Sc3N@(C-80-I-h(7))(CF3)(14) and Sc3N@(C-80-I-h(7))(CF3)(16). Endohedral Metallofullerene Derivatives with Exohedral Addends on Four and Eight Triple-Hexagon Junctions. Does the Sc3N Cluster Control the Addition Pattern or Vice Versa?

Mary A. Mackey, University of Southern Mississippi
Curtis E. Coumbe, University of Southern Mississippi
J. Paige Phillips Buchanan, University of Southern Mississippi
Steven Stevenson, University of Southern Mississippi

Abstract

The compounds Sc3N@(C-80-I-h(7))(CF3)(14) and Sc3N@(C-80-I-h(7))(CF3)(16) (2) were prepared by heating Sc3N@C-80-I-h(7) and Ag(CF3CO2) to 350 degrees C in a sealed tube. The structures of 1 and 2 were determined by single-crystal X-ray diffraction. They are the first X-ray structures of any endohedral metallofullerene with more than four cage C(sp(3)) atoms. The structures exhibit several unprecedented features for metallic nitride fullerenes, including multiple cage sp(3) triple-hexagon junctions (four on 1 and eight on 2), no cage disorder and little (2) or no (1) endohedral atom disorder, high-precision (C-C esd's are 0.005 angstrom for 1 and 0.002 angstrom for 2), an isolated aromatic C(sp(2))(6) hexagon on 2, and two negatively charged isolated aromatic C(Sp(2))(5)(-) pentagons on 2 that are bonded to one of the Sc atoms. DFT calculations are in excellent agreement with the two Sc3N conformations observed for 2 (Delta E(calc) = 0.36 kJ mol(-1); Delta E(exp) = 0.26(2) kJ mol(-1)).