New Examples of Donor-Acceptor Conjugated Systems Involving the 1,3-Dithiole Moiety

The crystal structures of 6-(4,5-dimethyl-2H-1,3-dithiol-2-ylidene)-6,7-dihydro-5H-dibenzo[a,c]cycloheptene-5,7-dione, C₂₀H₁₄O₂S₂, and 6-(4,5,6,7-tetrahydro-2H-1,3-benzodithiol-2-ylidene)-6,7-dihydro-5H- dibenzo[a,c]cycloheptene-5,7-dione, C₂₂H₁₆O₂S₂, have been determined. Strong intramolecular interactions are observed between the carbonyl groups of the seven-membered ring and the S atoms of the 1,3-dithiole ring.

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