Metal-nitroxyl interactions. 25. Exchange interactions via saturated linkages in spin-labeled porphyrins

1982 ◽  
Vol 60 (12) ◽  
pp. 1392-1401 ◽  
Author(s):  
Kundalika M. More ◽  
Gareth R. Eaton ◽  
Sandra S. Eaton
Keyword(s):  
Electron Spin ◽  
Room Temperature ◽  
Pyrrole Ring ◽  
Variable Temperature ◽  
Exchange Interactions ◽  
Spin Coupling ◽  
Epr Spectra ◽  
Coupling Constant ◽  
Acrylic Ester ◽  
Cis And Trans

A series of spin-labeled copper porphyrins has been prepared in which nitroxyl radicals are attached to a porphyrin pyrrole ring by propionamide and propionate ester linkages. The solution epr spectra at room temperature indicate that the values of the electron spin – electron spin coupling constant, J, for these compounds are in the range 4 to 18 G, depending on the solvent and the size of the nitroxyl ring. Below −45 °C two isomers with different values of J were observed in the epr spectra of two of the compounds. Variable temperature epr spectra were also analyzed for analogous spin-labeled copper porphyrins which have cis and trans acrylic ester and acrylamide linkages between the porphyrin and the nitroxyl ring. Comparison of the values of J for the complexes with saturated and unsaturated linkages suggests that σ-bonding pathways dominate the copper–nitroxyl interaction in these compounds.

Assignment of cis-trans Geometry in Diastereomeric 2-Benzyl-4-methyl-1,3,2-dioxaphosphorinans and their 2-Oxo- and 2-Seleno-Derivatives

1975 ◽  
Vol 30 (9-10) ◽  
pp. 710-715 ◽  
Author(s):  
W. J. Stec ◽  
K. Lesiak ◽  
D. Mielczarek ◽  
B. Stec
Keyword(s):  
Nmr Spectroscopy ◽  
Spin Coupling ◽  
Coupling Constant ◽  
Spin Coupling Constant ◽  
Geometrical Isomers ◽  
Benzyl Halides ◽  
New Compounds ◽  
Cis And Trans ◽  
Spin Spin Coupling ◽  
C Nmr

MICHAELIS-ARBUSOV reaction of diastereoisomeric 2-methoxy-4-methyl-1,3,2-dioxaphosphorinans with benzyl halides is non-stereospecific. Cis- and trans-2-benzyl-2-oxo-4-methyl-1,3,2-dioxaphosphorinans were separated and analysed by means of IR, 31P and 13C NMR spectroscopy. 2-Benzyl-2-seleno-4-methyl-1,3,2-dioxaphosphorinans were synthesized and stereospecifically converted to 2-oxo-analogues. Stereochemistries are assigned to the geometrical isomers of all new compounds described in this paper. Application of direct spin-spin coupling constant values for structural elucidation is emphasized.

Unusually large hyperfine structure of the electron spin levels in an endohedral dimetallofullerene and its spin coherent properties

Nanoscale ◽  
2020 ◽  
Vol 12 (39) ◽  
pp. 20513-20521
Author(s):  
Ruslan B. Zaripov ◽  
Yuri E. Kandrashkin ◽  
Kev M. Salikhov ◽  
Bernd Büchner ◽  
Fupin Liu ◽  
...  
Keyword(s):  
Hyperfine Structure ◽  
Electron Spin ◽  
Hyperfine Coupling ◽  
Hyperfine Coupling Constant ◽  
Broad Temperature Range ◽  
Epr Spectra ◽  
Coupling Constant ◽  
Spin Coherence ◽  
Temperature Range

Sc2@C80(CH2Ph) with giant 45Sc hyperfine coupling constant yields fully-resolved EPR spectra and maintains spin coherence in a broad temperature range.

An electron spin resonance study of (N-2-Pyridylsalicylaldiminato)copper(II) nitrate

1975 ◽  
Vol 28 (6) ◽  
pp. 1211 ◽  
Author(s):  
TD Smith ◽  
DJ Cookson ◽  
JR Pilbrow ◽  
R Beckett
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Exchange Interactions ◽  
Electron Spin Resonance Study ◽  
Magnetic Exchange ◽  
Spin Resonance ◽  
Dimeric Form ◽  
Spin Resonance Study

The magnetic susceptibility of (N-2-pyridylsalicylaldiminato)copper(II) nitrate and chloride has been measured at room temperature and 97 K. Contrary to results reported previously we find no evidence for the presence of magnetic exchange interactions in these compounds. Electron spin resonance spectral data on the ethanol-dimethylformamide solutions of the chelates show that the chelates are monomeric in the liquid phase but largely in dimeric form in frozen solution. Computer simulation of the experimental e.s.r. spectra due to the dimeric form has enabled a determination of the symmetry arrangement and structural properties of the pair system to be made.

scholarly journals EPR Spectra of Sintered Cd1−xCrxTe Powdered Crystals with Various Cr Content

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3449
Author(s):  
Ireneusz Stefaniuk ◽  
Werner Obermayr ◽  
Volodymyr D. Popovych ◽  
Bogumił Cieniek ◽  
Iwona Rogalska
Keyword(s):  
Curie Temperature ◽  
Room Temperature ◽  
Integral Intensity ◽  
Resonance Field ◽  
Epr Spectra ◽  
Paramagnetic Resonance ◽  
Simple Method ◽  
Paramagnetic Curie Temperature ◽  
Cr Content ◽  
Electron Paramagnetic

In this paper, we show a simple method of producing ferromagnetic materials with a Curie temperature above room temperature. The electron paramagnetic resonance (EPR) spectra of Cd1−xCrxTe (0.002 < x < 0.08) were measured with a dependence on temperature (82 K < T < 381 K). Obtained EPR lines were fitted to a Lorentz-shaped curve. The temperature dependencies of the parameters of the EPR lines, such as the peak-to-peak linewidth (Hpp), the intensity (A), as well as the resonance field (Hr), were studied. Ferromagnetism was noticed in samples at high temperatures (near room temperature). For a sample with a nominal concentration of chrome of x = 0.05, a very strong intrinsic magnetic field is observed. The value of the effective gyromagnetic factor for this sample is ge = 30 at T = 240 K. An increase of chrome concentration above x = 0.05 reduces the ferromagnetic properties considerably. Analysis of the temperature dependencies of the integral intensity of EPR spectra was carried out using the Curie–Weiss law and the paramagnetic Curie temperature was obtained.

scholarly journals Force detection of high-frequency electron spin resonance near room temperature using high-power millimeter-wave source gyrotron

2021 ◽  
Vol 118 (2) ◽  
pp. 022407
Author(s):  
Hideyuki Takahashi ◽  
Yuya Ishikawa ◽  
Tsubasa Okamoto ◽  
Daiki Hachiya ◽  
Kazuki Dono ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Millimeter Wave ◽  
Electron Spin ◽  
High Power ◽  
High Frequency ◽  
Room Temperature ◽  
Force Detection ◽  
Wave Source ◽  
Spin Resonance ◽  
Millimeter Wave Source

An estimate of the spin–spin coupling constant, 1J(1H,13C), in gaseous benzene

1996 ◽  
Vol 74 (8) ◽  
pp. 1524-1525 ◽  
Author(s):  
Ted Schaefer ◽  
Guy M. Bernard ◽  
Frank E. Hruska
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Dielectric Constant ◽  
Magnetic Resonance ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Coupling Constant ◽  
Spin Coupling Constant ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Gaseous Benzene

An excellent linear correlation (r = 0.9999) exists between the spin–spin coupling constants 1J(1H,13C), in benzene dissolved in four solvents (R. Laatikainen et al. J. Am. Chem. Soc. 117, 11006 (1995)) and Ando's solvation dielectric function, ε/(ε – 1). The solvents are cyclohexane, carbon disulfide, pyridine, and acetone. 1J(1H,13C)for gaseous benzene is predicted to be 156.99(2) Hz at 300 K. Key words: spin–spin coupling constants, 1J(1H,13C) for benzene in the vapor phase; spin–spin coupling constants, solvent dielectric constant dependence of 1J(1H,13C) in benzene; benzene, estimate of 1J(1H,13C) in the vapor; nuclear magnetic resonance, estimate of 1J(1H,13C) in gaseous benzene.

Internal motion in benzylidene diacetate and its 2,6-dibromo derivative by DNMR and the J method

1989 ◽  
Vol 67 (6) ◽  
pp. 1022-1026 ◽  
Author(s):  
Ted Schaefer ◽  
Craig S. Takeguchi
Keyword(s):  
Double Resonance ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Maximum Magnitude ◽  
Coupling Constant ◽  
Spectral Parameters ◽  
Proton Proton ◽  
Ether Solution ◽  
Spin Spin Coupling ◽  
Dibromo Derivative

The 1H nuclear magnetic resonance spectral parameters are reported for benzylidene diacetate in CS2 and acetone-d6 solutions. The long-range spin–spin coupling constant over six formal bonds, 6J, is used to derive apparent twofold barriers to rotation about the exocyclic C(1)—C bond in the two solutions. The conformation of lowest energy has the α. C—H bond in the benzene plane. The barrier is higher in CS2 than in acetone-d6 solution, in contrast to a molecule like benzyl chloride. In the 2,6-dibromo derivative, the free energy of activation for reorientation about the bond in question is 36 kJ/mol at 165 K in dimethyl ether solution. Such a high barrier implies a very small six-bond proton–proton coupling constant for this derivative because 6J is proportional to the expectation value of sin2θ. The angle θ is zero when the α C—H bond lies in the benzene plane. 6J is −0.051 Hz in acetone-d6 solutions; its sign is determined by double resonance experiments. The question of an angle-independent component of 6J, that is, whether 6J is finite at θ = 0°, is addressed. A maximum magnitude of 0.02 Hz may be present at θ = 0° for the 2,6-dibromo derivative, although a zero magnitude is also compatible with the experimental data. In a compound with a higher internal barrier, α,α,2,6-tetrachlorotoluene, the experimental results are best in accord with a negligibly small 6J at θ = 0°. Keywords: 1H NMR of benzylidene diacetate, spin–spin coupling constants for benzylidene diacetate, DNMR, 2,6-dibromobenzylidene diacetate.

Long room-temperature electron spin lifetimes in highly doped cubic GaN

2010 ◽  
Vol 97 (6) ◽  
pp. 062101 ◽  
Author(s):  
J. H. Buß ◽  
J. Rudolph ◽  
T. Schupp ◽  
D. J. As ◽  
K. Lischka ◽  
...  
Keyword(s):  
Electron Spin ◽  
Room Temperature ◽  
Cubic Gan ◽  
Temperature Electron
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