Charge-localized and -delocalized Valence Tautomeric Forms of Cyclic Oxocarbon Dianions

3 Charge-localized and -delocalized Valence Tautomeric Forms of Cyclic Oxocarbon Dianions 

For over four decades, interest in the family of cyclic oxocarbon dianions has focused on their aromaticity and molecular structure. Theoretical studies have indicated that aromaticity decreases with increasing ring size, and CeOg possesses only a small degree of aromatic character [47, 51]. Furthermore, while it is firmly established that the 

In the host lattice of 24, the rhodizonate dianion resides at an inversion center, being directly linked to a pair of A -(3-hydroxyphenyl)urea molecules through pairs of N-H- -0 [A, N2 = R 9)] and phenyl C-H- -0 [B, N2 = f 2(6)] hydrogen bonds 

As previous theoretical [54] and experimental [55] studies on the system indi- 

Enediolate C2v valence tautomer of croconate. To create an asymmetric hydrogen-bond donor environment that stabilizes the C2v valence tautomer of CsOs , we 

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