Preparation of C₇₀H₂, C₇₀H₄, and C₇₀H₈:  Three Independent Reduction Manifolds in the Zn(Cu) Reduction of C₇₀

Abstract

This article reports the preparation of C70Hn species by Zn(Cu) reduction. The major products were one isomer of C70H2, one major isomer of C70H4, and one major isomer of C70H8. Several minor products were detected by UV−Vis and/or mass spectrometry. The structures of the major products were assigned as 1,2-C70H2, 1,2,56,57-C70H4, and 7,19,23,27,33,37,44,53-C70H8. Interestingly, although the major isomer of C70H4 is generated by reduction of the major isomer of C70H2, the major isomer of C70H8 is not generated by reduction of the major isomer of C70H2 or C70H4. The evidence suggests that there are at least three different reduction manifolds operating. One manifold includes 1,2-C70H2 and 1,2,56,57-C70H4, major products in which highly pyramidalized bonds near the poles of C70 are reduced. A second manifold includes 5,6-C70H2, a minor product. The third manifold consists of a set of C70H2, C70H4, and C70H6 species that are highly reactive and do not accumulate in solution. This third manifold leads to 7,19,23,27,33,37,44,53-C70H8. This third manifold is unique in that these compounds place hydrogens on nonadjacent carbons, a previously unobserved arrangement