Structure of the Hydration Product of the C60-Di(2-pyridyl)-1,2,4,5-tetrazine Adduct

A solid-state reaction of fullerene C60 with 3,6-di(2-pyridyl)-1,2,4,5-tetrazine using the high-speed vibration milling technique gives almost quantitatively the monoadduct 2, which is transformed in high yield upon contact with silica gel to a novel 1,2,3,4-tetrahydro-C60 derivative 3 having a 2-pyrazoline ring fused at unusual 2,3-positions of the C60 framework. This unexpected product is the result of the addition of a water molecule to an imine moiety of 2, followed by a series of rearrangements.