Homoconjugation vs. exciton coupling in chiral α,β-unsaturated bicyclo[3.3.1]nonane dinitrile and carboxylic acids.
Molecules 2014;
19:9893-906. [PMID:
25006793 PMCID:
PMC6270784 DOI:
10.3390/molecules19079893]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Revised: 06/03/2014] [Accepted: 06/05/2014] [Indexed: 11/17/2022] Open
Abstract
The chiroptical properties of enantiomerically pure bicyclo[3.3.1]nona-2,6-diene-2,6-dicarbonitrile and related acids were studied by circular dichroism spectroscopy and theoretical computations. A consideration of the molecular structure of the synthesized difunctional compounds revealed that chromophores are predisposed to transannular through-space interaction due to a favourable conformation of the bicyclic skeleton and a rather small interchromophoric distance. Evidence for non-exciton-type coupling between the two acrylonitrile and acrylate moieties in 3 and 4, respectively, was obtained by chiroptical spectroscopy and DFT calculations.
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