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Polyradical PROXYL/TEMPO‐Derived Amides: Synthesis, Physicochemical Studies, DFT Calculations, and Antimicrobial Activity
Author(s) -
Poprac Patrik,
Poliak Peter,
Kavala Miroslav,
Barbieriková Zuzana,
Zalibera Michal,
Fronc Marek,
Švorc Ľubomír,
Vihonská Zuzana,
Olejníková Petra,
Lušpai Karol,
Lukeš Vladimír,
Brezová Vlasta,
Szolcsányi Peter
Publication year - 2017
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201700343
Subject(s) - electron paramagnetic resonance , chemistry , cyclic voltammetry , intramolecular force , paramagnetism , spin probe , electrochemistry , spectral line , computational chemistry , organic chemistry , nuclear magnetic resonance , condensed matter physics , physics , electrode , astronomy
A series of polynitroxide amides possessing 2,2,5,5‐tetramethyl‐1‐pyrrolidinyloxy (PROXYL) and/or 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO) units connected through various bridges were synthesized and their properties were analyzed. EPR spectroscopy provided detailed insight into their paramagnetic character and related properties. A thorough examination of the EPR spectra of dinitroxides in organic solvents provided valuable information on the intramolecular motions, thermodynamics, and spin‐exchange mechanisms. Analysis of low‐temperature X‐ and Q‐band EPR spectra of the dissolved dinitroxides provided spin–spin distances that were comparable with the theoretical values obtained by DFT. Cyclic voltammetry investigations revealed (quasi)reversible electrochemical behavior for PROXYL‐derived biradicals, whereas significant loss of the reversibility was found for TEMPO‐containing bi‐ and polyradicals. The inhibitory activities of the nitroxides against model bacteria, yeasts, and filamentous fungi were assessed.