Selective colorimetric sensing of geometrical isomers of dicarboxylates in water by using functionalized gold nanoparticles.

A colorimetric sensing system based on gold nanoparticles functionalized with a water-soluble anion-recognition motif, an o-(carboxamido)trifluoroacetophenone analogue, has been developed. The nanoparticle system selectively senses specific isomers of dicarboxylates that are geometrically favorable for the binding-induced aggregation process; thus, it discriminates a trans-dicarboxylate fumarate from its cis-isomer maleate, and benzene-1,4-dicarboxylate from its isomeric benzene-1,2-and benzene-1,3-dicarboxylates in water, exhibiting a color change from red to blue.