Colorimetric anion chemosensors based on anthraquinone: naked-eye detection of isomeric dicarboxylate and tricarboxylate anions

Three new colorimetric anion receptors 1-3 were synthesized and characterized. Among them, both 1 and 3 showed good sensitivity and selectivity for discrimination of maleate vs. fumarate or malate vs. tartrate by dramatic colour changes in DMSO or DMSO-H2O (95 : 5). Thus, both 1 and 3 can be used as optical chemosensors for recognition of maleate vs. fumarate or malate vs. tartrate anion. Besides that, the receptor 1 has also a unique colour change for recognition of either cis-aconitate or trans-aconitate in DMSO, accordingly it can be used for detection of each isomer and discrimination of cis-aconitate from trans-aconitate anion.