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Wojnárovits L, Takács E. Rate constants of dichloride radical anion reactions with molecules of environmental interest in aqueous solution: a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:41552-41575. [PMID: 34086177 PMCID: PMC8354983 DOI: 10.1007/s11356-021-14453-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 05/13/2021] [Indexed: 05/14/2023]
Abstract
Natural waters, water droplets in the air at coastal regions and wastewaters usually contain chloride ions (Cl-) in relatively high concentrations in the milimolar range. In the reactions of highly oxidizing radicals (e.g., •OH, •NO3, or SO4•-) in the nature or during wastewater treatment in advanced oxidation processes the chloride ions easily transform to chlorine containing radicals, such as Cl•, Cl2•-, and ClO•. This transformation basically affects the degradation of organic molecules. In this review about 400 rate constants of the dichloride radical anion (Cl2•-) with about 300 organic molecules is discussed together with the reaction mechanisms. The reactions with phenols, anilines, sulfur compounds (with sulfur atom in lower oxidation state), and molecules with conjugated electron systems are suggested to take place with electron transfer mechanism. The rate constant is high (107-109 M-1 s-1) when the reduction potential the one-electron oxidized species/molecule couple is well below that of the Cl2•-/2Cl- couple.
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Affiliation(s)
- László Wojnárovits
- Radiation Chemistry Department, Institute for Energy Security and Environmental Safety, Centre for Energy Research, H-1121 Konkoly-Thege Miklós út, Budapest, 29-33, Hungary
| | - Erzsébet Takács
- Radiation Chemistry Department, Institute for Energy Security and Environmental Safety, Centre for Energy Research, H-1121 Konkoly-Thege Miklós út, Budapest, 29-33, Hungary.
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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: 21] [Impact Index Per Article: 1.8] [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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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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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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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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C–S bond cleavage in the sensitized photooxygenation of tert-alkyl phenyl sulfides. The role of superoxide anion. Tetrahedron 2006. [DOI: 10.1016/j.tet.2005.09.154] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Baciocchi E, Del Giacco T, Elisei F, Lapi A. Sulfur Radical Cations. Kinetic and Product Study of the Photoinduced Fragmentation Reactions of (Phenylsulfanylalkyl)trimethylsilanes and Phenylsulfanylacetic Acid Radical Cations. J Org Chem 2005; 71:853-60. [PMID: 16438494 DOI: 10.1021/jo051145x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Laser and steady-state photolysis, sensitized by NMQ+, of PhSCH(R)X 1-4 (R = H, Ph; X =SiMe3, CO2H) was carried out in CH3CN. The formation of 1+*-4+* was clearly shown. All radical cations undergo a fast first-order fragmentation reaction involving C-Si bond cleavage with 1+* and 2+* and C-C bond cleavage with 3+* and 4+*. The desilylation reaction of 1+* and 2+* was nucleophilically assisted, and the decarboxylation rates of 3+* and 4+* increased in the presence of H2O. A deuterium kinetic isotope effect of 2.0 was observed when H2O was replaced by D2O. Pyridines too were found to accelerate the decarboxylation rate of 3+* and 4+*. The rate increase, however, was not a linear function of the base concentration, but a plateau was reached. A fast and reversible formation of a H-bonded complex between the radical cation and the base is suggested, which undergoes C-C bond cleavage. It is probable that the H-bond complex undergoes first a rate determining proton-coupled electron transfer forming a carboxyl radical that then loses CO2. The steady-state photolysis study showed that PhSCH3 was the exclusive product formed from 1 and 3 whereas [PhS(Ph)CH-]2 was the only product with 3 and 4.
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Affiliation(s)
- Enrico Baciocchi
- Dipartimento di Chimica, Università La Sapienza, Piazzale A. Moro 5, 00185 Rome, Italy.
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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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Baciocchi E, Fabbri C, Lanzalunga O. Lignin Peroxidase-Catalyzed Oxidation of Nonphenolic Trimeric Lignin Model Compounds: Fragmentation Reactions in the Intermediate Radical Cations. J Org Chem 2003; 68:9061-9. [PMID: 14604381 DOI: 10.1021/jo035052w] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The H(2)O(2)-promoted oxidations of the two nonphenolic beta-O-aryl lignin model trimers 1 and 2, catalyzed by lignin peroxidase (LiP) at pH = 3.5, have been studied. The results have been compared with those obtained in the oxidation of 1 and 2 with the genuine one-electron oxidant potassium 12-tungstocobalt(III)ate. These models present a different substitution pattern of the three aromatic rings, and by one-electron oxidation, they form radical cations with the positive charge, which is localized in the dialkoxylated ring as also evidenced by a pulse radiolysis study. Both the oxidations with the enzymatic and with the chemical systems lead to the formation of products deriving from the cleavage of C-C and C-H bonds in a beta position with respect to the radical cation with the charge residing in the dialkoxylated ring (3,4-dimethoxybenzaldehyde (5) and a trimeric ketone 6 in the oxidation of 1 and a dimeric aldehyde 8 and a trimeric ketone 9 in the oxidation of 2). These products are accompanied by a dimeric aldehyde 7 in the oxidation of 1 and 4-methoxybenzaldehyde (10) in the oxidation of 2. The unexpected formation of these two products has been explained by suggesting that 1.+ and 2.+ can also undergo an intramolecular electron transfer leading to the radical cations 1a.+ and 2a.+ with the charge residing in a monoalkoxylated ring. The fast cleavage of a C-C bond beta to this ring, leading to 7 from 1.+ and to 10 from 2.+, is the driving force of the endoergonic electron transfer. A kinetic steady-state investigation of the LiP-catalyzed oxidation of the trimer 2, the dimeric model 1-(3,4-dimethoxyphenyl)-2-phenoxy-1-ethanol (4), and 3,4-dimethoxybenzyl alcohol (3) has indicated that the turnover number (k(cat)) and the affinity for the enzyme decrease significantly by increasing the size of the model compound. In contrast, the three substrates exhibited a very similar reactivity toward a chemical oxidant [Co(III)W]. This suggests a size-dependent interaction of the enzyme with the substrate which may influence the efficiency of the electron transfer.
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Affiliation(s)
- Enrico Baciocchi
- Dipartimento di Chimica, Università La Sapienza, Piazzale A. Moro 5, I-00185 Rome, Italy.
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Gawandi V, Mohan H, Mittal JP. Investigations on the nature of the transient species formed on pulse radiolysis of a aqueous solution of 4-(methylthio)benzoic acid. RESEARCH ON CHEMICAL INTERMEDIATES 2003. [DOI: 10.1163/156856703321328406] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Mohan H, Mittal JP. Different Channels of Hydroxyl Radical Reaction with Aryl Sulfides: Effect of the Substituents. J Phys Chem A 2002. [DOI: 10.1021/jp014265r] [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)
- Hari Mohan
- Radiation Chemistry & Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Jai P. Mittal
- Radiation Chemistry & Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
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Mohan H, Mittal JP. Spectral, Kinetics, and Redox Studies on the Transients Formed on Pulse Radiolysis of Aqueous Solution of (4-Methylthiophenyl)methanol. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2001. [DOI: 10.1246/bcsj.74.1649] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Asmus KD. Heteroatom-centered free radicals some selected contributions by radiation chemistry. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s0167-6881(01)80016-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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Mohan H, Mittal JP. Spectral, kinetics, and redox properties of the transients formed on one-electron oxidation of 4,4?-thiodiphenol: A pulse radiolysis study. INT J CHEM KINET 1999. [DOI: 10.1002/(sici)1097-4601(1999)31:9<603::aid-kin2>3.0.co;2-b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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