ABSTRACT

In this work I present an investigation of a number of novel materials based on the fullerenes. My research started with the successful synthesis and separation of fullerene C60. I synthesized the magnetic material TDAE-C60 and studied its optical and magnetical properties. I discovered that orientational ordering of C60 molecules, at around 170 K is directly coupled to spin ordering at 16 K and is crucial for understanding of magnetism in this material. Doping C60 with other electron donors I found no improves at the magnetic properties in this materials compared to TDAE-C60. Therefore the properties of C60 molecule were changed with the synthesis of its derivatives. I performed the cyclo addition of diazo compounds, radical and Fridel Crafts reactions and also brominations on C60. In described ways I synthesized a series of mono and poly adducts of C60. I synthesized and characterized charge transfer complexes of C60 derivatives with TDAE and cobaltocene and found different types of magnetic behavior in those materials. The temperature dependence of ESR showed a Curie-Weiss type of behavior for some materials. In the other materials, however, magnetic transitions were observed with a ferro- or antiferro-magnetic spin coupling below the temperature of the magnetic transition. Two materials are showing a cusp, similar to TDAE-C60, in the low temperature static magnetic susceptibility. Complex Cp2Co-C61C12H6(NO2)2 shows magnetic transition with Tc = 8 K and Cp2Co-C61HPh(4)NO2 with Tc = 28 K, the latter being the highest of the organic materials reported so far. We measured also luminescence of the synthesized C60 derivatives and observed that the luminescence in the monoadducts is similar to C60. However, enhanced luminescence was observed in polyphenylated derivatives obtained with radical and Friedel Crafts reaction, which could be compared even to the luminescence of a laser dye. Results of absorption and luminescence measurement showed, that electronic properties of C60 monoadducts are quite similar to C60, whereas in case of polyadducts differences are more profound.