Methylation of [76]fullerene and [84]fullerenes; the first oxahomo derivatives of a higher fullerene.
Methylation of [76]fullerene by reaction with Al-Ni alloy/NaOH followed by quenching of the intermediate anions with methyl iodide gives a mixture of methylated and methylenated products together with oxide derivatives. The major derivatives are five isomers of C(76)Me(2)(one of C(s) symmetry due to 1,6-C(76)Me(2)) and C(76)(CH(2))(n)(n= 2-4), together with corresponding mono-oxides. The single line (1)H NMR spectrum of mono-oxide C(76)Me(2)O shows it is an oxahomofullerene (ether) the first example derived from [76]fullerene, oxygen being inserted between the CMe groups in 1,6-C(76)Me(2)giving a product of C(2) symmetry. The probable structures of the unsymmetrical dimethyl derivatives have been deduced from heats of formation calculated by AM1 and density functional methods. Bis-oxide C(76)Me(4)O(2) is the first bis oxahomo[76]fullerene to be isolated and gives two equal-intensity lines in the (1)H NMR spectrum showing that it must also have C(2) symmetry; probable structures are considered. Methylation of [84]fullerene takes place less readily and only four C(84)Me(2) derivatives were isolated, two of them in quantities sufficient to show the symmetries as C(1), and either C(2) or C(s).
Darwish
Adam D
AD
The Chemistry Laboratory, Sussex University, Brighton, UK BN1 9QJ.
Martsinovich
Natalia
N
Taylor
Roger
R