Synthesis and Properties of Fullerene-Containing Catenanes and Rotaxanes and Their Application into Molecular Machines

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The present study aims at the preparations of the fullerene-containing catenanes and rotaxanes by using donor-acceptor interaction and the elucidation of their properties.I have prepared [60]fullerene monoadducts 1a-c possessing an electron-deficient naphthalenetetracarboxylic diimide moiety as common starting materials for the catenanes and rotaxanes, and succeeded in the preparation of rotaxanes 3 and catenanes 4 by combining 1a-c with electron-rich dinaphthocrown ether 2.The intramolecular Bingel reactions of monoadducts 1 in the presence of 2 at -78 ℃ successfully afforded novel neutral [2]catenanes 4 with D-A-D-A stacking structure, while the intermolecular Bingel reactions of 1 with excess [60]fullerene gave [2]rotaxanes 3. Both catenanes 4 and rotaxanes 3 were isolated by column chromatography (silica gel) and GPC, and characterized by ^1H NMR, MALDI-TOF mass, and UV-Vis spectroscopies. [2]Catenane 4 (n = 2), which includes a [60]fullerene bisadduct moiety, was successfully separated by HPLC into three regioisomers, which were identified as trans-2, trans-3, and e by UV-Vis spectroscopy. The lowering of reaction temperature is critical for the formation of [2]catenanes and [2]rotaxanes.The UV-Vis spectra of rotaxanes 3 show a new band assigned to the CT-band in the region of 400-500 nm. In the fluorescence spectra of rotaxanes 3, the emission of dinaphthocrown ether moiety was significantly quenched, mainly due to the energy and/or electron transfer to the naphthalenetetracarboxylic diimide and/or fullerene moiety.In order to increase the yield of the catenanes and rotaxanes, the use of [60]fullerene monoadducts carrying a more electron-deficient perylene diimide moiety is now examined.