Inorganic Chemistry, Vol.51, No.24, 13096-13102, 2012
Selective Synthesis, Isolation, and Crystallographic Characterization of LaSc2N@I-h-C-80
The successful preparation and isolation of the mixed-metal endohedral fullerene, LaSc2N@I-h-C-80, and its structural characterization by single-crystal X-ray diffraction are reported. Results from chemically adjusting plasma temperature, energy, and reactivity (CAPTEAR) experiments indicate that a 10 wt % addition of Cu(NO3)(2)center dot 2.5H(2)O to a mixture of La2O3 and Sc2O3 decreases the amount of C-60 and C-70 found in soot extracts by an order of magnitude. By combining a stoichiometric 2-fold excess of La to Sc atoms in the plasma reactor, an extract containing a greater abundance of LaSc2N@I-h-C-80 relative to Sc3N@I-h-C-80 was obtained. Alternatively, the stir and filter approach (SAFA method) can be used to remove the empty cage fullerenes from a carbon soot sample prepared without using Cu(NO3)(2)center dot 2.5H(2)O. LaSc2N@I-h-C-80 has been characterized by UV/vis absorption spectroscopy and by single-crystal X-ray diffraction. Ordered crystals with nearly identical orientations of the endohedral relative to the porphyrin have been obtained by cocrystallization of LaSc2N@I-h-C-80 with either Ni-II(OEP) or H-2(OEP). The LaSc2N unit is planar, although earlier computations suggested that it would be pyramidal.