Metal Hydrogen-Bonded Organic Framework Constructed by an Aggregation-Caused-Quenching Fluorophore, but Achieving
Jinfang Zhang1, Jiamin Wang1, Shuaixing Wang1
1International Joint Research Center for Photoresponsive Molecules and Materials, School of Chemical and Material Engineering, Jiangnan University, Wuxi214122, P. R. China.
Abstract:
Strong acid/base wastewater and acidic MnO4- solutions pose severe environmental risks. This demands the development of efficient materials for sensing them. Herein, a unique metal hydrogen-bonded organic framework (M-HOF) {[Cd(BTC)(H2BTC)]·(H2L)}n (1; H3BTC = 1,3,5-Benzenetricarboxylic acid) is achieved by an ACQ-featured (aggregation-caused quenching) organic unit, 2,7-di(pyridin-4-yl)-9H-carbazole (L), for efficient sensing application. 1 is fabricated by 1-D metal-organic anionic double-stranded chains and N-protonated cationic H2L2+ organic units through hydrogen bonds and π-π stacking interactions. More importantly, 1 has superior sensing performance toward strong acid, strong base, and acidic MnO4- solutions. 1 exhibits "turn-on" (fluorescence shift and enhancement) sensing responses to strong acid and base. Its fluorescence enhancement can reach 6.9-fold and 3.7-fold, respectively. This represents the first ACQ-fluorophore-based "turn-on" sensor in the M-HOF system and provides a new approach to construct strong acid-base-response materials. Furthermore, 1' (acid-pretreated 1) enables the rare acid-systemic MnO4- fluorescence quenching detection with a very low limit of detection (1.41 μM). This work provides a promising approach to develop efficient and convenient sensors for strong acidic and basic environments.
