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Abstract
Antioxidant activity of organoselenium compounds belonging to different classes i.e. functionalized aliphatic, aromatic and cyclic selenoethers, are compared on the basis of their ability to scavenge reactive oxygen species like hydroxyl and peroxyl radicals and to exhibit glutathione peroxidase (GPx) like catalytic activity. The comparative analysis has revealed that the antioxidant activity of the organoselenium compounds show direct correlation with the energy of the highest occupied molecular orbital (HOMO) and neighboring group participation that stabilizes the reaction intermediate. Finally, structural features responsible for improving the rate of reaction of organoselenium compounds with free radical/molecular oxidants have been discussed on the basis of the compounds screened at our institute.
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Affiliation(s)
- Beena G Singh
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai, India.,Homi Bhabha National Institute, Mumbai, India
| | - Amit Kunwar
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai, India.,Homi Bhabha National Institute, Mumbai, India
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Satake A, Suzuki Y, Sugimoto M, Shimazaki T, Ishii H, Kuramochi Y. A Solvation/Desolvation Indicator Based on van der Waals Interactions between Solvents and Porphyrins. Chemistry 2018; 24:14733-14741. [PMID: 29989274 DOI: 10.1002/chem.201802402] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 06/26/2018] [Indexed: 12/16/2022]
Abstract
Solvation is a ubiquitous phenomenon associated with molecules in solutions. It often determines the equilibria of molecular systems and the rates of chemical reactions. Van der Waals interactions (a general term) includes weak interactions among noncharged compounds and it contributes significantly to solvation. The distinct observation of van der Waals interaction between solvent and porphyrin derivatives is reported herein. Bis(imidazolylporphyrinatozinc) structures connected through a 1,3-butadiyne moiety give two types of coordination polymers, E (extended) and S (stacked) polymers, exclusively. E polymers have larger solvent-accessible surface areas than the corresponding S polymers. Therefore, E polymers are better solvated than S polymers, providing an indicator of solvation and desolvation for the solvents used. A simple method (like a litmus test) was developed to evaluate the solvation ability of various solvents. Sixty-seven solvents and liquid compounds were tested, under the same conditions, using a conventional UV/Vis spectrometer. The results revealed a new liquid group with high solvation ability towards the porphyrins, and clarified van der Waals interaction assisted by secondary interaction on the substituents. The indicator system should contribute to the solution chemistry of molecules and materials, and to supramolecular chemistry interactions among hetero components.
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Affiliation(s)
- Akiharu Satake
- Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan.,Department of Chemistry, Faculty of Science Division II, Tokyo University of Science, Japan
| | - Yuki Suzuki
- Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Motonobu Sugimoto
- Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Tatsumi Shimazaki
- Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Hidekazu Ishii
- Department of Chemistry, Faculty of Science Division II, Tokyo University of Science, Japan
| | - Yusuke Kuramochi
- Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan.,Department of Chemistry, Faculty of Science Division II, Tokyo University of Science, Japan
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Gou Q, Spada L, Vallejo-López M, Kisiel Z, Caminati W. Interactions between freons: a rotational study of CH₂F₂-CH₂Cl₂. Chem Asian J 2014; 9:1032-8. [PMID: 24573907 DOI: 10.1002/asia.201301722] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 01/21/2014] [Indexed: 11/06/2022]
Abstract
The rotational spectra of two isotopologues of a 1:1 difluoromethane-dichloromethane complex have been investigated by pulsed-jet Fourier-transform microwave spectroscopy. The assigned (most stable) isomer has C(s) symmetry and it displays a network of two C-H⋅⋅⋅Cl-C and one C-H⋅⋅⋅F-C weak hydrogen bonds, thus suggesting that the former interactions are stronger. The hyperfine structures owing to (35)Cl (or (37)Cl) quadrupolar effects have been fully resolved, thus leading to an accurate determination of the three diagonal (χ(gg); g=a, b, c) and the three mixed quadrupole coupling constants (χ(gg'); g, g'=a, b, c; g≠g'). Information on the structural parameters of the hydrogen bonds has been obtained. The dissociation energy of the complex has been estimated to be 7.6 kJ mol(-1).
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Affiliation(s)
- Qian Gou
- Dipartimento di Chimica "G. Ciamician", Università di Bologna, Via Selmi 2, I-40126 Bologna (Italy), Fax: (+39) 0512099456
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