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Simões RG, Agapito F, Diogo HP, da Piedade MEM. Enthalpy of Formation of Anisole: Implications for the Controversy on the O–H Bond Dissociation Enthalpy in Phenol. J Phys Chem A 2014; 118:11026-32. [DOI: 10.1021/jp507267f] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ricardo G. Simões
- Centro
de Química e Bioquímica e Departamento de Química
e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Filipe Agapito
- Centro
de Química e Bioquímica e Departamento de Química
e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Hermínio P. Diogo
- Centro
de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa,1049-001 Lisboa, Portugal
| | - Manuel E. Minas da Piedade
- Centro
de Química e Bioquímica e Departamento de Química
e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
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Isse AA, Lin CY, Coote ML, Gennaro A. Estimation of Standard Reduction Potentials of Halogen Atoms and Alkyl Halides. J Phys Chem B 2010; 115:678-84. [DOI: 10.1021/jp109613t] [Citation(s) in RCA: 145] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Abdirisak A. Isse
- Department of Chemical Sciences, University of Padova, Via Marzolo, 1 - 35131 Padova, Italy, and ARC Centre of Excellence for Free-Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia
| | - Ching Yeh Lin
- Department of Chemical Sciences, University of Padova, Via Marzolo, 1 - 35131 Padova, Italy, and ARC Centre of Excellence for Free-Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia
| | - Michelle L. Coote
- Department of Chemical Sciences, University of Padova, Via Marzolo, 1 - 35131 Padova, Italy, and ARC Centre of Excellence for Free-Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia
| | - Armando Gennaro
- Department of Chemical Sciences, University of Padova, Via Marzolo, 1 - 35131 Padova, Italy, and ARC Centre of Excellence for Free-Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia
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Warren JJ, Tronic TA, Mayer JM. Thermochemistry of proton-coupled electron transfer reagents and its implications. Chem Rev 2010; 110:6961-7001. [PMID: 20925411 PMCID: PMC3006073 DOI: 10.1021/cr100085k] [Citation(s) in RCA: 1208] [Impact Index Per Article: 86.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Jeffrey J. Warren
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700
| | - Tristan A. Tronic
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700
| | - James M. Mayer
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700
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Warren JJ, Mayer JM. Predicting organic hydrogen atom transfer rate constants using the Marcus cross relation. Proc Natl Acad Sci U S A 2010; 107:5282-7. [PMID: 20215463 PMCID: PMC2851756 DOI: 10.1073/pnas.0910347107] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chemical reactions that involve net hydrogen atom transfer (HAT) are ubiquitous in chemistry and biology, from the action of antioxidants to industrial and metalloenzyme catalysis. This report develops and validates a procedure to predict rate constants for HAT reactions of oxyl radicals (RO(*)) in various media. Our procedure uses the Marcus cross relation (CR) and includes adjustments for solvent hydrogen-bonding effects on both the kinetics and thermodynamics of the reactions. Kinetic solvent effects (KSEs) are included by using Ingold's model, and thermodynamic solvent effects are accounted for by using an empirical model developed by Abraham. These adjustments are shown to be critical to the success of our combined model, referred to as the CR/KSE model. As an initial test of the CR/KSE model we measured self-exchange and cross rate constants in different solvents for reactions of the 2,4,6-tri-tert-butylphenoxyl radical and the hydroxylamine 2,2'-6,6'-tetramethyl-piperidin-1-ol. Excellent agreement is observed between the calculated and directly determined cross rate constants. We then extend the model to over 30 known HAT reactions of oxyl radicals with OH or CH bonds, including biologically relevant reactions of ascorbate, peroxyl radicals, and alpha-tocopherol. The CR/KSE model shows remarkable predictive power, predicting rate constants to within a factor of 5 for almost all of the surveyed HAT reactions.
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Affiliation(s)
- Jeffrey J. Warren
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98107-1700
| | - James M. Mayer
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98107-1700
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Das TN. Hidden chemistry in phenoxyl radical (C6H5O•) coupling reaction mechanism revealed. J PHYS ORG CHEM 2009. [DOI: 10.1002/poc.1534] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Mader EA, Manner VW, Markle TF, Wu A, Franz JA, Mayer JM. Trends in ground-state entropies for transition metal based hydrogen atom transfer reactions. J Am Chem Soc 2009; 131:4335-45. [PMID: 19275235 PMCID: PMC2723939 DOI: 10.1021/ja8081846] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reported herein are thermochemical studies of hydrogen atom transfer (HAT) reactions involving transition metal H-atom donors M(II)LH and oxyl radicals. [Fe(II)(H(2)bip)(3)](2+), [Fe(II)(H(2)bim)(3)](2+), [Co(II)(H(2)bim)(3)](2+), and Ru(II)(acac)(2)(py-imH) [H(2)bip = 2,2'-bi-1,4,5,6-tetrahydropyrimidine, H(2)bim = 2,2'-bi-imidazoline, acac = 2,4-pentandionato, py-imH = 2-(2'-pyridyl)imidazole)] each react with TEMPO (2,2,6,6-tetramethyl-1-piperidinoxyl) or (t)Bu(3)PhO(*) (2,4,6-tri-tert-butylphenoxyl) to give the deprotonated, oxidized metal complex M(III)L and TEMPOH or (t)Bu(3)PhOH. Solution equilibrium measurements for the reaction of [Co(II)(H(2)bim)(3)](2+) with TEMPO show a large, negative ground-state entropy for hydrogen atom transfer, -41 +/- 2 cal mol(-1) K(-1). This is even more negative than the DeltaS(o)(HAT) = -30 +/- 2 cal mol(-1) K(-1) for the two iron complexes and the DeltaS(o)(HAT) for Ru(II)(acac)(2)(py-imH) + TEMPO, 4.9 +/- 1.1 cal mol(-1) K(-1), as reported earlier. Calorimetric measurements quantitatively confirm the enthalpy of reaction for [Fe(II)(H(2)bip)(3)](2+) + TEMPO, thus also confirming DeltaS(o)(HAT). Calorimetry on TEMPOH + (t)Bu(3)PhO(*) gives DeltaH(o)(HAT) = -11.2 +/- 0.5 kcal mol(-1) which matches the enthalpy predicted from the difference in literature solution BDEs. A brief evaluation of the literature thermochemistry of TEMPOH and (t)Bu(3)PhOH supports the common assumption that DeltaS(o)(HAT) approximately 0 for HAT reactions of organic and small gas-phase molecules. However, this assumption does not hold for transition metal based HAT reactions. The trend in magnitude of |DeltaS(o)(HAT)| for reactions with TEMPO, Ru(II)(acac)(2)(py-imH) << [Fe(II)(H(2)bip)(3)](2+) = [Fe(II)(H(2)bim)(3)](2+) < [Co(II)(H(2)bim)(3)](2+), is surprisingly well predicted by the trends for electron transfer half-reaction entropies, DeltaS(o)(ET), in aprotic solvents. This is because both DeltaS(o)(ET) and DeltaS(o)(HAT) have substantial contributions from vibrational entropy, which varies significantly with the metal center involved. The close connection between DeltaS(o)(HAT) and DeltaS(o)(ET) provides an important link between these two fields and provides a starting point from which to predict which HAT systems will have important ground-state entropy effects.
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Affiliation(s)
- Elizabeth A Mader
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, USA
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Jacobsen H. Fluorine substituent effects on dihydrogen bonding of transition metal hydrides. Phys Chem Chem Phys 2009; 11:7231-40. [DOI: 10.1039/b900287a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bernardes CES, Minas da Piedade ME. Energetics of the O−H Bond and of Intramolecular Hydrogen Bonding in HOC6H4C(O)Y (Y = H, CH3, CH2CH═CH2, C≡CH, CH2F, NH2, NHCH3, NO2, OH, OCH3, OCN, CN, F, Cl, SH, and SCH3) Compounds. J Phys Chem A 2008; 112:10029-39. [DOI: 10.1021/jp804455u] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Carlos E. S. Bernardes
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1649-016 Lisboa, Portugal
| | - Manuel E. Minas da Piedade
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1649-016 Lisboa, Portugal
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A time-resolved photoacoustic calorimetry study for the determination of the partial volume and formation enthalpy of the SO3- aqueous radical. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.08.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Agapito F, Nunes PM, Costa Cabral BJ, Borges dos Santos RM, Martinho Simões JA. Energetic Differences between the Five- and Six-Membered Ring Hydrocarbons: Strain Energies in the Parent and Radical Molecules. J Org Chem 2008; 73:6213-23. [DOI: 10.1021/jo800690m] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Filipe Agapito
- Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal, Grupo de Física Matemática da Universidade de Lisboa, Av. Professor Gama Pinto 2, 1649-003 Lisboa, Portugal, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal, and Institute for Biotechnology and Bioengineering Centro de Biomedicina Molecular e Estrutural, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Paulo M. Nunes
- Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal, Grupo de Física Matemática da Universidade de Lisboa, Av. Professor Gama Pinto 2, 1649-003 Lisboa, Portugal, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal, and Institute for Biotechnology and Bioengineering Centro de Biomedicina Molecular e Estrutural, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Benedito J. Costa Cabral
- Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal, Grupo de Física Matemática da Universidade de Lisboa, Av. Professor Gama Pinto 2, 1649-003 Lisboa, Portugal, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal, and Institute for Biotechnology and Bioengineering Centro de Biomedicina Molecular e Estrutural, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Rui M. Borges dos Santos
- Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal, Grupo de Física Matemática da Universidade de Lisboa, Av. Professor Gama Pinto 2, 1649-003 Lisboa, Portugal, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal, and Institute for Biotechnology and Bioengineering Centro de Biomedicina Molecular e Estrutural, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - José A. Martinho Simões
- Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal, Grupo de Física Matemática da Universidade de Lisboa, Av. Professor Gama Pinto 2, 1649-003 Lisboa, Portugal, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal, and Institute for Biotechnology and Bioengineering Centro de Biomedicina Molecular e Estrutural, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
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