Selective Detection of Phosphate Ion in Aqueous Medium by a Cobalt(II) Based Coordination Polymer

In the present study, we have designed a new water soluble cobalt(II) based one-dimensional (1D) coordination polymer (CP1) for the detection of trace quantities of phosphate ions in aqueous medium. The synthesized coordination polymer was characterized by various spectroscopic, including UV-vis, FTIR, EPR, X-ray diffraction (s-XRD & p-XRD) and analytical techniques to ascertain its structural composition. We have carried out the DFT studies which revealed that HOMO electron density is concentrated over ion central metal and the nitrate ion whereas the electron density of the LUMO is primarily localized over the ligand moiety and partially distributed on the metal ion. Moreover, Hirshfeld surface analysis were aslo performed to substantiate the stability of crystal lattice through intermolecular interactions. We have further examined the sensing activity of the CP1 polymer for the detection of various hazardous inorganic pollutants. Interestingly, a distinctive response by CP1 was noticed in presence of phosphate ions as was substantiated from observing remarkable changes in the electronic and luminescent spectra of the polymer, thereby allowing the quantitative/qualitative detection of phosphate ions even at very lower concentrations.