Preparation of C₇₀H₂, C₇₀H₄, and C₇₀H₈: Three independent reduction manifolds in the Zn(Cu) reduction of C₇₀

This article reports the preparation of C₇₀H(n) 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.