Nitronyl nitroxide radicals

Spin density in interacting nitronyl nitroxide radicals... 

In the first case, ID materials exhibit a peculiar magnetic behaviour only in a restricted class of compounds comprising nitronyl-nitroxide radicals. Much richer is the literature on anisotropic 4f ions showing slow relaxation of the magnetization due to SCM behaviour. 

Figure 5.11. TMAFM image of a thin film (thickness 1 am) of a -/7-NPNN on NaCl(lOO) 1 am x 1 am. Reprinted from Surface Science, Vol. 415, J. Fraxedas, J. Caro, A. Figueras, R Gorostiza andF. SsLnz,Dislocationhollow cores observedon surfaces of molecular organic thin films p-nitrophenyl nitronyl nitroxide radical, 241-250, Copyright (1998), with permission from Elsevier.

The first experimental confirmation of Glauber s prediction was shown with the material Co(hfac)2(NITPhOMe), based on a nitronyl nitroxide radical (Caneschi et al, 2001). Co(hfac)2(NITPhOMe) consists of alternating Co(hfac)2 and radical moieties arranged in ID arrays with a helical structure, and crystallizes in the P3i space group with a = b = 1.129 nm and c = 2.057 nm. A detail of the chain structure is depicted in Fig. 6.21. 

Fig. 5.2 Oxidation by TPAP of dihydroxyimidazolidines to nitronyl nitroxide radicals [30]...

Chains. A critical review of the extrinsic effects, e.g. shape-dependent and propagation phenomena, that may affect the interpretation of the HFEPR of ID materials64 analysed data from the molecular-based system made up of Gd3+ ions and the nitronyl-nitroxide radicals (NIT-Et = 2- ethyl-4,4,5,5,-tetramethyl-... 

The synthesis was performed according to Scheme 9.9. Compound 20a was synthesized from 1,2-bis(3,4-dimethyl-2-thienyl)hexafluorocyclopentene (21). After iodination, the transformation to diboronic acid followed by Suzuki coupling with 4-formyl-4 -iodobiphenyl gave diformyl compound 23a. The conventional treatment was employed for formyl compounds 23a to convert nitronyl nitroxide radical 20a. 

Nitronyl nitroxide radical Imino nitroxide radical 3,5- Bu-sonoquinonato... 

Figure 9.2 The radical structure of nitronyl nitroxide radical, imino nitroxide radical, and semo-quinonato.

Figure 9.7 The structure of NITR radical and the schematic view of the crystal structure of RE(hfac)3NITEt [76], (Reprinted from A. Caneschi, D. Gatteschi, and R. Sessoli, Magnetic properties of a layered molecular material comprising manganese hexafluoroacetylacetonate and nitronyl nitroxide radicals, Inorganic Chemistry 32, 4612 616, 1993. 1993 American Chemical Society.)...

Benelli, C., Caneschi, A., Fabretti, A.C., Gatteschi, D., and Pardi, L. (1990) Ferromagnetic couphng of gadolinium(lll) ions and nitronyl nitroxide radicals in an essentially isotropic way. Inorganic Chemistry, 29, 4153-4155. 

Luneau, D. and Rey, P. (1995) New manganese(II) complexes of nitronyl nitroxide radicals. Synthesis, structure and magnetic properties. Molecular Crystals and Liquid Crystals Science and Technology Section A, 273, 81-87. 

Tamura, M., Nakazawa, Y., Shiomi, D., Nozawa, K., Hosokoshi, Y, Ishikawa, M., Takahashi, M. and Kinoshita, M. (1991). Bulk ferromagnetism in the /3-phase crystal of the / -nitrophenyl nitronyl nitroxide radical. Chem. Phys. Lett., 186, 401. [201]... 

Veciana, J., Cirujeda, J., Rovira, C., Molins, E. andNovoa, J. J. (1996). Organic ferro-magnets. Hydrogen bonded supramolecular magnetic organizations derived from hydroxylated phenyl a-nitronyl nitroxide radicals. J. Phys. I Ft, 6, 1967-86. [201] Venkatesan, K. and Ramamurthy, V. (1991). Bimolecular photoreactions in crystals. In Photochemistry in organized and constrained media (ed. V. Ramamurthy), pp. 133-84. VCH Publishers, Weinheim. [236]... 

The imino nitroxide radicals (201) exhibit a similar spin distribution to that of the nitronyl nitroxide radicals. The methyl protons on the two sides of the imino nitroxide ring are found to have different coupling constants. This is thought to be due either to different relative geometries or to an interaction between the methyl protons on the... 

Upon irradiation with a Xe lamp (100 W), the typical five-line spectrum characteristic of the nitronyl nitroxide radical 114 (g= 2.0066) was progressively transformed into a seven-line spectrum characteristic of an imino nitroxide radical (Scheme 24). It was proposed that during the irradiation, selective deoxygenation of the radical 114 to the radical 115 had occurred <2003S2145>. 

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