Highly efficient coordination of Hg super(2+) and Pb super(2+) metals in water with squaramide-coated Fe sub(3)O sub(4) nanoparticles

The synthesis and binding properties of squaramide-coated Fe sub(3)O sub(4) nanoparticles upon coordination with heavy metals in water are described. The nanoparticles feature selective binding towards Hg super(2+) and Pb super(2+) cations in the presence of other interfering heavy metals. The binding affinity of the nanoparticles is especially high for mercury and lead cations. The mode of action of the squaramide-coated nanoparticles differs significantly from that of previously reported nanoparticles used as Hg super(2+) scavengers. The selective Hg super(2+) sequestering capabilities displayed by the squaramide-coated nanoparticles are related to the formation of organomercury compounds. The solid state structure of the organomercury complex obtained by treatment of a di-squaramide with Hg super(2+) salts is described, demonstrating the mercuriation of the aryl moiety of dopamine.