Metal complexes of dual-pendant sulfonate bis(indolenine)squaraines

D. E. Lynch, Martin Cox

    Research output: Contribution to journalArticlepeer-review

    2 Citations (Scopus)


    Eight metal complexes of dual-pendant sulfonate bis(indolenine)squaraines (four d-transition metals and four f-transition metals) have been prepared and examined as fluorescent probes for solution protein determination. Of the eight, the cobalt-squaraine complex exhibited the highest fluorescence response in the presence of protein (in aqueous solution) and the partial determination of its crystal structure meant that it could be examined further and compared against the previously determined bis-piperidinium and bis-morpholinium squaraine species. Comparative examination of these three variants in water, 10 mM phosphate buffer (pH = 7.0), and 10 mM Tris/HCl buffer (pH = 7.0) led to the conclusion that the use of Tris/HCl buffer resulted in less reduction of fluorescence intensity (over that of water alone) than the more widely used phosphate buffer.
    Original languageEnglish
    Pages (from-to)192-198
    JournalDyes and Pigments
    Early online date19 Mar 2015
    Publication statusPublished - Jul 2015

    Bibliographical note

    The full text is not available on the repository.


    • Squaraine dyes
    • Metal-squaraine complex
    • X-ray crystal structure
    • Fluorescence
    • Protein detection
    • Fluorescence probes


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