scholarly journals Synthesis and electron paramagnetic resonance studies of chiral spin-labeled crown ethers

1984 ◽  
Vol 62 (3) ◽  
pp. 489-497 ◽  
Author(s):  
H. Dugas ◽  
P. Keroack ◽  
M. Ptak
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Crown Ether ◽  
Crown Ethers ◽  
Spin Interaction ◽  
Ion Binding ◽  
Paramagnetic Resonance ◽  
Dynamical Fluctuation ◽  
Electron Paramagnetic

The synthesis of syn and anti chiral dinitroxide [18]-crown-6 ethers and of a tetranitroxide crown ether is described. The existence of a spin–spin interaction for the syn isomer makes this spin-labeled crown ether probe particularly useful to follow by epr the effects of K+ ion binding, pH, solvent, and temperature. These observations are discussed in terms of a global dynamical fluctuation of the substituted crown ether.

scholarly journals Димерная самоорганизация примесных ионов эрбия в синтетическом форстерите

2019 ◽  
Vol 61 (2) ◽  
pp. 313
Author(s):  
Р.Б. Зарипов ◽  
Л.В. Мингалиева ◽  
В.Ф. Тарасов ◽  
Е.В. Жариков ◽  
К.А. Субботин ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Resonance Method ◽  
Magnetic Characteristics ◽  
Spin Interaction ◽  
Magnesium Ions ◽  
Crystallographic Position ◽  
Paramagnetic Resonance ◽  
Effective Spin ◽  
Erbium Ions ◽  
Electron Paramagnetic

AbstractThe electron paramagnetic resonance spectra of impurity trivalent erbium ions in synthetic forsterite single crystals (Mg_2SiO_4) have been studied by the electron paramagnetic resonance method in the X and Q frequency bands. It is found that erbium ions predominantly substitute for magnesium ions in crystallographic position M1 that is characterized by the inversion symmetry of the crystal field. In this case, a pronounced effect of dimer self-organization of erbium ions during the crystal growth takes place; the effect is manifested in the fact that the concentration of erbium dimer associates consisting of two closely spaced ions bound by the spin– spin interaction is several orders of magnitude higher than the concentration of dimer associates that form randomly at a statistical distribution of impurity ions in the forsterite crystal lattice. The directions of the main magnetic axes and the parameters of the effective spin Hamiltonian describing the magnetic characteristics of impurity erbium centers have been determined.

Redox-active crown ethers. Electrochemical and electron paramagnetic resonance studies on alkali metal complexes of quinone crown ethers

1992 ◽  
Vol 114 (23) ◽  
pp. 8983-8991 ◽  
Author(s):  
Milagros Delgado ◽  
Robert E. Wolf ◽  
JudithAnn R. Hartman ◽  
Gillian McCafferty ◽  
Rahmi Yagbasan ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Alkali Metal ◽  
Metal Complexes ◽  
Crown Ethers ◽  
Paramagnetic Resonance ◽  
Redox Active ◽  
Electron Paramagnetic ◽  
Alkali Metal Complexes
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