Squaramide-coated Fe3O4 nanoparticles and their selective complexation with carboxylate anions in water

New hybrid squarate-nanoparticles for selective coordination of mono and dicarboxylates but not tricarboxylates, in water, are described. These hybrid squarate magnetic nanoparticles are obtained from the reaction between dopamine-ammonium squarate and Fe3O4. Also, it is shown how the iron magnetic nanoparticles are useful platforms to build receptors capable of displaying an effective molecular recognition and to show different behavior when the same binding unit is used with another spacer.