New topological Zn metal organic frameworks as multi-responsive fluorescent sensing materials for detecting Fe3+, Cr2O72−, CrO42− and tetracycline in aqueous system

Abstract

Three new Zn metal organic frameworks (Zn-MOFs), {[Zn2(L)[H (1,4-bmib)]]·1.5(H2O)}n (1), {[Zn2(HL) (3,5-bip)2]·(H2O)}n (2), and {[Zn2(HL) (4,4′-bbibp)2]·4(H2O)}n (3), have been first synthesized based on a flexible H5L ligand with ether functional group (C–O–C) and successfully characterized (semi-flexible H5L ​= ​3,5-bis(3,5-dicarboxylphenoxy)benzoic acid, flexible 1,4-bmib ​= ​1,4-bis(2-methylimidazol-1-yl)butane, rigid 3,5-bip ​= ​3,5-bis(1-imidazolyl)pyridine, and rigid 4,4′-bbibp ​= ​4,4′-bis(benzoimidazo-1-ly)biphenyl). Zn-MOFs 1–3 are unique topological networks. As multi-responsive fluorescent sensing materials of 1 and 3, they show excellent response and sensitivity for Fe3+, CrO42− and Cr2O72−, and tetracycline (TC) in aqueous system. The quenching mechanism is also investigated in detail.