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Magnetic Field Effect on the Oxidation of Unsaturated Compounds by Molecular Oxygen. MAGNETOCHEMISTRY 2022. [DOI: 10.3390/magnetochemistry8040044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A quantum-chemical analysis of the effect of a constant magnetic field on radical formation in the processes of chain oxidation of organic compounds by molecular oxygen is presented. The calculation of the total electronic energies and thermodynamic functions of the compounds involved in the reactions was performed by the density functional method with the hybrid exchange-correlation functional of Becke, Lee, Yang and Parr DFT B3LYP/6-311G** using the NWChem software package. The effect of the magnetic field on the individual stages of chain oxidation is associated with the evolution of radical pairs. It is assumed that the dipole–dipole interaction in a radical pair is not averaged by the diffusion of radicals and should be taken into account. To a large extent, the magnetic field effect (MFE) value is influenced by the ratio between the relaxation time of the oscillatory-excited state in the radical pair (tvib) and the relaxation time of the inter-combination transitions (tst). Although the developed technique refers to liquid-phase reactions, it can be used to study the MFE for oxidation of biologically significant compounds in multiphase systems, such as micelles, liposomes and membranes.
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McKenzie I, Cordoni-Jordan D, Cannon J, Cottrell SP. Dynamics of polystyrene probed by muon spin spectroscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 33:065102. [PMID: 33325374 DOI: 10.1088/1361-648x/abc4ca] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Muon spin spectroscopic measurements were made on atactic low-molecular-weight (LMW) (1.3 kg mol-1) and high-molecular-weight (HMW) (202 kg mol-1) polystyrene. Muoniated cyclohexadienyl radicals, which are formed by muonium addition to the phenyl side groups, are used as local probes of bulk dynamics. Muon spin relaxation is caused by the secondary γ-relaxation process, which involves motion of the phenyl rings, and is sensitive to the glass transition. The activation energy of the γ-relaxation process in the rubbery state is 0.60(2) eV in the HMW sample and 0.37(3) eV in the LMW sample.
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Affiliation(s)
- Iain McKenzie
- Centre for Molecular and Material Science, TRIUMF, Vancouver, BC V6T 2A3, Canada
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Department of Physics, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | | | - Joseph Cannon
- School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA, United Kingdom
| | - Stephen P Cottrell
- ISIS, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, United Kingdom
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Samedov K, West R, Percival PW, Brodovitch JC, Chandrasena L, Mozafari M, Tacke R, Junold K, Kobelt C, Samuel PP, Azhakar R, Mondal KC, Roesky HW, Driess M, Wang W. Free Radicals of N-Donor-Stabilized Silicon(II) Compounds Probed by Muon Spin Spectroscopy. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00324] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kerim Samedov
- Organosilicon
Research Center, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Robert West
- Organosilicon
Research Center, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Paul W. Percival
- Department
of Chemistry and TRIUMF, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Jean-Claude Brodovitch
- Department
of Chemistry and TRIUMF, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Lalangi Chandrasena
- Department
of Chemistry and TRIUMF, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Mina Mozafari
- Department
of Chemistry and TRIUMF, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Reinhold Tacke
- Universität Würzburg, Institut für Anorganische
Chemie, Am Hubland, 97074 Würzburg, Germany
| | - Konstantin Junold
- Universität Würzburg, Institut für Anorganische
Chemie, Am Hubland, 97074 Würzburg, Germany
| | - Claudia Kobelt
- Universität Würzburg, Institut für Anorganische
Chemie, Am Hubland, 97074 Würzburg, Germany
| | - Prinson P. Samuel
- Institut
für Anorganische Chemie der Universität Göttingen, Tammannstrasse
4, 37077 Göttingen, Germany
| | - Ramachandran Azhakar
- Institut
für Anorganische Chemie der Universität Göttingen, Tammannstrasse
4, 37077 Göttingen, Germany
| | - Kartik Chandra Mondal
- Institut
für Anorganische Chemie der Universität Göttingen, Tammannstrasse
4, 37077 Göttingen, Germany
| | - Herbert W. Roesky
- Institut
für Anorganische Chemie der Universität Göttingen, Tammannstrasse
4, 37077 Göttingen, Germany
| | - Matthias Driess
- Institute
of Chemistry: Metalorganics and Inorganic Materials, Technische Universität Berlin, Strasse des 17. Juni 135, Sekr. C2, D-10623 Berlin, Germany
| | - Wenyuan Wang
- Institute
of Chemistry: Metalorganics and Inorganic Materials, Technische Universität Berlin, Strasse des 17. Juni 135, Sekr. C2, D-10623 Berlin, Germany
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McKenzie I. The positive muon and μSR spectroscopy: powerful tools for investigating the structure and dynamics of free radicals and spin probes in complex systems. ACTA ACUST UNITED AC 2013. [DOI: 10.1039/c3pc90005c] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ghandi K, McFadden RML, Cormier PJ, Satija P, Smith M. Radical kinetics in sub- and supercritical carbon dioxide: thermodynamic rate tuning. Phys Chem Chem Phys 2012; 14:8502-5. [DOI: 10.1039/c2cp41170a] [Citation(s) in RCA: 8] [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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Fleming DG, Cottrell SP, McKenzie I, Macrae RM. New results for the formation of a muoniated radical in the Mu + Br2 system: a van der Waals complex or evidence for vibrational bonding in Br–Mu–Br? Phys Chem Chem Phys 2012; 14:10953-66. [DOI: 10.1039/c2cp41366c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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