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Ma L, Worland R, Tran T, Anastasio C. Evaluation of Probes to Measure Oxidizing Organic Triplet Excited States in Aerosol Liquid Water. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:6052-6062. [PMID: 37011016 DOI: 10.1021/acs.est.2c09672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Oxidizing triplet excited states of organic matter (3C*) drive numerous reactions in fog/cloud drops and aerosol liquid water (ALW). Quantifying oxidizing triplet concentrations in ALW is difficult because 3C* probe loss can be inhibited by the high levels of dissolved organic matter (DOM) and copper in particle water, leading to an underestimate of triplet concentrations. In addition, illuminated ALW contains high concentrations of singlet molecular oxygen (1O2*), which can interfere with 3C* probes. Our overarching goal is to find a triplet probe that has low inhibition by DOM and Cu(II) and low sensitivity to 1O2*. To this end, we tested 12 potential probes from a variety of compound classes. Some probes are strongly inhibited by DOM, while others react rapidly with 1O2*. One of the probe candidates, (phenylthiol)acetic acid (PTA), seems well suited for ALW conditions, with mild inhibition and fast rate constants with triplets, but it also has weaknesses, including a pH-dependent reactivity. We evaluated the performance of both PTA and syringol (SYR) as triplet probes in aqueous extracts of particulate matter. While PTA is less sensitive to inhibition than SYR, it results in lower triplet concentrations, possibly because it is less reactive with weakly oxidizing triplets.
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Affiliation(s)
- Lan Ma
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616, United States
| | - Reed Worland
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616, United States
| | - Theo Tran
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616, United States
| | - Cort Anastasio
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616, United States
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2
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Photocatalytic Deoxygenation of Sulfoxides Using Visible Light: Mechanistic Investigations and Synthetic Applications. ACS Catal 2020; 10:5814-5820. [PMID: 32582464 PMCID: PMC7304878 DOI: 10.1021/acscatal.0c00690] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/15/2020] [Indexed: 12/25/2022]
Abstract
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The
photocatalytic deoxygenation of sulfoxides to generate sulfides
facilitated by either Ir[(dF(CF3)ppy)2(dtbbpy)]PF6 or fac-Ir(ppy)3 is reported.
Mechanistic studies indicate that a radical chain mechanism operates,
which proceeds via a phosphoranyl radical generated from a radical/polar
crossover process. Initiation of the radical chain was found to proceed
via two opposing photocatalytic quenching mechanisms, offering complementary
reactivity. The mild nature of the radical deoxygenation process enables
the reduction of a wide range of functionalized sulfoxides, including
those containing acid-sensitive groups, in typically high isolated
yields.
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3
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Shinde RG, Khan AA, Barik A. Formation of two centre three electron bond by hydroxyl radical induced reaction of thiocoumarin: evidence from experimental and theoretical studies. Free Radic Res 2019; 53:629-640. [PMID: 31072168 DOI: 10.1080/10715762.2019.1617417] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Radiation chemical studies of thioesculetin (1), a thioketone derivative of coumarin, were performed by both pulse radiolysis technique and DFT calculations. Hydroxyl (•OH) radical reaction with 1 resulted transients absorbing at 320, 360 and 500 nm. To identify the nature of the transients, the reaction was studied with specific one-electron oxidant (N3•) radical, where 360 nm band was absent. The transient absorption at 500 nm was concentration-dependent. The overall impression for •OH radical reaction was that the transient absorbing at 320, 360 and 500 nm was due to sulphur centred monomer radical, hydroxysulfuranyl and dimer radical of 1 respectively. The equilibrium constant between the monomer to dimer radical was 3.75 × 104 M-1. From the transients' redox nature, it was observed that 57 and 24% of •OH radical yielded to oxidising and reducing products respectively. Further, the product analysis by HPLC suggested that the dimer radical disproportionate to esculetin and thioesculetin. DFT energy calculation for all the possible transients revealed that dimer radical has the lowest energy. The HOMO of 1 and its monomer radical suggested that the electron density was localised on the sulphur atom. The bond length between the two sulphur atoms in dimer radical was 2.88 Å which was less than the van der Waals distance. Bond order between the two sulphur atoms was 0.55, suggesting that the bond was two centre three electron (2c-3e). From TD-DFT calculation, the electronic transition of dimer radical was at 479 nm which was in close agreement with the experimental value. The nature of the electronic transition was σ → σ* from a 2c - 3e bond.
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Affiliation(s)
- Rupali G Shinde
- a Department of Chemistry , Savitribai Phule Pune University , Pune , India.,b Radiation and Photochemistry Division , Bhabha Atomic Research Centre , Mumbai , India
| | - Ayesha A Khan
- a Department of Chemistry , Savitribai Phule Pune University , Pune , India
| | - Atanu Barik
- b Radiation and Photochemistry Division , Bhabha Atomic Research Centre , Mumbai , India
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4
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Sulfur Radicals and Their Application. Top Curr Chem (Cham) 2018; 376:22. [DOI: 10.1007/s41061-018-0197-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/11/2018] [Indexed: 12/11/2022]
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5
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Yamamoto T, Ammam M, Roberts SA, Wilson GS, Glass RS. Suzuki–Miyaura synthesis of m-terphenyl thioethers and their facilitated oxidation caused by through-space π⋯S⋯π interaction. Tetrahedron 2016. [DOI: 10.1016/j.tet.2016.03.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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6
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Tojo S, Fujitsuka M, Majima T. Structures of 4-substituted thioanisole radical cations studied by time-resolved resonance Raman spectroscopy during pulse radiolysis and theoretical calculations. RSC Adv 2016. [DOI: 10.1039/c6ra21460f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The structures of 4-substituted thioanisole radical cations were studied by time-resolved resonance Raman spectroscopy during pulse radiolysis and DFT calculation, indicating importance of charge and spin distributions toward the dimerization.
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Affiliation(s)
- Sachiko Tojo
- The Institute of Scientific and Industrial Research (SANKEN)
- Osaka University
- Ibaraki
- Japan
| | - Mamoru Fujitsuka
- The Institute of Scientific and Industrial Research (SANKEN)
- Osaka University
- Ibaraki
- Japan
| | - Tetsuro Majima
- The Institute of Scientific and Industrial Research (SANKEN)
- Osaka University
- Ibaraki
- Japan
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7
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Monney NPA, Bally T, Yamamoto T, Glass RS. Spectroscopic Evidence for Through-Space Arene–Sulfur–Arene Bonding Interaction in m-Terphenyl Thioether Radical Cations. J Phys Chem A 2015; 119:12990-8. [DOI: 10.1021/acs.jpca.5b09665] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Thomas Bally
- Department
of Chemistry, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Takuhei Yamamoto
- Department
of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States
| | - Richard S. Glass
- Department
of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States
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8
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Singh BG, Thomas E, Sawant SN, Takahashi K, Dedachi K, Iwaoka M, Priyadarsini KI. Radical Cations of Aromatic Selenium Compounds: Role of Se···X Nonbonding Interactions. J Phys Chem A 2013; 117:9259-65. [DOI: 10.1021/jp405798h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - Kohei Takahashi
- Department
of Chemistry, School of Science, Tokai University, Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan
| | - Kenchi Dedachi
- Department
of Chemistry, School of Science, Tokai University, Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan
| | - Michio Iwaoka
- Department
of Chemistry, School of Science, Tokai University, Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan
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Sunil Paul MM, Aravind UK, Pramod G, Aravindakumar CT. Oxidative degradation of fensulfothion by hydroxyl radical in aqueous medium. CHEMOSPHERE 2013; 91:295-301. [PMID: 23273737 DOI: 10.1016/j.chemosphere.2012.11.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Revised: 11/06/2012] [Accepted: 11/09/2012] [Indexed: 06/01/2023]
Abstract
Oxidative degradation of fensulfothion, a model organophosphorus compound, has been investigated by pulse radiolysis and H2O2/UV photolysis. A nearly complete transformation of fensulfothion was observed within 4min of irradiation. Very little Total Organic Carbon (TOC) reduction was obtained at this time scale. When the product studies at this stage were conducted using LC-MS/MS analyses, nearly 20 transformation products were obtained. The entire products were identified as from the reaction of OH with fensulfothion or with some of its initially transformed products. Nearly 80% reduction in TOC was observed when photolysis was conducted using higher concentrations of H2O2 at longer time scale. A reaction rate constant (bimolecular) of 1.10×10(10)dm(3)mol(-1)s(-1) was obtained for the reaction of OH with fensulfothion using pulse radiolysis technique. The transient absorption spectrum obtained from the reaction of OH has a maximum at 280nm and a weak, broad maximum around 500nm along with a small shoulder around 340nm. The intermediate spectrum is assigned to the radical cation of fensulfothion (3) and the hydroxyl radical adducts (1 and 2). This assignment is supported by the intermediate spectrum (λmax at 280nm) from the reaction of sulfate radical anion (SO4(-)) (k2=3.20×10(9)dm(3)mol(-1)s(-1)) which is a one electron oxidant. It is thus demonstrated that the combination of both pulse radiolysis and the product estimation using LC-MS/MS is ideal in probing the complete mechanism which is very important in the mineralization reactions using Advanced Oxidation Processes.
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Affiliation(s)
- M M Sunil Paul
- School of Chemical Sciences, Mahatma Gandhi University, Kottayam, India.
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Prasanthkumar KP, Suresh CH, Aravindakumar CT. Oxidation reactions of 2-thiouracil: a theoretical and pulse radiolysis study. J Phys Chem A 2012; 116:10712-20. [PMID: 23061532 DOI: 10.1021/jp303808r] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reaction of hydroxyl radical ((•)OH) with the nucleic acid base analogue 2-thiouracil (1) has been studied by pulse radiolysis experiments and DFT. The generic intermediate radicals feasible for the (•)OH reactions with 1, namely, one electron oxidation product (1(•+)), (•)OH-adducts (3(•), 4(•), and 5(•)), and H-abstracted radicals (6(•) and 7(•)), were characterized by interpreting their electronic and structural properties along with calculated energetics and UV-vis spectra. Pulse radiolysis experiments showed that the transient formed in the reaction of (•)OH with 1 in water at pH 6.5 has λ(max) at 430 nm. A bimolecular rate constant, k(2) of 9.6 × 10(9) M(-1) s(-1), is determined for this reaction via competition kinetics with 2-propanol. The experiments suggested that the transient species could be a dimer radical cation 2(•+), formed by the reaction of 1 with the radical cation 1(•+). For this reaction, an equilibrium constant of 4.7 × 10(3) M(-1) was determined. The transient formed in the reaction of 1 with pulse radiolytically produced Br(2)(•-) at pH 6.5 as well as Cl(2)(•-) at pH 1 has also produced λ(max) at 430 nm and suggested the formation of 2(•+). The calculated UV-vis spectra of the transient species (1(•+), 3(•), 4(•), 5(•), 6(•), and 7(•)) showed no resemblance to the experimental spectra, while that of 2(•+) (λ(max) = 420 nm) agreed well with the experimental value and thus confirmed the formation of 2(•+). The 420 nm peak was due to σ → σ* electronic excitation centered on a 2-center-3-electron (2c-3e) sulfur-sulfur bond [-S∴S-]. 2(•+) is the first reported example of a dimer radical cation in a pyrimidine heterocyclic system. Further, 5-C and 6-C substituted (substituents are -F, -Cl, -NH(2), -N(CH(3))(2), -OCH(3), -CF(3), -CH(3), -CH(2)CH(3), n-propyl, phenyl, and benzyl) and 5,6-disubstituted 2-thiouracil systems have been characterized by DFT and found that the reaction (1 + 1(•+) → 2(•+)) is exergonic (1.12-13.63 kcal/mol) for many of them.
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Affiliation(s)
- K P Prasanthkumar
- School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686560, India
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11
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Lanzalunga O, Lapi A. Recent photo- and radiation chemical studies of sulfur radical cations. J Sulphur Chem 2011. [DOI: 10.1080/17415993.2011.619536] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Osvaldo Lanzalunga
- a Dipartimento di Chimica and IMC-CNR, Sezione Meccanismi di Reazione , Università “La Sapienza” , P.le A. Moro, 5 I-00185 , Rome , Italy
| | - Andrea Lapi
- a Dipartimento di Chimica and IMC-CNR, Sezione Meccanismi di Reazione , Università “La Sapienza” , P.le A. Moro, 5 I-00185 , Rome , Italy
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12
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Baciocchi E, Bettoni M, Del Giacco T, Lanzalunga O, Mazzonna M, Mencarelli P. Structure and C−S Bond Cleavage in Aryl 1-Methyl-1-arylethyl Sulfide Radical Cations. J Org Chem 2010; 76:573-82. [DOI: 10.1021/jo102086f] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Enrico Baciocchi
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università di Roma La Sapienza, P.le A. Moro 5, 00185 Rome, Italy
| | - Marta Bettoni
- Dipartimento di Chimica and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia, via Elce di Sotto 8, 06123 Perugia, Italy
| | - Tiziana Del Giacco
- Dipartimento di Chimica and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia, via Elce di Sotto 8, 06123 Perugia, Italy
| | - Osvaldo Lanzalunga
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università di Roma La Sapienza, P.le A. Moro 5, 00185 Rome, Italy
| | - Marco Mazzonna
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università di Roma La Sapienza, P.le A. Moro 5, 00185 Rome, Italy
| | - Paolo Mencarelli
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università di Roma La Sapienza, P.le A. Moro 5, 00185 Rome, Italy
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Gaikwad P, Priyadarsini KI, Naumov S, Rao BSM. Radiation and quantum chemical studies of chalcone derivatives. J Phys Chem A 2010; 114:7877-85. [PMID: 20617801 DOI: 10.1021/jp103382x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reactions of oxidizing radicals ((*)OH, Br(2)(*-), and SO(4)(*-)) with -OH-, -CH(3)-, or -NH(2)-substituted indole chalcones and hydroxy benzenoid chalcones were studied by radiation and quantum chemical methods. The (*)OH radical was found to react by addition at diffusion-controlled rates (k = 1.1-1.7 x 10(10) dm(3) mol(-1) s(-1)), but Br(2)(*-) radical reacted by 2 orders of magnitude lower. Quantum chemical calculations at the B3LYP/6-31+G(d,p) level of theory have shown that the (C2-OH)(*), (C11-OH)(*), and (C10-OH)(*) adducts of the indole chalcones and the (C7-OH)(*) and (C8-OH)(*) adducts of the hydroxy benzenoid chalcones are more stable with DeltaH = -39 to -28 kcal mol(-1) and DeltaG = -32 to -19 kcal mol(-1). This suggests that (*)OH addition to the alpha,beta-unsaturated bond is a major reaction channel in both types of chalcones and is barrierless. The stability and lack of dehydration of the (*)OH adducts arise from two factors: strong frontier orbital interaction due to the low energy gap between interacting orbitals and the negligible Coulombic repulsion due to small absolute values of Mulliken charges. The transient absorption spectrum measured in the (*)OH radical reaction with all the indole chalcone derivatives exhibited a maximum at 390 nm, which is in excellent agreement with the computed value (394 nm). The formation of three phenolic products under steady-state radiolysis is in line with the three stable (*)OH adducts predicted by theory. Independent of the substituent, identical spectra (lambda(max) = 330-360 and approximately 580 nm) were obtained on one-electron oxidation of the three indole chalcones. MO calculations predict the deprotonation from the -NH group is more efficient than from the substituent due to the larger electron density on the N1 atom forming the chalcone indolyl radical. Its reduction potential was determined to be 0.56 V from the ABTS(*-)/ABTS(2-) couple. In benzenoid chalcones, the (*)OH adduct spectrum is characterized by a peak at 270 nm and a broad maximum centered in the range 430-450 nm with an intense bleaching at 340 nm. The spectrum formed by electron transfer in these derivatives with lambda(max) = 280 and 380 nm (epsilon(280) = 5000 dm(3) mol(-1) cm(-1) and epsilon(380) = 700 dm(3) mol(-1) cm(-1)) was assigned to its phenoxyl radical. Our pulse radiolysis experiments in combination with quantum chemical calculations demonstrate that chalcones are efficient scavengers of damaging oxyl radicals.
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Affiliation(s)
- P Gaikwad
- National Centre for Free Radical Research, Department of Chemistry, University of Pune, Pune 411 007, India
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14
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Anodic oxidation of m-terphenyl thio-, seleno- and telluroethers: Lowered oxidation potentials due to chalcogen···π interaction. PURE APPL CHEM 2010. [DOI: 10.1351/pac-con-09-08-10] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The electrochemistry of m-terphenylthio-, seleno-, and telluroethers was studied using cyclic voltammetry in acetonitrile. All of the compounds studied showed irreversible oxidations. The first oxidation potentials for the thio- and selenoethers are less positive than expected. This facilitation in oxidation is ascribed to through-space S···π and Se···π inter-action, respectively, on removal of an electron. No evidence for a comparable effect was found for the phenyltelluro-ethers studied.
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Shirdhonkar M, Mohan H, Maity D, Rao B. Oxidation of phenyl vinyl sulphide and phenyl vinyl sulphoxide in aqueous solution: A pulse radiolysis and theoretical study. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.07.057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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Houmam A. Electron Transfer Initiated Reactions: Bond Formation and Bond Dissociation. Chem Rev 2008; 108:2180-237. [PMID: 18620366 DOI: 10.1021/cr068070x] [Citation(s) in RCA: 199] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Baciocchi E, Del Giacco T, Lanzalunga O, Mencarelli P, Procacci B. Photosensitized Oxidation of Alkyl Phenyl Sulfoxides. C−S Bond Cleavage in Alkyl Phenyl Sulfoxide Radical Cations. J Org Chem 2008; 73:5675-82. [DOI: 10.1021/jo801088n] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Enrico Baciocchi
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Sapienza Università di Roma, P.le A. Moro 5, 00185 Rome, Italy, and Dipartimento di Chimica and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia, via Elce di sotto 8, 06123 Perugia, Italy
| | - Tiziana Del Giacco
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Sapienza Università di Roma, P.le A. Moro 5, 00185 Rome, Italy, and Dipartimento di Chimica and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia, via Elce di sotto 8, 06123 Perugia, Italy
| | - Osvaldo Lanzalunga
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Sapienza Università di Roma, P.le A. Moro 5, 00185 Rome, Italy, and Dipartimento di Chimica and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia, via Elce di sotto 8, 06123 Perugia, Italy
| | - Paolo Mencarelli
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Sapienza Università di Roma, P.le A. Moro 5, 00185 Rome, Italy, and Dipartimento di Chimica and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia, via Elce di sotto 8, 06123 Perugia, Italy
| | - Barbara Procacci
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Sapienza Università di Roma, P.le A. Moro 5, 00185 Rome, Italy, and Dipartimento di Chimica and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia, via Elce di sotto 8, 06123 Perugia, Italy
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18
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Shirdhonkar M, Mohan H, Maity D, Rao B. Oxidation of phenyl trifluoromethyl sulphide: A pulse radiolysis and theoretical study. J Photochem Photobiol A Chem 2008. [DOI: 10.1016/j.jphotochem.2007.10.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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19
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Mishra B, Kumbhare LB, Jain VK, Priyadarsini KI. Pulse Radiolysis Studies on Reactions of Hydroxyl Radicals with Selenocystine Derivatives. J Phys Chem B 2008; 112:4441-6. [DOI: 10.1021/jp709880b] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mishra B, Kumar BS, Priyadarsini K. Pulse and γ-radiolysis studies on aqueous solution of 1,1′-dimethyl-2-selenourea. Radiat Phys Chem Oxf Engl 1993 2008. [DOI: 10.1016/j.radphyschem.2007.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Rajkumar E, Rajagopal S. Photoinduced electron transfer reaction of tris(4,4′-dicarboxyl-2,2′-bipyridine)ruthenium(ii) ion with organic sulfides. Photochem Photobiol Sci 2008; 7:1407-14. [DOI: 10.1039/b806974c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bartoszewicz J, Hug GL, Pietrzak M, Kozubek H, Paczkowski J, Marciniak B. Benzophenone−Phenylthioacetic Acid Tetraalkylammonium Salts as Effective Initiators of Free-Radical Photopolymerization of Vinyl Monomers, Mechanistic Studies. Macromolecules 2007. [DOI: 10.1021/ma071581g] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jarogniew Bartoszewicz
- Faculty of Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland, Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and University of Technology and Life Sciences, Faculty of Chemical Technology and Engineering, 85-326 Bydgoszcz, Poland
| | - Gordon L. Hug
- Faculty of Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland, Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and University of Technology and Life Sciences, Faculty of Chemical Technology and Engineering, 85-326 Bydgoszcz, Poland
| | - Marek Pietrzak
- Faculty of Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland, Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and University of Technology and Life Sciences, Faculty of Chemical Technology and Engineering, 85-326 Bydgoszcz, Poland
| | - Halina Kozubek
- Faculty of Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland, Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and University of Technology and Life Sciences, Faculty of Chemical Technology and Engineering, 85-326 Bydgoszcz, Poland
| | - Jerzy Paczkowski
- Faculty of Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland, Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and University of Technology and Life Sciences, Faculty of Chemical Technology and Engineering, 85-326 Bydgoszcz, Poland
| | - Bronislaw Marciniak
- Faculty of Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland, Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and University of Technology and Life Sciences, Faculty of Chemical Technology and Engineering, 85-326 Bydgoszcz, Poland
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23
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Modification of photochemical pathways of sensitized oxidation of phenylthioacetic acid. J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2007.04.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Bobrowski K, Hug GL, Pogocki D, Marciniak B, Schöneich C. Stabilization of sulfide radical cations through complexation with the peptide bond: mechanisms relevant to oxidation of proteins containing multiple methionine residues. J Phys Chem B 2007; 111:9608-20. [PMID: 17658786 DOI: 10.1021/jp071191w] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The recent study on the *OH-induced oxidation of calmodulin, a regulatory "calcium sensor" protein containing nine methionine (Met) residues, has supported the first experimental evidence in a protein for the formation of S therefore N three-electron bonded radical complexes involving the sulfur atom of a methionine residue and the amide groups in adjacent peptide bonds. To characterize reactions of oxidized methionine residues in proteins containing multiple methionine residues in more detail, in the current study, a small model cyclic dipeptide, c-(L-Met-L-Met), was oxidized by *OH radicals generated via pulse radiolysis and the ensuing reactive intermediates were monitored by time-resolved UV-vis spectroscopic and conductometric techniques. The picture that emerges from this investigation shows there is an efficient formation of the Met (S therefore N) radicals, in spite of the close proximity of two sulfur atoms, located in the side chains of methionine residues, and in spite of the close proximity of sulfur atoms and oxygen atoms, located in the peptide bonds. Moreover, it is shown, for the first time, that the formation of Met(S therefore N) radicals can proceed directly, via H+-transfer, with the involvement of hydrogen from the peptide bond to an intermediary hydroxysulfuranyl radical. Ultimately, the Met(S therefore N) radicals decayed via two different pH-dependent reaction pathways, (i) conversion into sulfur-sulfur, intramolecular, three-electron-bonded radical cations and (ii) a proposed hydrolytic cleavage of the protonated form of the intramolecular, three-electron-bonded radicals [Met(S therefore N)/Met(S therefore NH)+] followed by electron transfer and decarboxylation. Surprisingly, also alpha-(alkylthio)alkyl radicals enter the latter mechanism in a pH-dependent manner. Density functional theory computations were performed on the model c-(L-Met-Gly) and its radicals in order to obtain optimizations and energies to aid in the interpretation of the experiments on c-(L-Met-L-Met).
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25
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Baciocchi E, Del Giacco T, Gerini MF, Lanzalunga O. Rates of C−S Bond Cleavage in tert-Alkyl Phenyl Sulfide Radical Cations. Org Lett 2006; 8:641-4. [PMID: 16468731 DOI: 10.1021/ol052834y] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] Radical cations of tert-alkyl phenyl sulfides 1-4 have been generated photochemically in MeCN in the presence of the N-methoxyphenanthridinium cation (MeOP(+)), and the rates of C-S bond cleavage have been determined by laser flash photolysis.
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Affiliation(s)
- Enrico Baciocchi
- Dipartimento di Chimica, Università La Sapienza and IMC-CNR, Sezione Meccanismi di Reazione, P.le A. Moro, 5 I-00185 Rome, Italy.
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26
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Mishra B, Priyadarsini KI, Mohan H. Effect of pH on One-Electron Oxidation Chemistry of Organoselenium Compounds in Aqueous Solutions. J Phys Chem A 2006; 110:1894-900. [PMID: 16451022 DOI: 10.1021/jp055784n] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Pulse radiolysis coupled with absorption detection has been employed to study one-electron oxidation of selenomethionine (SeM), selenocystine (SeCys), methyl selenocysteine (MeSeCys), and selenourea (SeU) in aqueous solutions. Hydroxyl radicals (*OH) in the pH range from 1 to 7 and specific one-electron oxidants Cl2*- (pH 1) and Br2*- (pH 7) have been used to carry out the oxidation reactions. The bimolecular rate constants for these reactions were reported to be in the range of 2 x 10(9) to 10 x 10(9) M(-1) s(-1). Reactions of oxidizing radicals with all these compounds produced selenium-centered radical cations. The structure and stability of the radical cation were found to depend mainly on the substituent and pH. SeM, at pH 7, produced a monomer radical cation (lambdamax approximately 380 nm), while at pH 1, a dimer radical cation was formed by the interaction between oxidized and parent SeM (lambdamax approximately 480 nm). Similarly, SeCys, at pH 7, on one-electron oxidation, produced a monomer radical cation (lambdamax approximately 460 nm), while at pH 1, the reaction produced a transient species with (lambdamax approximately 560 nm), which is also a monomer radical cation. MeSeCys on one-electron oxidation in the pH range from 1 to 7 produced monomer radical cations (lambdamax approximately 350 nm), while at pH < 0, the reaction produced dimer radical cations (lambdamax approximately 460 nm). SeU at all the pH ranges produced dimer radical cations (lambdamax approximately 410 nm). The association constants of the dimer radical cations of SeM, MeSeCys, and SeU were determined by following absorption changes at lambdamax as a function of concentration. From these studies it is concluded that formation of monomer and dimer radical cations mainly depends on the substitution, pH, and the heteroatoms like N and O. The availability of a lone pair on an N or O atom at the beta or gamma position results in monomer radical cations having intramolecular stabilization. When such a lone pair is not available, the monomer radical cation is converted into a dimer radical cation which acquires intermolecular stabilization by the other selenium atom. The pH dependency confirms the role of protonation on stabilization. The oxidation chemistry of these selenium compounds is compared with that of their sulfur analogues.
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Affiliation(s)
- B Mishra
- Radiation & Photo Chemistry Division, Bhabha Atomic Research Center, Trombay, Mumbai 400 085, India
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27
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Filipiak P, Hug GL, Marciniak B. Photochemistry of carboxylic acids containing the phenyl and thioether groups: Steady-state and laser flash photolysis studies. J Photochem Photobiol A Chem 2006. [DOI: 10.1016/j.jphotochem.2005.06.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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28
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Baciocchi E, Bietti M, Lanzalunga O. Fragmentation reactions of radical cations. J PHYS ORG CHEM 2006. [DOI: 10.1002/poc.1096] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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29
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Mohan H, Mittal JP. Effect of substituents on different channels of OH radical reaction with substituted organic sulfides. Radiat Phys Chem Oxf Engl 1993 2005. [DOI: 10.1016/j.radphyschem.2005.04.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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30
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Strzelczak G, Korzeniowska-Sobczuk A, Bobrowski K. Electron spin resonance study of radiation-induced radicals in polycrystalline aromatic carboxylic acids containing a thioether group. Radiat Phys Chem Oxf Engl 1993 2005. [DOI: 10.1016/j.radphyschem.2004.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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31
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Filipiak P, Hug GL, Carmichael I, Korzeniowska-Sobczuk A, Bobrowski K, Marciniak B. Lifetimes and Modes of Decay of Sulfur-Centered Radical Zwitterions Containing Carboxylate and Phenyl Groups. J Phys Chem A 2004. [DOI: 10.1021/jp036962k] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Piotr Filipiak
- Faculty of Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland, Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland
| | - Gordon L. Hug
- Faculty of Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland, Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland
| | - Ian Carmichael
- Faculty of Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland, Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland
| | - Anna Korzeniowska-Sobczuk
- Faculty of Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland, Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland
| | - Krzysztof Bobrowski
- Faculty of Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland, Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland
| | - Bronislaw Marciniak
- Faculty of Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland, Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland
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32
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Baciocchi E, Gerini MF. Rotational Barriers, Charges, and Spin Densities in Alkyl Aryl Sulfide Radical Cations: A Density Functional Study. J Phys Chem A 2004. [DOI: 10.1021/jp0367124] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Enrico Baciocchi
- Università degli Studi di Roma “La Sapienza”, P. le A. Moro 5, 00185, Roma, Italy
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33
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Mishra B, Maity DK, Priyadarsini KI, Mohan H, Mittal JP. One-Electron Oxidation of Selenourea in Aqueous Solution. J Phys Chem A 2004. [DOI: 10.1021/jp0371130] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- B. Mishra
- Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - D. K. Maity
- Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - K. I. Priyadarsini
- Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - H. Mohan
- Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - J. P. Mittal
- Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
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34
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Noguera M, Bertran J, Sodupe M. A Quantum Chemical Study of Cu2+ Interacting with Guanine−Cytosine Base Pair. Electrostatic and Oxidative Effects on Intermolecular Proton-Transfer Processes. J Phys Chem A 2003. [DOI: 10.1021/jp036573q] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marc Noguera
- Departament de Química, Universitat Autònoma de Barcelona, Bellaterra 08193
| | - Joan Bertran
- Departament de Química, Universitat Autònoma de Barcelona, Bellaterra 08193
| | - Mariona Sodupe
- Departament de Química, Universitat Autònoma de Barcelona, Bellaterra 08193
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35
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Wrzyszczyñski A, Pietrzak M, Pa̧czkowski J. A Novel Approach to the Preparation of Dissociative Electron Transfer Photoinitiators for Free Radical Polymerization. Macromolecules 2003. [DOI: 10.1021/ma021679p] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrzej Wrzyszczyñski
- University of Technology and Agriculture, Faculty of Chemical Technology and Engineering, Seminaryjna 3, 85-326 Bydgoszcz, Poland
| | - Marek Pietrzak
- University of Technology and Agriculture, Faculty of Chemical Technology and Engineering, Seminaryjna 3, 85-326 Bydgoszcz, Poland
| | - Jerzy Pa̧czkowski
- University of Technology and Agriculture, Faculty of Chemical Technology and Engineering, Seminaryjna 3, 85-326 Bydgoszcz, Poland
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36
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Wrzyszczyński A, Pietrzak M, Bartoszewicz J, Kozubek H, Hug GL, Marciniak B, Paczkowski J. Unexpected Hofmann Elimination in the Benzophenone−(Phenylthio)acetic Tetrabutylammonium Salt Photoredox System. J Am Chem Soc 2003; 125:11182-3. [PMID: 16220924 DOI: 10.1021/ja036196v] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The triplet state of benzophenone was quenched by the tetrabutylammonium salt of (phenylthio)acetic acid in acetonitrile solutions. The quenching event, following laser flash photolysis, resulted in the formation of a transient ion pair consisting of the benzophenone radical anion and the tetrabutylammonium cation. Subsequently this ion pair decays with the quaternary ammonium cation undergoing a Hofmann elimination to form butane-1 and tributylamine, which were detected in steady-state irradiation. This appears to be the first report of an ion pair consisting of a benzophenone radical anion and an organic cation (nonradical), in addition to the first report of a photoinduced Hofmann elimination in quaternary ammonium ions.
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Affiliation(s)
- Andrzej Wrzyszczyński
- Faculty of Chemical Technology and Engineering, University of Technology and Agriculture, Bydgoszcz, Poland
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