Modeling complexes of H2 molecules in fullerenes

Abstract Molecular mechanics calculations indicate that the closure, with the preservation of two H 2 guests inside C 70 host, of the recently synthesized fullerene complex having the cage with a hole, can prove very difficult. C 76 of D 2 symmetry seems to be the smallest fullerene for which the endohedral complex with two guest molecules can be obtained while that with three guests must be larger than C 80 . These results and the analysis of spatial relationships for the recently published semiempirical quantum calculations for 24H 2 @C 60 cast doubts in the reliability of low level quantum calculations for supramolecular systems.