A novel monocapped square-antiprismatic Ba(II) coordination polymer: a design for dual-responsive fluorescent chemosensor for Cr2O72− and Fe(III)

One monocapped square-antiprismatic Ba(II) coordination polymer [Ba4(L)2(H2O)8·H2O]n (Ba-CP1, H4L ​= ​1,1’-(1,4-phenylenebis(methylene))bis(1H-pyrazole-3,5-dicarboxylic acid), was designed and synthesized via self-assembly processes. Structure of the complex was characterized by X-ray single crystal analysis, with features of Ba–O metal-inorganic chains linked to carboxylate oxygen atoms from a six-dentate flexible chelating ligand to construct a complicated 3D Ba-metal-organic framework. Optically, luminescent investigations show that this Ba-CP is an excellent CP-based fluorescent probe, with high sensitivity for environmentally relevant Fe3+ and Cr2O72− ions. This is the first Ba-CP dual-responsive fluorescent material recognizing Fe3+ or absorbing Cr2O72− ions in DMF solution.