A luminescent Cd() coordination polymer as a multi-responsive fluorescent sensor for Zn, Fe and CrO in water with fluorescence enhancement or quenching

A luminescent Cd( ii ) coordination polymer, namely {[Cd(btic)(phen)]·0.5H 2 O} n (CP- 1 ) (H 2 btic = 5-(2-benzothiazolyl)isophthalic acid, phen = 1,10-phenanthroline), was constructed through the mixed-ligand method under solvothermal conditions. CP- 1 manifests a chain structure decorated with uncoordinated Lewis basic N and S donors. CP- 1 exhibits high sensing towards Zn 2+ , Fe 3+ and Cr 2 O 7 2− ions with fluorescence enhancement or quenching. CP- 1 exhibited a fluorescence enhancement for Zn 2+ ions through weak binding to S and N atoms, and a fluorescence quenching for Fe 3+ and Cr 2 O 7 2− ions by an energy transfer process. The binding constants were calculated as 1.812 × 10 4 mol −1 for Zn 2+ , 4.959 × 10 4 mol −1 for Fe 3+ and 1.793 × 10 4 mol −1 for Cr 2 O 7 2− . This study shows CP- 1 as a rare multi-responsive sensor material for the efficient detection of Zn 2+ , Fe 3+ and Cr 2 O 7 2− ions. A luminescent Cd( ii ) coordination polymer can act as a multi-responsive sensor for efficiently detecting Zn 2+ , Fe 3+ and Cr 2 O 7 2− ions.