4567-18-4Relevant articles and documents
Synthesis and Magnetic Properties of (Pyrrolidin-1-oxyl)–(Nitronyl Nitroxide)/(Iminonitroxide)-Dyads
Tsujimoto, Haruki,Suzuki, Shuichi,Kozaki, Masatoshi,Shiomi, Daisuke,Sato, Kazunobu,Takui, Takeji,Okada, Keiji
, p. 1801 - 1806 (2019)
Unlike extensively studied diradicals linked by π-conjugated systems, only a few studies have investigated weakly coupled diradicals linked by an sp3 carbon atom. Herein, we prepared pyrrolidin-1-oxyl–(nitronyl nitroxide)-dyad 5 and pyrrolidin-1-oxyl–iminonitroxide-dyad 6. From the observed temperature dependence of the magnetic susceptibility, 5 and 6 were determined to be in singlet ground states with 2Jintra/kB=?35.2 K and ?13.6 K, respectively. From these results and theoretical calculations of related diradicals, the spin-polarization model counting the small spin density of the sp3 carbon atom could be used as a spin-prediction model.
Electrochemical and esr spin trap studies of a new iron tetra- catecholamide complex
Cheraiti,Brik,Keita,Nadjo,Gaudemer
, p. 2315 - 2320 (1999)
A new siderophore, N5,N6-thiodipropanoyl-bis[N1,N10-bis(2,3-dihydroxy benzoyl-spermidine)]-Fe (III) complex or H2LFe has been synthesised. The reaction of the reduced form of this complex with dioxygen has been investigated through electrochemical study and revealed the formation of a new species assumed to be H2O2. This species has been confirmed by esr spectroscopy using the diamagnetic compound 5-deutero-2,2,5- trimethylpyrrolidine-1-hydroxyl as spin trap. The resulting persistent radical is 5-deutero-2,2,5-trimethylpyrrolidine-1-yloxy (a(N) = 16.58 G, a(D) = 3.49 G).
New 2-Substituted Pyrroline-N-oxides: An EPR Solvent Study of the Radical Spin Adducts
Janzen, Edward G.,Zhang, Yong-Kang,Haire, D. Lawrence
, p. 711 - 720 (2007/10/02)
Ten substituted 5,5-dimethyl-1-pyrroline-N-oxides as well as the parent nitrene spin trap (DMPO) were prepared: 5,5-dimethyl-1-pyrroline-N-oxide, 2,5,5-trimethyl-1-pyrroline-N-oxide, 2-tert-butyl-5,5-dimethyl-1-pyrroline-N-oxide, 2-phenyl-5,5-dimethyl-1-pyrroline-N-oxide, 2-d5-phenyl-5,5-dimethyl-1-pyrroline-N-oxide, 2-phenyl-5,5-dimethyl-1-pyrroline-N-oxide-nitronyl-13C, 2-(4-fluorophenyl)-5,5-dimethyl-1-pyrroline-N-oxide, 2-(4-chlorophenyl)-5,5-dimethyl-1-pyrroline-N-oxide, 2-(4-tert-butylphenyl)-5,5-dimethyl-1-pyrroline-N-oxide, 2-(4-methylphenyl)-5,5-dimethyl-1-pyrroline-N-oxide and 2-(2-methylphenyl)-5,5-dimethyl-1-pyrroline-N-oxide.Analytical (i.e.EPR-grade) samples of these novel cyclic nitrones were obtained and characterized by (among other methods) 1H NMR spectroscopy.Reduction of DMPO and these various 2-substituted cyclic nitrones gave the corresponding cyclic N,N-dialkylhydroxylamines, whose structure and conformations were also analyzed by 1H NMR spectroscopy.Air oxidation of these cyclic N,N-dialkylhydroxylamines provided access to the EPR spectra of the hydrogen, methyl, tert-butyl, phenyl, d5-phenyl, nitronyl-13C-phenyl, 4-fluorophenyl, 4-chlorophenyl, 4-tert-butylphenyl, 4-methylphenyl and 2-methylphenyl cyclic aminoxyl (pyrrolidine N-oxyl nitroxide) radical spin adducts of DMPO.The 14N, 13C (where applicable) and 1H hyperfine splitting constants of these aminoxyl adducts in ten solvents of widely different polarities (e.g., hexane to water) were measured and the solvent effect on these parameters was evaluated.It was found that for the various 2-substituted DMPO-type apin adducts both the nitrogen and β-hydrogen EPR hyperfine splittings correlated linearly (r2 >/= 0.90) with typical solvent polarity parameters such as ET(30).The correlation between the nitrogen and β-hydrogen hyperfine splitting constants were even more linear (r2 >/= 0.97). - Keywords: electron paramagnetic resonance NMR 1H, 14N and 13C hyperfine splittings Spin traps Spin adducts Nitrones (1-pyrroline-N-oxides)