A New Molecular Recognition Concept: Multiple Hydrogen Bonds and Their Optically Triggered Proton Transfer in Confined Metal-Organic Frameworks for Superior Sensing Element

Jiao Lei; Bingqiang Wang; Yong-Peng Li; Wen-Juan Ji; Ke Wang; Honglan Qi; Pi-Tai Chou; Miao-Miao Zhang; Hongtao Bian; Quan-Guo Zhai

doi:10.1021/acsami.1c03410

A New Molecular Recognition Concept: Multiple Hydrogen Bonds and Their Optically Triggered Proton Transfer in Confined Metal-Organic Frameworks for Superior Sensing Element

ACS Appl Mater Interfaces. 2021 May 19;13(19):22457-22465. doi: 10.1021/acsami.1c03410. Epub 2021 May 10.

Authors

Affiliations

¹ Key Laboratory of Macromolecular Science of Shaanxi Province, Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710062, China.
² Key Laboratory of Magnetic Molecules & Magnetic Information, Materials Ministry of Education, School of Chemistry & Material Science, Shanxi Normal University, Linfen, Shanxi 041004, China.
³ Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.

PMID: 33970593
DOI: 10.1021/acsami.1c03410

Abstract

We report a new sensing mechanism based on an indium-dihydroxyterephthalic acid metal-organic framework (MOF, SNNU-153), in which the spatially fitted analyte-MOF hydrogen-bond (H-bond) formation provides selective recognition while the analyte-H-bond assisted excited-state intramolecular proton transfer (ESIPT) and the resulting ratiometric emission act as a superior signal transducer with ultrafast response. The synergy of ESIPT signal transduction and confined MOF pore enables the SNNU-153 sensor selectively sensing hydrazine even among nitrogen-containing hydride analogs such as NH₃, NH₂OH, and (Me)₂NNH₂. The key of H-bond and associated ESIPT was further counter evidenced by an indium-2,5-dimethoxyterephthalic acid MOF (SNNU-152), where the hydroxyl protons were removed by methylation, showing near inertness to N₂H₄. The new molecular recognition concept thus makes SNNU-153 a powerful N₂H₄ sensor, which should be far-reaching to other sensing elements.

Keywords: confined space; excited-state intramolecular proton transfer (ESIPT); hydrazine identification; metal−organic frameworks (MOFs); ratiometric fluorescence sensor.