Metal-containing trifurcate receptor that recognizes and senses citrate in water.

The binding tendencies toward carboxylates of a trifurcated receptor containing three copper(II)−cyclam subunits have been investigated in pure water, through the displacement of a fluorescent indicator. The receptor is tailor-made for the recognition of tricarboxylates, e.g., citrate, whose three negatively charged oxygen atoms interact with the three coordinatively unsaturated CuII centers.