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

• Published in: New journal of chemistry Vol. 44; no. 27; pp. 11829 - 11834
• Main Authors: Talha, Khalid, Alamgir, He, Tao, Xie, Lin-Hua, Wang, Bin, Zhao, Min-Jian, Zhang, Yong-Zheng, Chen, Qiang, Li, Jian-Rong
• Format: Journal Article
• Language: English
• Published: 13.07.2020
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d0nj02617d

A layer-pillared three-dimensional (3D) metal-organic framework (MOF) BUT-26 was synthesized from a two-dimensional (2D) MOF BUT-25 through single-crystal to single-crystal (SC-SC) transformation. Two honeycomb-shaped layers were linked by formate ions forming a bilayer structure of BUT-25 . The formate pillar was then exchanged by the subsequently added ligand thiophene-2,5-dicarboxylic acid (H 2 TDC), which successfully stitched the 2D layers of BUT-25 into 3D BUT-26 without disturbing the original honeycomb-shaped layers. Interestingly, BUT-26 with free nitrogen and oxygen sites proved to be a highly sensitive MOF-based sensor with a limit of detection (LOD) of 0.12 μM and 0.1 μM 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 that BUT-26 can be used for colorimetric sensing of both ions. BUT-26 , synthesized via a ligand exchange reaction, can detect trace amounts of Cu 2+ and Fe 3+ ions in aqueous solutions.