A three-dimensional metal-organic framework with high performance of dual cation sensing synthesizedviasingle-crystal transformation

摘要

A layer-pillared three-dimensional (3D) metal-organic framework (MOF)BUT-26was synthesized from a two-dimensional (2D) MOFBUT-25through single-crystal to single-crystal (SC-SC) transformation. Two honeycomb-shaped layers were linked by formate ions forming a bilayer structure ofBUT-25. The formate pillar was then exchanged by the subsequently added ligand thiophene-2,5-dicarboxylic acid (H2TDC), which successfully stitched the 2D layers ofBUT-25into 3DBUT-26without disturbing the original honeycomb-shaped layers. Interestingly,BUT-26with free nitrogen and oxygen sites proved to be a highly sensitive MOF-based sensor with a limit of detection (LOD) of 0.12 mu M and 0.1 mu M for Cu(2+)and Fe(3+)ions, respectively. These LOD results are much lower than the minimum values of these ions in drinking water specified by the US-EPA. Sensitive detection accompanied by a visible color change in the solution and solid phase confirms thatBUT-26can be used for colorimetric sensing of both ions.