Nitrile Oxides, Nitrones, and Nitronates in Organic Synthesis : Novel ...

108 NITRILE OXIDES
and acceptor substituents have been shown to have an inßuence on the redox
behavior of the fullerene adducts in cyclic voltammetry experiments (544). Thus,
3-R-substituted fullereno[1,2-d]isoxazolines 465 (R = 2,4,6-trimethoxyphenyl,
2,4,6-trimethoxystyryl, 2-(2-thienyl)phenyl) shows shifts of about 30mV or 40mV
to more negative values as compared with the reference compound (R = H).
Strong acceptor properties have been detected in the compounds with
R = CH=C(CO2Me)2, which show a positive shift of 30mV relative to R = H.
465
The data demonstrate that the electron-transfer rate in donor-substituted fullerenes
can be controlled by the electron-releasing property of the substituent as well
as by the electronic structure and/or length of the spacer used.
The synthesis of C60-based dyads in which the C60 core is covalently attached
to a strong electron acceptor moiety, has been carried out by 1,3-dipolar cycloaddition
of in situ generated nitrile oxides with C60. As expected, the obtained
adducts show reduction waves of the fullerene core that are anodically shifted in
comparison with the parent C60. This indicates that they are remarkably stronger
acceptors than C60.The electron acceptor organic addend also undergoes an anodic
shift due to the electronic interaction with the C60 moiety (545).
Properties of FeC60 solid samples have been studied by X-ray diffraction,
57 Fe Mossbauer spectroscopy and magnetic measurements to stimulate the interaction
of Fe with fullerene. FeC60 samples have been prepared by decomposition
of the 1,3-dipolar cycloadduct of the fullerene and ferrocene nitrile oxide. The
components exhibit super paramagnetic properties originating from an interaction
between FeC60 complexes within the nano-particles. Each nano-particle consists
of hundreds to thousands complexes (546).
REFERENCES
1. Grundmann C, Grünanger P. The Nitrile Oxides, Springer-Verlag, Berlin, 1971.
2. Huisgen R. In: 1,3-Dipolar Cycloaddition Chemistry, Padwa A (Ed.), Wiley-
Interscience, New York, Vol. 1, ch. 1, 1, 1984.
3. Caramella P, Grünanger P. In: 1,3-Dipolar Cycloaddition Chemistry, Padwa A (Ed.),
Wiley-Interscience, New York, Vol. 1, ch. 3, 291, 1984.
4. Torssell KBG. Nitrile Oxides, Nitrones, and Nitronates in Organic Synthesis. Novel
Strategies in Synthesis, VCH, Weinheim, ch. 1, 1; ch. 2, 55; ch. 5, 129, 1988.
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