A new luminescent anionic metal-organic framework based on heterometallic zinc(II)-barium(II) for selective detection of Fe 3+ and Cu 2+ ions in aqueous solution.

Over the past two decades, the development of novel inorganic-organic hybrid porous crystalline materials or metal-organic frameworks (MOFs) using crystal engineering has provoked significant interest due to their potential applications as functional materials. In this context, luminescent MOFs as fluorescence sensors have recently received significant attention for the sensing of ionic species and small molecules. In this work, a new luminescent heterometallic zinc(II)-barium(II)-based anionic metal-organic framework, namely poly[imidazolium [triaqua(μ ₆ -benzene-1,3,5-tricarboxylato)bariumtrizinc] tetrahydrate], {(C ₃ H ₄ N ₂ )[BaZn ₃ (C ₉ H ₃ O ₆ ) ₃ (H ₂ O) ₃ ]·4H ₂ O} _n (1), was synthesized under hydrothermal conditions and characterized. Compound 1 presents a three-dimensional framework with an unprecedented (3,5)-connected topology of the point symbol (3.9 ² ).(3 ³ .4 ² .5.9 ³ .10), and exhibits `turn-off' luminescence responses for the Cu ²⁺ and Fe ³⁺ ions in aqueous solution based on significantly different quenching mechanisms.