Jump to main content
Jump to site search

Issue 23, 2013
Previous Article Next Article

(E)-5,5′-Di(thiophen-2-yl)-3,3′-bi[thiophen-3(2H)-ylidene]-2,2′-diones—from conspicuous blue impurities to “quasi-metallic” golden-bronze crystals

Author affiliations


(E)-5,5′-Di(thiophen-2-yl)-3,3′-bi[thiophen-3(2H)-ylidene]-2,2′-dione (1a) has caught the eye of several chemists who have encountered it as a trace by-product in a variety of reactions. We report here the first deliberate synthesis of this intense blue dye (λmax 635 nm; εmax 32 400 L cm−1 mol−1). We prove on the basis of predictions made with TDDFT that 1a has previously been misassigned as a structural isomer and we correct the visible absorption data that was reported. Derivatives of 1a equipped with pentyl (1b) and butylsulfanyl (1c) groups are readily prepared with our divergent synthetic route (3–7% yield over five steps). Crystals of 1b and 1c exhibit an attractive “quasi-metallic” golden-bronze lustre. This effect is rare in molecular crystals and is observed only with the most intense dyes.

Graphical abstract: (E)-5,5′-Di(thiophen-2-yl)-3,3′-bi[thiophen-3(2H)-ylidene]-2,2′-diones—from conspicuous blue impurities to “quasi-metallic” golden-bronze crystals

Back to tab navigation

Supplementary files

Publication details

The article was received on 20 Feb 2013, accepted on 30 Apr 2013 and first published on 08 May 2013

Article type: Paper
DOI: 10.1039/C3OB40373D
Citation: Org. Biomol. Chem., 2013,11, 3871-3879
  •   Request permissions

    (E)-5,5′-Di(thiophen-2-yl)-3,3′-bi[thiophen-3(2H)-ylidene]-2,2′-diones—from conspicuous blue impurities to “quasi-metallic” golden-bronze crystals

    N. R. Evans and A. J. P. White, Org. Biomol. Chem., 2013, 11, 3871
    DOI: 10.1039/C3OB40373D

Search articles by author