The crystal structure of a new phase of the pnitrophenyl nitronyl &oxide radical compound is described. A study of its magnetic properties reveals the largest intermolecular ferromagnetic coupling reported so far among a series of polymorphs of this compound.
Bulk ferromagnetism in the β-phase crystal of the p-nitrophenyl nitronyl nitroxide radical
✍ Scribed by Masafumi Tamura; Yasuhiro Nakazawa; Daisuke Shiomi; Kiyokazu Nozawa; Yuko Hosokoshi; Masayasu Ishikawa; Minuro Takahashi; Minoru Kinoshita
- Publisher
- Elsevier Science
- Year
- 1991
- Tongue
- English
- Weight
- 334 KB
- Volume
- 186
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
Transition to a ferromagnetic long-range ordered state was found at 0.60 Kin the orthorhombic Pphase crystal ofg-nitrophenyl nitronyl nitroxide (or 2-(4'-nitrophenyl)-4,4,5,5-tetramethyl-4,5dihydro-lH-imidazol-l-oxyl-3-N-oxide in the IUPAC nomenclature). This finding follows our recent discovery of the first organic bulk ferromagnet in the triclinic r-phase crystal of the same compound.
📜 SIMILAR VOLUMES
Molecular orbital calculations have been carried out for clusters of para-nitrophenyl nitronyl nitroxide (pNPNN) extracted from the experimental crystal structure of its p-phase. Three-dimensional effective exchange integrals (&,) are found to be positive (ferromagnetic). The ferromagnetic transitio
X-ray crystal analysis and magnetic measurements reveal the ferromagnetic linear chain with JF/kB=0.27 K in an a-nitronyl nitroxide, 2-(4-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1 -oxyl 3-N-oxide.
Semi-empirical and ab initio molecular orbital (MO) calculations have been carried out for clusters ofpnitrophenyl nitronyl nitroxide (p-NPNN) extracted from the experimental crystal structure of its y-phase. It is found that the intraplane exchange interactions (Jab) are ferromagnetic, whereas the
An a-nitronyl nitroxide cation radical, 2-( 3-N-methylpyridinium)-4,4,5,5-tetramethyl-4,5-dihydro-lH-imidazol-l-oxyl 3-Noxide, has been found to possess a unique structure and magnetic properties: the molecules are manifested as dimers with a very short intermolecular contact between the NO group an