Stabilizing cyclacene molecules

It is shown that introducing a single methylene group into each trannulene ring of a cyclacene molecule compels the formation of a non-bonded molecular orbital, NBMO, in the ring. The union of both trannulenes conforms to a first order perturbation change in the total energy according to Dewar'...

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Bibliographic Details
Published in:Turkish journal of chemistry 2010-01, Vol.34 (2), p.269-275
Main Author: SHANSHAL, MUTHANA
Format: Article
Language:English
Online Access:Get full text
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Summary:It is shown that introducing a single methylene group into each trannulene ring of a cyclacene molecule compels the formation of a non-bonded molecular orbital, NBMO, in the ring. The union of both trannulenes conforms to a first order perturbation change in the total energy according to Dewar's PMO theory. The NBMO coefficients can be calculated then according to Coulson's pairing theorem. The PMO calculated new HOMO-LUMO energies of the cyclacene indicate the relative stabilization of the singlet over the triplet state of the cyclacene. The results are confirmed by the DFT calculation of differently substituted bis, methylene cyclacenes. The same arguments apply to the introduction of 2 (donor + acceptor) substituents, e.g. NH2 + BH2 groups. Stabilizing the singlet state should facilitate the synthesis of the cyclacene.
ISSN:1303-6130
1300-0527
1303-6130
DOI:10.3906/kim-0811-10