4-Chloro-3,5-dinitrobenzoic acid (1a) and 2-chloro-3,5-dinitrobenzoic acid (1b) were converted into the corresponding acid chlorides (2a and 2b) and these were reacted first with an equimolar amount of 4-amino-2,2,6,6-tetramethylpiperidine-N-oxyl radical (4-amino-TEMPO) to afford monoradicals 3a, 3b, 5a, and 5b and then either (i) with methoxyamine to yield hetero-diradicals 6a and 6b, or (ii) with a second mole of 4-amino-TEMPO to afford homo-diradicals 4a and 4b. The reaction of 3a with 1,3-bis(aminooxy)propane gave the homo-diradical 7a. These reaction products are stable mono-or di-radicals as evidenced by their ESR spectra at various temperatures. The above reaction products can participate as oxidizers in redox reactions, and they afford deep-colored anions with inorganic or organic bases.Keywords: Dinitrobenzamido-TEMPO derivatives, mono-and diradicals (homo-and heterodiradicals), paramagnetic-chromogenic derivatives, RES, oxidizing properties
Four new derivatives of benzo-15-crown-5 (4 -7) were synthesized from 4'-amino-benzo-15-crown-5 (3) and 2-chloro-3,5-dinitrobenzoic acid (1) or its chloride (2): the amide 4 resulted from 2 and 3, and the arylamine 5 from 1 and 3. A compound with two crown ether cavities (6) resulted from 3 and 4. Nucleophilic substitution with methoxyamine converted 4 into 7. Structures were confirmed by 1 H-NMR, 13 C-NMR, and IR-ATR spectroscopy. Geometries of the the new compounds are presented. The hydrophobic character of 5, 6, and 7 was measured by reverse-phase thin-layer chromatography (RP-TLC). The yellow-orange compound 7, in the solid state and in acetonitrile solution becomes deeper-colored in the presence of solid lithium or sodium hydroxides. Stability constants of the corresponding supramolecular complexes 8 (from 7 with LiOH or NaOH) were determined. The supramolecular complex 8 (with Na + ) was also obtained in solid state and was characterized by 1 NMR, IR-ATR and UV-vis spectroscopy.
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