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| Format: | Artículo científico |
| Language: | en |
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Sociedad Química de México
2008
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| Online Access: | https://www.redalyc.org/articulo.oa?id=47552108 |
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Table of Contents:
- Synthesis, Structure and Magnetic Differences of Two a-Nitronyl Nitroxide Isomers Araceli Vega Juan Padilla María del Jesús Rosales Marco Antonio Leyva Sylvain Bernès Multidisciplinaria (Ciencias Naturales y Exactas) isomers structure ferromagnetism Organic radicals phase transition The two isomeric organic nitronyl nitroxide free radicals2-(2-hydroxyl-3-methoxy-phenyl)-4, 4, 5, 5-tetramethyl-4, 5-dihydro-1H-imidazoyl-1-oxyl-3-oxide, 1, and 2-(3-hydroxyl-4-methoxyphenyl)-4, 4, 5, 5-tetramethyl-4, 5-dihydro-1H-imidazoyl-1-oxyl-3-oxide, 2, have been synthesized and their structures determined byX-ray diffraction. Structure 1 has three dimensional, strong, intramolecularhydrogen bonds in addition to intermolecular interactionsfavoring sheets. The structure of radical 2 also shows strong hydrogenbonds both intra- and intermolecular. Some of these bonds are with alattice water molecule, yielding a three-dimensional crystal structure.An important structural difference between both radicals is that incompound 1, one of the nitrogen atoms of the radical shows smallerangles than the other atom in the same radical and than both nitrogenatoms in compound 2. This suggests that in 1, one of the nitrogenatoms has a higher sp3 character than the other. This proposal is supportedby the N-O bond length which is significantly longer in the sp3nitrogen side. Both isomers show quite different magnetic behavior.In 1 there are both ferromagnetic (JF/k = + 0.11 ± 0.01 K) and antiferromagnetic(JAF/k = - 0.81 ± 0.10 K) interactions, whereas 2 onlyshows antiferromagnetism (JAF/k = - 1.60 ± 0.02 K) with a phasetransition at Tc = 2.48 K. 2008 artículo científico 1870-249X https://www.redalyc.org/articulo.oa?id=47552108 en http://www.redalyc.org/revista.oa?id=475 Journal of the Mexican Chemical Society application/pdf Sociedad Química de México Journal of the Mexican Chemical Society (México) Num.1 Vol.52