Synthesis, crystal structure and magnetic properties of a novel nitroxide biradical. Theoretical investigation of the exchange mechanisms

Fritscher, Jörg; Beyer, Mario; Schiemann, Olav

doi:10.1016/s0009-2614(02)01344-1

Cited by 32 publications

(33 citation statements)

References 26 publications

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“…The residual Lorentzian line width is 0.3 MHz and an axial diffusion tensor with D xy = 1 GHz and D zz = 100 GHz was assumed. All values are in good agreement with literature values [27,37]. The low temperature spectrum of the copper(II) centre has been simulated using g xx = g yy = 2.047, g zz = 2.17 and a g-strain of g xx = g yy = 0.005, g zz = 0.015 and A xx = A yy = 3 mT, A zz = 21 mT for the Cu hyperfine coupling.…”

Section: Epr Measurementssupporting

confidence: 87%

“…It is, however, mandatory, that the spin-spin coupling tensor is smaller than the excitation band width of the pulses, which limits the method to small exchange couplings and rather long distances. Thus, PELDOR complements nicely other methods capable to measure J: Large exchange coupling constants can be determined with their sign via temperature dependent Squid measurements [26] or via temperature dependent measurements of the intensity of the half-field EPR signal [27]. Exchange coupling constants on the order of the hyperfine coupling can be obtained via simulations of the isotropic main field EPR signal but without sign [28] and small exchange coupling constants are accessible from PELDOR spectra.…”

Section: Resultsmentioning

confidence: 98%

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PELDOR on an exchange coupled nitroxide copper(II) spin pair

Bode

Plackmeyer

Bolte

et al. 2009

Journal of Organometallic Chemistry

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Section: Epr Measurementssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 98%

PELDOR on an exchange coupled nitroxide copper(II) spin pair

Bode

Plackmeyer

Bolte

et al. 2009

Journal of Organometallic Chemistry

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“…Numerous nitroxide biradicals are known nowadays ( [1][2][3][4][5][6][7][8][9] and references therein). Of particular interest are nitroxide biradicals with bridges containing one or several acetylene and other groups with possible high degree of conjugation between two paramagnetic nitroxide centers [10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

EPR, the X-ray Structure and DFT Calculations of the Nitroxide Biradical with One Acetylene Group in the Bridge

et al. 2014

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Two short nitroxide biradicals of similar composition, R6 0 -R6 0 (B0) and R6 0 -(C : C)-R6 0 (B1), where R6 0 is 1-oxyl-2,2,6,6-tetramethyl-3,4-ene-nitroxide ring, have been investigated by electron paramagnetic resonance spectroscopy and X-ray structural analysis. Quantum chemical calculations at UDFT/B3LYP/ccpVDZ level were also performed and compared with the X-ray structural data. Zerofield splitting parameters D for B0 and B1 were found to be equal -0.0048 and -0.0022 cm -1 , respectively, in good agreement with quantum chemical prediction. Potential energy surface scans corresponding to pathways of the conformational rearrangements were calculated; rotation barriers for B0 and B1 were found to be 19.2 and 4.0 kJ/mol, respectively; and structural rigidity and probable differences in biradicals behavior are discussed. Calculations of spin density distribution in biradicals B0 and B1 were also carried out.

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“…Thermal homolysis of Ti-O bonds derived from titanium-TEMPO complex and subsequent ring opening mediated by the Cp 2 Ti(III)Cl complex followed by TEMPO trapping Scheme 5 54. Oxidative coupling of arenes with various arylboronic acids equivalents) of the rhodium(I) complex to the rhodium(III) complex, and can also act as a base through the deprotonated (anionic) form of the corresponding hydroxylamine.…”

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confidence: 99%