Nano-Sized [60]Fullerene-Cyclodextrin Molecules
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Nano-Sized [60]Fullerene-Cyclodextrin Molecules Jeong-Seo Park, Han-Chang Kang, and Kurt E. Geckeler* Laboratory of Applied Macromolecular Chemistry, Department of Materials Science and Engineering, Kwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Kwangju 500-712, South Korea ABSTRACT As [60]fullerene is a very hydrophobic macromolecule, there have been a number of attempts to make it more hydrophilic for biomedical applications. By attaching hydrophilic moieties such as poly(oxyethylene)(POE) chains and cyclodextrin molecules to [60]fullerene, novel water-soluble and biocompatible materials have been successfully prepared [1,2]. The synthesis of novel macrocyclic fullerene conjugates which are water-soluble is reported. The telechelic fullerene derivatives have been prepared via addition reaction of POE-based arms with covalently bonded β-cyclodextrin (CD) to [60]fullerene. To this end, a mono-tosylated CD derivative has been prepared in pyridine and then reacted with an aminofunctional POE in the presence of triethylamine. The subsequent reaction of [60]fullerene with the hydrophilic POE-conjugated CD-derivative yielded the macrofullerene after separation and purification procedures. The macrocyclic [60]fullerene derivatives obtained were soluble in water and characterized by UV-VIS and FT-IR spectroscopy as well as light scattering measurements and thermogravimetric analysis.
INTRODUCTION Since [60]fullerene has been made preparatively accessible [3], the promising properties of [60]fullerene stimulate an increasing interest for fullerene-containing polymers in view of biomedical applications [1,2]. There have been a number of attempts to make it more hydrophilic, as [60]fullerene possesses radical scavenging effects [4]. POE exhibits the minimal interfacial energy in an aqueous environment and an unique solubility in water. Furthermore, as POE is a very hydrophilic and biocompatible material, it is already applied in many fields such as biomedical and pharmaceutical areas [5]. And CD are water-soluble cyclic oligosaccharides built up of glucopyranose units. Thus, by using of [60]fullerene as a molecular core in linking multiple POE chains and CD molecules novel water-soluble and biocompatible materials have been successfully prepared.
EXPERIMENTAL DETAILS The synthetic procedure consists of three steps. The first step is the preperation of mono6-(p-tolylsulfonyl)-β-cyclodextrin (m-TsCD). m-TsCD was synthesized by following a standard procedure [6]. The second step was the preparation of mono-poly(oxyethylene)-β-cyclodextrin (POECD). It was synthesized by reacting equimolar quantities of m-TsCD and difunctional amino POE (aPOE) with a molecular mass 2 kg mol-1. W7.3.1
In the final step, we synthesized the (aPOE)-poly(oxyethylene)-β-cyclodextrin (F-(POECD)n) by reacting with POE-CD and [60]fullerene. During the reaction, the color of solution changed from purple to light-yellow, and then to pink. UV/Vis spectra were obtained with a UV/Visible spectrometer (Perkin Elmer, Lambda 12). The parti
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