Highly regioselective derivatization of trimetallic nitride templated endohedral metallofullerenes via a facile photochemical reaction.

Photochemically generated benzyl radicals react with Sc(3)N@C(80)-I(h) to produce a dibenzyl adduct [Sc(3)N@C(80)(CH(2)C(6)H(5))(2)] in 82% yield and high regioselectivity. The adduct's (1)H spectrum revealed high symmetry: only one AB pattern was observed for the methylene protons. The (13)C NMR spectrum suggested a C(2)-symmetrical structure. DFT calculations reveal that a 1,4-adduct is more favorable than a 1,2-adduct by >10 kcal/mol. The 1,4-structure on [566] ring junctions was unambiguously confirmed by X-ray crystallographic analysis. UV-vis spectra revealed that the removal of two p orbitals from the pi system of the cage together with the benzylic substituents change the electronic properties of the metallofullerene in a manner similar to those reported for disilirane and trifluoromethyl moieties. Under the same conditions from Lu(3)N@C(80)-I(h) we prepared (63% yield) Lu(3)N@C(80)(CH(2)C(6)H(5))(2), which demonstrated properties similar to the 1,4-dibenzyl adduct of Sc(3)N@C(80)-I(h).