Synthesis of calixarene-based ketocyanine fluorophores

Cup-shaped calix[4]arenes bearing one or two ketocyanine fluorophore fragments at the wide rim of the macrocycle are synthesized by condensation of formyl calix[4]arenes with arylmethylene(hetarylmethylene)cyclopentanones in the presence of the ionic liquid, dimethylammonium dimethylcarbamate (DIMCARB) and characterized using UV-vis and fluorescence spectroscopy. Strong positive solvatofluorochromism for the calixarene ketocyanines is observed.