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

This article reports the preparation of C 70 H n species by Zn(Cu) reduction. The major products were one isomer of C 70 H 2, one major isomer of C 70 H 4, and one major isomer of C 70 H 8 . Several minor products were detected by UV−Vis and/or mass spectrometry. The structures of the major products were assigned as 1,2-C 70 H 2, 1,2,56,57-C 70 H 4, and 7,19,23,27,33,37,44,53-C 70 H 8 . Interestingly, although the major isomer of C 70 H 4 is generated by reduction of the major isomer of C 70 H 2, the major isomer of C 70 H 8 is not generated by reduction of the major isomer of C 70 H 2 or C 70 H 4 . The evidence suggests that there are at least three different reduction manifolds operating. One manifold includes 1,2-C 70 H 2 and 1,2,56,57-C 70 H 4, major products in which highly pyramidalized bonds near the poles of C 70 are reduced. A second manifold includes 5,6-C 70 H 2, a minor product. The third manifold consists of a set of C 70 H 2, C 70 H 4, and C 70 H 6 species that are highly reactive and do not accumulate in solution. This third manifold leads to 7,19,23,27,33,37,44,53-C 70 H 8 . This third manifold is unique in that these compounds place hydrogens on nonadjacent carbons, a previously unobserved arrangement.