One-Pot Synthesis of a Novel Water-Soluble Fullerene-Core Starlike Macromolecule via Successive Michael and Nucleophilic Addition Reaction

Successive Michael and nucleophilic addition reaction of an (alpha),(beta)-unsaturated ester (n-butyl acrylate) with fullerenol in one pot leading to the formation of a novel water-soluble hydroxy ether terminated fullerene-core starlike macromolecule was classically demonstrated for the first time in fullerene chemistry. FTIR, UV-vis, and TGA techniques were employed for characterization. The chemical attachment of acrylate units to the fullerene core was clearly indicated from the disappearance of typical FTIR peaks of fullerenol (at 1593.2, 1381.2, and 1068 cm^-1) in the product. 1,2-Michael addition followed by nucleophilic addition reaction to the carbonyl group in acid-catalyzed reaction was monitored by the disappearance of typical alkene and carbonyl FTIR peaks of the parent acrylate and the appearance of alkane C-H stretching peaks (2964 cm^-1) and hydroxy peak (3426 cm^-1) in the product. The appearance of two absorption bands in the UV region, coupled with IR and TGA data, strongly indicate the formation of 1,4-Michael addition product in the case of base-catalyzed reaction. The attachment of about 3-4 acrylate units per fullerene core was determined by both gravimetric and thermogravimetric methods. Optical properties and thermal behavior of the products were shown to be influenced by the presence of fullerene.