Two Cd(II)-based metal-organic frameworks as difunctional fluorescence sensors to detect enrofloxacin and Fe3+

Two ternary Cd(II) metal-organic frameworks [Cd4(L)2(2,6-NDA)4·5H2O]n (1) and [Cd(L)0.5(1,8-NDA)·0.75H2O]n (2) (L ​= ​1,4-bis(1-(piperidin-4-ylmethyl)-1H-benzo[d]imidazole-2-yl)butane, 2,6-H2NDA ​= ​2,6-naphthalenedicarboxylic acid, 1,8-H2NDA ​= ​1,8-naphthalenedicarboxylic acid) were synthesized based on the L and two isomeric naphthalene dicarboxylic acids. 1 and 2 exhibit a 3D 4,4T11 and a 2D 3,4L13 network, respectively. Both 1 and 2 show remarkable thermal stability and can be used as difunctional fluorescence sensors for Fe3+ and enrofloxacin via a fluorescence quenching process with high sensitivity and selectivity. In addition, the fluorescence sensing mechanism was discussed in detail.