quinolinoyloxy)-2,2,6,6-tetramethylpiperidine-1-oxyl free radical (QT). The steady-state and time-resolved fluorescence show a strong interaction of QT within the zeolite cavities. Furthermore, the increase in the fluorescence with the irradiation time reveals the efficient trapping of benzyl radicals by QT under vacuum. Dispersion of the zeolite composites in liquid polymers results in an improvement in the fluorescence measurement and faster kinetics in comparison with the solid samples. These results are interpreted in terms of partial refractive index matching as a consequence of polymer reptation into the zeolite cavities. Analysis of the fluorescence lifetime distribution shows the presence of different fluorescence ensembles with different fluorescence quantum yields, depending on the microenvironment within the zeolite particle. Pre-fluorescent probes offer a novel and useful methodology for studying radical processes in zeolites.
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Affiliation(s)
- Alexis Aspée
- Department of Chemistry, University of Ottawa, 10 Mari-Curie, Ottawa, Ontario, Canada K1N 6N5
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19
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Bian ZY, Guo XQ, Zhao YB, Du JO. Probing the Hydroxyl Radical-Mediated Reactivity of Peroxynitrite by a Spin-Labeling Fluorophore. ANAL SCI 2005; 21:553-9. [PMID: 15913147 DOI: 10.2116/analsci.21.553] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The decomposition of peroxynitrite at physiological pH yielded a hydroxyl radical, which reacted rapidly with dimethyl sulfoxide (DMSO) to produce a methyl radical (*CH3), which was then trapped by a spin-label fluorophore nitroxide-linked naphthalene (NTEMPO), a carbon-centered radical probe with a low fluorescence intensity, and transformed to a stable diamagnetic O-alkoxyamine, a high-fluorescence compound. The fluorescence increment was proportional to the concentration of the hydroxyl radical, and then to the concentration of peroxynitrite. NTEMPO therefore was demonstrated to be capable of detecting hydroxyl radicals generated from peroxynitrite, and the method was proved to be simple and sensitive. The hydroxyl radical-mediated reactivities of peroxynitrite to several amino acids, such as tyrosine, phenylalanine and histidine, were then evaluated by the spin-labeling fluorophore NTEMPO at pH 7.4 and, 37 degrees C. The obtained data were in good agreement with the reference values, respectively.
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Affiliation(s)
- Zhao-Yang Bian
- Key Laboratory of Analytical Sciences of MOE, Department of Chemistry, Xiamen University, Xiamen 361005, China
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21
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Aliaga C, Aspée A, Scaiano JC. A New Method to Study Antioxidant Capability: Hydrogen Transfer from Phenols to a Prefluorescent Nitroxide. Org Lett 2003; 5:4145-8. [PMID: 14572270 DOI: 10.1021/ol035589w] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text]. Rate constants for hydrogen abstraction from phenols by a prefluorescent-TEMPO probe are reported. The nitroxide is employed as a potential model of peroxyl radicals. The probe works by nitroxide suppression of the fluorescence of the chromophore. The fluorescence is restored when the nitroxide abstracts a hydrogen atom to produce the diamagnetic hydroxylamine. The phenols studied in this project exhibited rate constants between 0.003 and 0.2 M(-1) s(-1). A deuterium isotope effect of 10 for TROLOX confirms that the mechanism is dominated by hydrogen transfer.
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Affiliation(s)
- Carolina Aliaga
- Department of Chemistry, University of Ottawa, Ottawa, Canada K1N 6N5
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22
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Kelemen P, Lugtenburg J, Klumperman B. 15N NMR spectroscopy of labeled alkoxyamines. 15N-labeled model compounds for nitroxide-trapping studies in free-radical (Co)polymerization. J Org Chem 2003; 68:7322-8. [PMID: 12968882 DOI: 10.1021/jo034667q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Eight (15)N-labeled derivatives of 1-ethoxy-2,2,6,6-tetramethylpiperidine were synthesized in order to investigate the effects of their structural units on (15)N NMR spectra. A single peak is found for each alkoxyamine. The chemical shift depends extensively on the nature of the alpha carbon atom of the alkoxy group. The remote functional group attached to position 4 of the piperidine ring has a smaller but still significant effect. The results of the (15)N NMR measurements are supported by the detection of the N-H and N-C spin-spin coupling from the (1)H and (13)C NMR. The investigated alkoxyamines are model compounds for the radical-trapping products of styryl, methyl methacryloyl, alpha-methylstyryl, and methyl acryloyl radicals by (15)N-labeled nitroxides. The potential of (15)N NMR spectroscopy to analyze such products is discussed. In addition, it is shown that the (13)C chemical shifts of the alpha carbon atom of the alkoxy group fall in an empty part of the (13)C NMR spectrum, which allows the identification of trapped (macro)radicals via natural abundance (13)C NMR.
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Affiliation(s)
- Peter Kelemen
- Laboratory of Polymer Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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23
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Wright PJ, English AM. Scavenging with TEMPO* to identify peptide- and protein-based radicals by mass spectrometry: advantages of spin scavenging over spin trapping. J Am Chem Soc 2003; 125:8655-65. [PMID: 12848573 DOI: 10.1021/ja0291888] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The detection and characterization of radicals in biomolecules are challenging due to their high reactivity and low concentration. Mass spectrometry (MS) provides a tool for the unambiguous identification of protein-based radicals by exploiting their reactivity with suitable reagents. To date, protein-radical detection by MS has been modeled after electron paramagnetic resonance experiments, in which diamagnetic spin traps, such as 3,5-dibromo-4-nitrosobenzene sulfonic acid, convert unstable radicals to more stable spin adducts. Since MS detects mass changes, and not unpaired spins, conversion of radicals to stable diamagnetic adducts is more desirable. The use of 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO(*)) in the MS identification of protein-based radicals was explored here to establish whether scavenging via radical combination would give rise to TEMPO adducts that were stable to MS analysis. The horseradish peroxidase/H(2)O(2) reaction was used to generate radicals in derivatives of tyrosine, tryptophan, and phenylalanine as models of protein-based radicals. TEMPO(*) was added as a radical scavenger, and the products were analyzed by electrospray ionization (ESI) MS. Dramatically higher mass-adduct yields were obtained using radical scavenging vs radical trapping, which greatly enhanced the sensitivity of radical detection. The efficiency of TEMPO(*) in protein radical scavenging was examined in horse heart myoglobin and cytochrome c peroxidase (CCP) from Saccharomyces cerevisiae. On H(2)O(2) binding to their ferric hemes, two oxidizing equivalents are transferred to the proteins as an Fe(IV)=O species and a polypeptide-based radical. In addition, CCP has been shown to reduce up to 10 equiv of H(2)O(2) using endogenous donors, thereby generating as many as 20 radicals on its polypeptide. Following myoglobin and CCP incubation with a 10-fold molar excess of H(2)O(2) and TEMPO(*), matrix-assisted laser desorption ionization (MALDI) time-of-flight analysis of the tryptic peptides derived from the proteins revealed 1 and 9 TEMPO adducts of myoglobin and CCP, respectively. Given the high scavenging efficiency of TEMPO(*) and the stability of TEMPO-labeled peptides in ESI and MALDI sources, scavenging by stable nitroxide radicals coupled with MS analysis should provide sensitive and powerful technology for the characterization of protein-based radicals.
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Affiliation(s)
- P John Wright
- Department of Chemistry and Biochemistry, Concordia University, 1455 de Maisonneuve Boulevard West, Montreal, Quebec, Canada H3G 1M8
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24
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Ricci A, Chrétien MN, Maretti L, Scaiano JC. TiO2-promoted mineralization of organic sunscreens in water suspension and sodium dodecyl sulfate micelles. Photochem Photobiol Sci 2003; 2:487-92. [PMID: 12803070 DOI: 10.1039/b212815b] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photostability of the widely used UVB sunscreen agents 2'-ethylhexyl-2-cyano-3-phenylcinnamate (1), 2-hydroxy-4-methoxybenzophenone (2), octyl salicilate (3), and 2'-ethylhexyl-4-methoxycinnamate (4) has been investigated under UVA irradiation in the absence and presence of TiO2, an inorganic filter commonly employed in combination with organic filters in sunscreen preparations. In the absence of TiO2, 1-3 are photostable and 4 undergoes the expected E-Z isomerization; the presence of TiO2 caused mineralization of the organic filters and, surprisingly, the process is noticeably faster in the presence of surfactant than in sunscreen and water suspensions. The results indicate that in water suspension, mineralization is likely to occur on or near the TiO2 particle surface; when the organic sunscreens are segregated in the micelle core, reactive radicals, produced during TiO2-promoted degradation of the micellar system, may participate in sunscreen degradation. In addition, a pre-fluorescent probe for carbon-centered radical detection, 4-(3-hydroxy-2-methyl-4-quinolineoxy)-2,2,6,6-tetramethylpiperidine-1-oxyl free radical or QT (5), was employed to demonstrate that carbon-centered radicals are evolved during micelle degradation and may participate in the mineralization of sunscreens.
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Affiliation(s)
- Andrea Ricci
- Department of Chemistry, Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, Canada K1N 6N5
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25
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Aspée A, García O, Maretti L, Sastre R, Scaiano JC. Free Radical Reactions in Poly(methyl methacrylate) Films Monitored Using a Prefluorescent Quinoline−TEMPO Sensor. Macromolecules 2003. [DOI: 10.1021/ma0212994] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alexis Aspée
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada, and Instituto de Ciencia y Tecnología de Polímeros (CSIC), Juan de la Cierva 3, Madrid 28006, Spain
| | - Olga García
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada, and Instituto de Ciencia y Tecnología de Polímeros (CSIC), Juan de la Cierva 3, Madrid 28006, Spain
| | - Luca Maretti
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada, and Instituto de Ciencia y Tecnología de Polímeros (CSIC), Juan de la Cierva 3, Madrid 28006, Spain
| | - Roberto Sastre
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada, and Instituto de Ciencia y Tecnología de Polímeros (CSIC), Juan de la Cierva 3, Madrid 28006, Spain
| | - J. C. Scaiano
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada, and Instituto de Ciencia y Tecnología de Polímeros (CSIC), Juan de la Cierva 3, Madrid 28006, Spain
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26
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Shipp DA, Solomon DH, Smith TA, Moad G. Chain Length Dependence of Radical−Radical Termination in Free Radical Polymerization: A Pulsed Laser Photolysis Investigation. Macromolecules 2003. [DOI: 10.1021/ma0209951] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Devon A. Shipp
- Polymer Science Group, Department of Chemical Engineering, The University of Melbourne, Victoria 3010, Australia
| | - David H. Solomon
- Polymer Science Group, Department of Chemical Engineering, The University of Melbourne, Victoria 3010, Australia
| | - Trevor A. Smith
- Photophysics Laboratory, School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Graeme Moad
- CSIRO Molecular Science, Bag 10, Clayton South 3169, Victoria, Australia
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27
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Coenjarts C, García O, Llauger L, Palfreyman J, Vinette AL, Scaiano JC. Mapping photogenerated radicals in thin polymer films: fluorescence imaging using a prefluorescent radical probe. J Am Chem Soc 2003; 125:620-1. [PMID: 12526647 DOI: 10.1021/ja028835s] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Prefluorescent radical probes, in which fluorescence is activated by radical trapping, and photoinitiators were used to detect radical generation in polymer films using fluorescence spectroscopy and microscopy. Prefluorescent radical probes are the foundation of a fluorescence imaging system for polymer films, that may serve both as a mechanistic tool in the study of photoinitiated radical processes in polymer films and in the preparation of functional fluorescent images.
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Affiliation(s)
- Chris Coenjarts
- Department of Chemistry, University of Ottawa, Canada K1N 6N5
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28
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Vana P, Yee LH, Davis TP. Multipulse Initiation in Pulsed Laser and Quenched Instationary Polymerization: Determination of the Propagation and Termination Rate Coefficients for Dicyclohexyl Itaconate Polymerization. Macromolecules 2002. [DOI: 10.1021/ma0118264] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Philipp Vana
- Centre for Advanced Macromolecular Design, School of Chemical Engineering and Industrial Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Lachlan H. Yee
- Centre for Advanced Macromolecular Design, School of Chemical Engineering and Industrial Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Thomas P. Davis
- Centre for Advanced Macromolecular Design, School of Chemical Engineering and Industrial Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
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Vana P, Yee LH, Barner-Kowollik C, Heuts JPA, Davis TP. Termination Rate Coefficient of Dimethyl Itaconate: Comparison of Modeling and Experimental Results. Macromolecules 2002. [DOI: 10.1021/ma011535v] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Philipp Vana
- Centre for Advanced Macromolecular Design, School of Chemical Engineering and Industrial Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Lachlan H. Yee
- Centre for Advanced Macromolecular Design, School of Chemical Engineering and Industrial Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Christopher Barner-Kowollik
- Centre for Advanced Macromolecular Design, School of Chemical Engineering and Industrial Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Johan P. A. Heuts
- Centre for Advanced Macromolecular Design, School of Chemical Engineering and Industrial Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Thomas P. Davis
- Centre for Advanced Macromolecular Design, School of Chemical Engineering and Industrial Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
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Ballesteros OG, Maretti L, Sastre R, Scaiano JC. Kinetics of Cap Separation in Nitroxide-Regulated “Living” Free Radical Polymerization: Application of a Novel Methodology Involving a Prefluorescent Nitroxide Switch. Macromolecules 2001. [DOI: 10.1021/ma0103831] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Olga García Ballesteros
- Instituto de Ciencia y Tecnología de Polímeros (CSIC), Juan de la Cierva 3. Madrid 28006, Spain, and Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Luca Maretti
- Instituto de Ciencia y Tecnología de Polímeros (CSIC), Juan de la Cierva 3. Madrid 28006, Spain, and Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Roberto Sastre
- Instituto de Ciencia y Tecnología de Polímeros (CSIC), Juan de la Cierva 3. Madrid 28006, Spain, and Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - J. C. Scaiano
- Instituto de Ciencia y Tecnología de Polímeros (CSIC), Juan de la Cierva 3. Madrid 28006, Spain, and Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
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Turro NJ, Lem G, Zavarine IS. A Living Free Radical Exchange Reaction for the Preparation of Photoactive End-Labeled Monodisperse Polymers. Macromolecules 2000. [DOI: 10.1021/ma001327n] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nicholas J. Turro
- Department of Chemistry, Columbia University, New York, New York 10027
| | - George Lem
- Department of Chemistry, Columbia University, New York, New York 10027
| | - Igor S. Zavarine
- Department of Chemistry, Columbia University, New York, New York 10027
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33
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Diffusion of a radical from an initiator of a free radical polymerization: a radical from AIBN. Chem Phys Lett 2000. [DOI: 10.1016/s0009-2614(00)01298-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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