A unique zinc-organic framework constructed through in situ ligand synthesis for conversion of CO₂under mild conditions and as a luminescence sensor for Cr₂O₇²⁻/CrO₄²⁻

Abstract

A novel zinc-organic framework, {[Zn₃(tza)₂(μ₂-OH)₂(H₂O)₂]·H₂O}_n (1) (H₂tza = 1H-tetrazolate-5-acetic acid), was synthesized through an in situ generated tetrazole ligand under hydrothermal conditions. In compound 1, tza^2- ligands and Zn²⁺ are interlinked to form 2D layers, which are further pillared through μ₂-OH groups to generate a 3D framework. Thermogravimetric analysis and powder X-ray diffraction confirm that 1 has high thermal stability, pH stability and solvent stability. Catalytic studies show that 1 exhibits excellent catalytic ability for the cycloaddition of CO₂ with epoxides under 50 °C and 0.1 MPa. Importantly, 1 can be reused at least six times. Furthermore, luminescence investigations indicate that 1 can serve as a recyclable luminescence sensor to efficiently detect Cr₂O₇^2-/CrO₄^2-, and the detection limit can reach 10^-6 mol L^-1 and 4 × 10^-6 mol L^-1, respectively.