Metal complexation induced supramolecular gels for the detection of cyanide in water
Dipankar Ghosh, DEEPA DEEPA, Krishna K. Damodaran
Abstract
The role of metal salts in inducing supramolecular gel network formation was analysed by reacting two pyridyl-N-oxide amides with various diamagnetic zinc(II) and cadmium(II) salts. Metal induced supramolecular gelation was observed for zinc(II) and cadmium(II) chloride complexes in water and the morphologies of the xerogels were analysed by scanning electron microscopy (SEM). The relative gel strength was corroborated with various non-bonding interactions observed in the solid-state structures of zinc(II) complexes using X-ray diffraction. The non-bonding interactions of the pyridyl-N-oxide amides and the metal complexes were compared to find the key interactions responsible for metallogel formation. The anion induced stimuli-responsive property of the metallogels was studied in the presence of halides and cyanide anions. The cadmium(II) gels were stable in presence of two equivalents of halides but the network collapsed in presence of cyanide anion in water and this property can be used to detect cyanide anions in water.