A Cerium Organic Framework with {Cu(2)I(2)} Cluster and {Cu(2)I(2)}(n) Chain Modules: Structure and Fluorescence Sensing Properties

In this work, a copper iodine module bearing a coordination polymer (CP) with a formula of [(Cu(2)I(2))(2)Ce(2)(INA)(6)(DMF)(3)]·DMF (1, HINA = isonicotinic acid, DMF = N,N’-dimethyl formamide) is presented. The title compound features a three dimensional (3D) structure, in which the {Cu(2)I(2)} cluster and {Cu(2)I(2)}(n) chain modules are coordinated by N atoms from a pyridine ring in INA(−) ligands, while the Ce(3+) ions are bridged by the carboxylic groups of INA(−) ligands. More importantly, compound 1 exhibits an uncommon red fluorescence (FL) with a single emission band maximized at 650 nm belonging to near infrared (NIR) luminescence. The temperature dependent FL measurement was applied to investigate the FL mechanism. Remarkably, 1 could be used as a FL sensor to cysteine and the nitro-bearing explosive molecule of trinitropheno (TNP) with high sensitivity, demonstrating its potential FL sensing applications for biothiol and explosive molecules.