SYNTHESIS OF OPEN-CAGE FULLERENE DERIVATIVES AND ENCAPSULATION OF SMALL MOLECULES

摘要

The thermal reaction of C_(60) with 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine proceeds via [4+2] cycloaddition followed by nitrogen extrusion to give an open-cage fullerene derivative with an eight-membered-ring orifice 4 in good yield. The orifice of 4 can be further enlarged into a 12-membered-ring by photochemical air-oxidation. This derivative can be transformed into derivative 1 having a 13-inembered-ring orifice containing sulfur by a thermal reaction with elemental sulfur in the presence of tetrakis(dimethylamino)ethylene. By applying high-pressure H_2 to this novel open-cage fullerene 1, 100% incorporation of a H_2 molecule into the fullerene cage has been achieved for the first time. Upon MALDI TOF mass spectroscopy, the removal of organic addends from the fullerene derivative 1 encapsulating H_2 and restoration of the pristine C_(60) cage, which retains approximately one third of incorporated H_2, have been observed.