Buckybowl anions

R142 D. Eisenberg, R. Shenhar and M. Rabinovitz, Anions in Buckybowls , in Fragments of Fullerenes and Carbon Nanotubes Designed Synthesis, Unusual Reactions, and Coordination Chemistry, eds. M. A. Petrukhina and L. T. Scott, John Wiley Sons, Inc., Hoboken, N. J., 2012, p. 63. 

Anions of other buckybowls were also characterized by NMR spectroscopy. For example the dianions and tetranions of dibenzocorannulene 25 and dibenzocydo-pentacorannulene 60 were reported by Rabinowitz et al. [53], In these cases, however, the tetraanion stage of reduction could be achieved only with K metal. No sandwich type dimerization similar to tetralithio-1 was observed for these larger systems. 

A quite different approach to the complexation of corannulene derivatives with transition metals was applied by Chin [65]. His group hydrogenated 1 to its octahy-dro derivative 67 which was subsequently deprotonated by BuLi to the respective fluorene-type anion 68. This species was then used for the formation of two complexes with (CpZrCh) and [Re(CO)3]+. In both cases X-ray structure determination showed // coordination of the metal to the central ring on the exo (convex) side of the very shallow bowl of 68. However, these complexes relate more to the fluorene anion chemistry than to buckybowls. 

The preparation, stabilization, and characterization of buckybowl anions, ranging from archetypal corannulene to large hemifullerenes, have been reviewed. The synthetic potential and configurational stability of configurationally labile chiral carbanions next to electron-withdrawing groups has been summarized. ... 

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