Theoretical and experimental investigations of fullerene derivatives: C60H2, C60H4, C 70H2 and C60(CH2)2

摘要

Hydroboration of C(sub 70) in toluene yields a 2:1 mixture of 1,9-C(sub 70)H(sub 2) and 7,8-C(sub 70)H(sub 2). Equilibration of these two isomers in the presence of a Pt catalyst reveals a free energy difference of 1.4 (plus minus) 0.2 kcal/mol. Whereas semiempirical calculations have been found to predict the energy ordering of many fullerene derivatives incorrectly, ab initio Hartree-Fock (HF) calculations have been found to yield quantitative predictions of experiment. The HF/6-31G* level energy separation of 1,9-C(sub 70)H(sub 2) and 7,8-C(sub 70)H(sub 2) of 1.3 kcal/mol is in excellent agreement with experiment. Relative stabilities of isomers of bis(methano)fullerenes were found to parallel those of analogous C(sub 60)H(sub 4) isomers. Density functional theory (DFT) methods have been tested and are equivalent in accuracy to HF methods if similar basis sets are used. C(sub 60)H(sub 2) and C(sub 60)H(sub 4) can be efficiently produced on larger ((equal or >) 50 mg) scales with diimide generated from potassium azodicarboxylate and acetic acid in o-dichlorobenzene.