The diorganoselenides [2-(R2NCH2)C6H4](pzCH2CH2)Se [R = Me (1), Et (2), R2 = O(CH2CH2)2 (3); pz = pyrazole] and [2-{(CH2O)2CH}C6H4](pzCH2CH2) Se (4) were prepared by reacting pzCH2CH2Br with the corresponding alkali metal organoselenolate. Compound [2-(O=CH)C6H4](pzCH2CH2)Se (5) was obtained by deprotection of compound 4 under acidic conditions, whereas compound (pzCH2CH2)2Se (6) was prepared by reacting pzCH2CH2Br with Na2Se. The antioxidant activity of compounds 1–3 and 6 in the catalytic reac- tion between H2O2 and PhSH was investigated by a combination of experimen- tal methods (multinuclear NMR, UV-vis spectroscopy, cyclic voltammetry) and theoretical calculations. The formation of the intermediate selenoxide species 1a–6a was evidenced by multinuclear NMR experiments (1H, 13C{1H}, 77Se {1H}) that revealed the existence of intramolecular N!Se interactions. Density functional theory (DFT) calculations showed that these interactions are mostly covalent in nature. For compound 1, an autocatalytic mechanism is proposed.

Homoleptic and heteroleptic diorganoselenides containing pyrazole functionalities. Synthesis, characterization, and antioxidant activity

Arca, Massimiliano;Lippolis, Vito;Pintus, Anna
;
2022-01-01

Abstract

The diorganoselenides [2-(R2NCH2)C6H4](pzCH2CH2)Se [R = Me (1), Et (2), R2 = O(CH2CH2)2 (3); pz = pyrazole] and [2-{(CH2O)2CH}C6H4](pzCH2CH2) Se (4) were prepared by reacting pzCH2CH2Br with the corresponding alkali metal organoselenolate. Compound [2-(O=CH)C6H4](pzCH2CH2)Se (5) was obtained by deprotection of compound 4 under acidic conditions, whereas compound (pzCH2CH2)2Se (6) was prepared by reacting pzCH2CH2Br with Na2Se. The antioxidant activity of compounds 1–3 and 6 in the catalytic reac- tion between H2O2 and PhSH was investigated by a combination of experimen- tal methods (multinuclear NMR, UV-vis spectroscopy, cyclic voltammetry) and theoretical calculations. The formation of the intermediate selenoxide species 1a–6a was evidenced by multinuclear NMR experiments (1H, 13C{1H}, 77Se {1H}) that revealed the existence of intramolecular N!Se interactions. Density functional theory (DFT) calculations showed that these interactions are mostly covalent in nature. For compound 1, an autocatalytic mechanism is proposed.
2022
antioxidant activity; DFT calculations; diorganoselenides; diorganoselenoxides; NMR studies
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11584/344734
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