Luminescent Metal-Organic Framework with Outstanding "Turn-On" Hg2+ Sensing Ability First Constructed by an AIE Ligand

Jinfang Zhang; Xingyu Tao; Yinlong Yue; Dejing Yin; Chi Zhang

doi:10.1021/acs.inorgchem.4c04672

Luminescent Metal-Organic Framework with Outstanding "Turn-On" Hg²⁺ Sensing Ability First Constructed by an AIE Ligand

Inorg Chem. 2025 Jan 13;64(1):335-343. doi: 10.1021/acs.inorgchem.4c04672. Epub 2024 Dec 30.

Authors

Jinfang Zhang¹, Xingyu Tao¹, Yinlong Yue¹, Dejing Yin², Chi Zhang^{1

3}

Affiliations

¹ International Joint Research Center for Photoresponsive Molecules and Materials, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, P. R. China.
² School of Biotechnology, Jiangnan University, Wuxi 214122, P. R. China.
³ School of Chemical Science and Engineering, Tongji University, Shanghai 200092, P. R. China.

PMID: 39801388
DOI: 10.1021/acs.inorgchem.4c04672

Abstract

Hg²⁺ is highly toxic and can cause serious harm to the environment and humans. Thus, it is vital to develop efficient Hg²⁺ sensors. In this work, a LMOF-based (LMOF = luminescent metal-organic framework) "turn-on" Hg²⁺ sensor (1) is first developed by an aggregation-induced emission (AIE) functional ligand. 1 with a formula of [Cd₃(L)₂(NDA)₃(H₂O)₂·(L)(MeOH)]_n (L = 4,4'-((2,7-di-tert-butyl-9H-fluoren-9-ylidene)-methylene)dipyridine; H₂NDA = 1,4-naphthalenedicarboxylic acid) exhibits a unique (3,4)-connected 2-D framework with 3-connected Cd1, 4-connected [Cd₂(COO)₃]⁺ cluster, and L and NDA^2- bridges. The fluorene rings of L in 1 stack in a back-to-back manner. 1 has excellent water, pH, and thermal stabilities and can "turn-on" detect Hg²⁺ with ultrahigh sensitivity, good selectivity, and recyclability in a water medium. Furthermore, 1 shows obvious naked-eye-visible emission change and an extremely fast sensing response toward Hg²⁺ (<1 S) and can maintain its enhanced intensity over 5 min. The test paper is developed for practical "turn-on" Hg²⁺ sensing application. The "turn-on" Hg²⁺ sensing mechanism of 1 is discussed in detail.