Ionic nature of cadmium polymer plays decisive role in selective dye adsorption

Abstract

A new coordination polymer {[Cd3(EGTA)(H2O)5]·(NO3)2}n1 was synthesized by using cadmium nitrate salt and flexible carboxylate EGTA (ethylene bis(oxyethylenenitrilo)tetraaceticacid) ligand under hydrothermal condition. The structure of 1 was characterized by FT-IR spectroscopy, elemental analysis and single crystal X-ray diffraction techniques. Complex 1 displayed 2D structure with uninodal 4-connected underlying net of a rare kgm topology with point symbol {32.62.72}. All three Cd(II) in the complex exhibited different geometrical configuration such as distorted square antiprism geometry, distorted trigonal pyramidal and distorted square pyramidal geometry. Additionally, TGA property of complex 1 was also studied. The anionic dyes (methyl orange and congo red) were studied to examine the potential of complex 1 for removal of dyes from aqueous solution. Interestingly, ionic nature of complex 1 played decisive role in removal of anionic dye within 15 min as two nitrate ion present in the lattice could influence the adsorption performance.