Anions corannulene tetraanions

There have been several developments in this area since this manuscript was prepared. The heat of combustion of corannulene was determined by microbomb combustion calorimetry and its gas-phase enthalpy of formation was estimated at 110.8 kcal/mol. All anionic oxidation states of corannulene were observed by optical absorption, EPR, and NMR spectroscopies. More support for the an-nulene-within-annulene model of the corannulene tetraanion was presented. An alternative pyrolysis route to corannulene was reported, as well as some attempts toward the synthesis of bowl-shaped subunits of fullerenes. And in contrast with previous semiempirical studies," ab initio calculations predicted a general concave preference for the metal cation binding to semibuckminsterfullerene 2%. ... 

The esthetically attractive an anion inside a trianion model was proposed for the tetraanion of corannulene based on the early models of electron distribution in corannulene [51], This view, however, has been a matter of some controversy, since while some of the spectral characteristics of the tetraanion seem to be explained well by this model, the charge- C NMR relations as well as the results of early ah initio calculations suggest that more than three extra electrons go to the rim of corannulene upon the tetraanion formation [52],... 

Following the dimerization of corannulene, a system of two tethered corannulene units, 1,8-dicorannulenyloctane (38) [118], was reduced with alkali metals to study the formation of an intramolecular sandwich [8]. The reduction was done with Li, Na, K, Rb and Cs, and the two diamagnetic anions tetraanion and octa-... 

Compounds 40 and 41 do not contain the dibenzofulvene subunit, which is responsible for the dimerization process in 39 therefore, their reduction produces only monomeric anions. The LUMO level in 40 and 41 is not doubly degenerate like that of corannulene, but there is rather a small energy gap between the LUMO and the NLUMO, which indicates that the formation of tetraanions of 40 and 41 should be possible [120]. 

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