Heterometallic Hybrid Open Frameworks: Synthesis and Application for Selective Detection of Nitro Explosives

Abstract

Three inorganic–organic hybrid open frameworks based on heterometallic cluster building blocks, formulated as Cd2Cs3(NDC)3(OAc)(DMA)2(H2O) (1), [NH2(CH3)2]2·Cd2Mg(NDC)4·Gx (2), and [NH2(CH3)2]3·Cd2K(NDC)4·Gx (3) (H2NDC = 2,6-naphthalenedicarboxylic acid, G = guest solvent molecule), were synthesized under solvothermal conditions. Compound 1 has a pillared layered structure featuring inorganic hcb-type layers with 14-ring windows and simultaneously exhibits a 3D open framework constructed from two types of heterometallic clusters, i.e., {Cd2Cs2O18} and {CdCs4O18}, and the NDC2– ligand. Compounds 2 and 3 are constructed from linear trinuclear {Cd2M} (M = Mg and K) building blocks and the NDC2– ligand, featuring 1D square channels with rld-z topology. Of the three heterometallic hybrid open frameworks, compounds 1 and 2 exhibited strong blue-light emission due to the presence of fluorescent organic ligands in the anionic frameworks, and more importantly, their strong fluorescence could be selectively quenche...