The 6,6-closed and 5,6-open isomers of C60 and adamantylidene are synthesized by refluxing adamantylidene-diazirine and C60 in toluene. The yields of the monoadducts are optimized by successive addition of the diazirine while the reaction is followed by high performance liquid chromatography. Prior to isolation of the monoadducts, most of the the urneacted C60 is removed as precipitates by complexing with para-tert-butylcalix(8)arene. Separation is done on the Cosmosil Buckyprep column which provides the best resolution of the monoadducts among other columns tried including tetraphenylporphyrin (TPP), Regis Buckyclutcher I and Hypersil octyldecyl (ODS) columns. The structures of the adducts have been confirmed by carbon nuclear magnetic resonance spectroscopy. The 5,6-open isomer is fou...[ Read more ]

The 6,6-closed and 5,6-open isomers of C60 and adamantylidene are synthesized by refluxing adamantylidene-diazirine and C60 in toluene. The yields of the monoadducts are optimized by successive addition of the diazirine while the reaction is followed by high performance liquid chromatography. Prior to isolation of the monoadducts, most of the the urneacted C60 is removed as precipitates by complexing with para-tert-butylcalix(8)arene. Separation is done on the Cosmosil Buckyprep column which provides the best resolution of the monoadducts among other columns tried including tetraphenylporphyrin (TPP), Regis Buckyclutcher I and Hypersil octyldecyl (ODS) columns. The structures of the adducts have been confirmed by carbon nuclear magnetic resonance spectroscopy. The 5,6-open isomer is found to be the kinetic product. Its conversion to the thermodynamic product - the 6,6-closed adduct is possible by heat.

By reacting calix(8)arene with bromohexane or bromooctane, two new calixarene derivatives are obtained. With cavities capable of accommodating guests of appropriate sizes, their potential use as mobile phase modifiers in nonaqueous capillary electrophoresis have been evaluated. Regrettably, they show no improvement in the separation of fullerenes and aromatic acids. They are thought to be non-selective towards the analytes. Probably, the cavities have been rendered fluxional as the tert-butyl groups are not present and the intramolecular hydrogen bonding of the hydroxyl groups are disrupted such that the analytes cannot interact with the cavities selectively.