4-nitrophenyl nitronyl nitroxide

Zheludev, A., Bonnet, M., Ressouche, E. et al. (1994) Experimental spin density in the first purely organic ferromagnet the beta para-nitrophenyl nitronyl nitroxide, J. Mag. Mag. Mat, 135, 147-160. 

Figure 5.7. Optical microscope image of a thin film (thickness 2 p.m) of a-p-NPNN grown on a glass substrate (1.6 x 1.0 mm, crossed polarizers). Reprinted from Journal of Crystal Growth, Vol. 209, J. Caro, J. Fraxedas and A. Figueras, Thickness-dependent spherulitic growth observed in thin films of the molecular organic radical p-nitrophenyl nitronyl nitroxide, 146-158, Copyright (2000), with permission from Elsevier.

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.

In the above examples, a transition-metal atom is invariably present. As such, one might believe that the unpaired d electrons of the transition metal are the main cause of ferro/ferrimagnetic ordering, the organic/molecular species only playing a secondary role. There are a few examples of molecular magnets without the transition-metal atoms, albeit showing low T s. These are p-nitrophenyl nitronyl nitroxide (T = 0.6 K)... 

M. Kinoshita and P. Day, p-Nitrophenyl nitronyl nitroxide, the first organic ferromagnet, Philos. Trans. Roy. Soc. London 357 2855-2872 (1990). 

TMAFM) has recently been employed to characterize the surface morphologies of the polymorphs of an organic radical, / -nitrophenyl nitronyl nitroxide (Fraxedas et al. 1999a,b). 

Nakazawa, Y, Tamura, M., Shirakawa, N., Shiomi, D., Yakahishi, M., Kinoshita, M. and Ishikawa, M. (1992). Low-temperature magnetic properties of the ferromagnetic organic radical, / -nitrophenyl nitronyl nitroxide. Phys. Rev. B, 46, 8906-14. [200]... 

Turek, P, Nozawa, K., Shiomi, D., Awaga, K., Inabe, T., Maruyama, M. and Kinoshita, M. (1991). Ferromagnetic coupling in a new phase of the p-nitrophenyl nitronyl nitroxide radical. Chem. Phys. Lett., 180, 327-31. [200]... 

Among the few determinations of of molecular crystals, the CPHF/ INDO smdy of Yamada et al. [25] is unique because, on the one hand, it concerns an open-shell molecule, the p-nitrophenyl-nitronyl-nitroxide radical (p-NPNN) and, on the other hand, it combines in a hybrid way the oriented gas model and the supermolecule approach. Another smdy is due to Luo et al. [26], who calculated the third-order nonlinear susceptibility of amorphous thinmultilayered films of fullerenes by combining the self-consistent reaction field (SCRF) theory with cavity field factors. The amorphous namre of the system justifies the choice of the SCRF method, the removal of the sums in Eq. (3), and the use of the average second hyperpolarizability. They emphasized the differences between the Lorentz Lorenz local field factors and the more general Onsager Bbttcher ones. For Ceo the results differ by 25% but are in similar... 

Hydro nitronyl nitroxide 4.1 /7-Nitrophenyl nitronyl nitroxide. . 793... 

There are four polymorphic forms, a-, )5-, y-, and phase, known for p-nitrophenyl nitronyl nitroxide p-NPNN) [22—25] (Table 15.3). Each of them can be separately prepared by properly adjusting the conditions for depositing crystals [26]. The crystallographic constants of these phases are given in Table 15.3. The orthorhombic jS-phase is the most stable form and the other forms are subject to gradual phase change to the... 

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