Unveiling Role of Metals in Mononuclear Metal-Complexes for Chemodosimetric Detection of S~(2-)from aqueous medium:Experimental and DFT Corroboration with Real-Field Application

摘要

Herein,we have reported two isostructural mononuclear metal complexes [M(HL)2(ClO4)2],wherein,M= Co2+(viz.SN-1)and Ni2+(viz.SN-2)and HL is NNO donor Schiff-base ligand i.e.((E)-2-methyl-2-((pyridin-2-ylmethylene)amino)propan-1-ol)for unveiling as molecular sensor for S~(2-)(sulphide)like hazardous entity.The molecular probes have been characterized by SCXRD,1H-NMR,FT-IR,HRMS etc.X-ray diffraction studies confirm the mono-nuclear structures of both the complexes.Interestingly,SN-1 exhibited remarkable sensitivity towards S~(2-)by naked eye colour change in purely aqueous medium with detection limit of 33.5 nM and binding constant of 11.05 × 10~8 M~(-1)while the SN-2 didn't show any subtle chromogenic changes upon interaction with the targeted analyte.Judicious choice of metal centre plays a pivotal role for such discriminative interacting behaviour.Spectroscopic and DFT studies shed light on the mechanistic pathway of host-guest interaction,indicating a S~(2-)mediated chemodosimetric approach following HSAB principle.Impressively,the SN-1 has also been explored towards fabrication of test strips for on-field detection of H2S/S~(2-)via."Dip-Stick"approaches.In a nutshell,the presently developed simple mono-nuclear metal complex can be utilised for detecting gasotransmitter like H2S/S~(2-)from purely aqueous medium that may be helpful in fabricating"point-of-care"devices in coming days for better understanding of H2S as a key role maker in various health related issues.