title: Preparation and spectroscopic, magnetic, and electrochemical studies of mono-/biradical TEMPO derivatives.
abstract: A comparison set of mono-/biradical TEMPO derivatives was prepared, novel compounds were fully characterized, and their physicochemical properties were determined. Cyclic voltammetry revealed reversible redox behavior for all studied nitroxides. Moreover, the electron-withdrawing substituents increased the oxidation potential of the respective nitroxides in comparison to electron-donating groups. While EPR spectra of monoradicals in dichloromethane at 295 K reveal the expected three-line signal, spectra of biradicals show more complex features. DFT and MP2 calculations indicate that the EPR splitting pattern of dinitroxide 7 could be explained by its interactions with solvent molecules. In the solid state, mononitroxides 4 and 5 behave as a Heisenberg antiferromagnetic chain, whereas dinitroxides 6-8 are almost isolated paramagnetic diradicals coupled in an antiferromagnetic manner.
authors.affiliation: Department of Organic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37 Bratislava, Slovakia.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Kavala
authors.forename: Roman
authors.initials: R
authors.lastname: Boča
authors.forename: Lubomír
authors.initials: L
authors.lastname: Dlháň
authors.forename: Vlasta
authors.initials: V
authors.lastname: Brezová
authors.forename: Martin
authors.initials: M
authors.lastname: Breza
authors.forename: Jozef
authors.initials: J
authors.lastname: Kožíšek
authors.forename: Marek
authors.initials: M
authors.lastname: Fronc
authors.forename: Peter
authors.initials: P
authors.lastname: Herich
authors.forename: Lubomír
authors.initials: L
authors.lastname: Švorc
authors.forename: Peter
authors.initials: P
authors.lastname: Szolcsányi
mesh_terms: D018360:Crystallography, X-Ray; D003497:Cyclic N-Oxides / Q000138:chemical synthesis* / Q000737:chemistry*; D055664:Electrochemical Techniques; D004578:Electron Spin Resonance Spectroscopy; D060526:Magnetic Fields; D008958:Models, Molecular; D015394:Molecular Structure; D011789:Quantum Theory
chemical_list: D003497:Cyclic N-Oxides; C003959:TEMPO