Novel [60]fullerene polymers: Part 2: Synthesis and polymerisation processes through acrylation of N-(4-hydroxyphenyl)-o-hydroxy-2-phenyl fulleropyrrolidine derivatives and their monomers

Abstract

Following on from part 1 of this paper where linear C60 polymers were synthesised, part 2 describes the synthesis of crosslinked and branched chain C60 polymers so that the amount of C60 content in the polymer, the number averaged molecular weight “Mn” and the weight averaged molecular weight “Mw” may be increased. This paper reviews the method in which fulleropyrrolidines were prepared by [3 + 2] cycloaddition of azomethine ylides to [60]fullerene cage through the use of N-(4-hydroxyphenyl) glycine in conjunction with benzaldehyde derivatives. Numerous types of [60]fullerene polymers were synthesised through fulleropyrrolidine acrylic monomers. In this study, the cycloaddition process was selected because it provides a powerful tool for fullerene functionalisation, as a result very stable cycloadducts are formed. The addition of azomethine ylide was found to provide a versatile method for the derivatization of [60]fullerene. In this case, the synthesis of functionalised C60 and novel branched chain and crosslinked network of fullerene polymers has been investigated. The first step in this study was to prepare dihydroxy fulleropyrrolidines by [3 + 2] cycloaddition of azomethine ylide to [60]fullerene. The fulleropyrrolidine monomer having multiple functional groups was put up by the reaction of –OH groups of fulleropyrrolidine with acryloyl chloride in the presence of a base in an alcoholic solution. FT-IR, Mass spectra,1H NMR and UV techniques were used to characterise the reaction products obtained. Benzoyl Peroxide was used as a free radical initiator to polymerise the monomer in dimethylformamide. DMF is a highly suitable solvent for this procedure because both C60 monomer and polymer are soluble. In this work, the process parameters such as time of reaction, reaction temperature, mole ratio, type of solvent, and quantity of reagents used were varied in so as to obtain the highest yields of fulleropyrrolidines, monomers and polymers.