TY - JOUR
T1 - A pH-Sensing Fluorescent Metal-Organic Framework
T2 - PH-Triggered Fluorescence Transition and Detection of Mycotoxin
AU - Yang, Shuai Liang
AU - Liu, Wan Shan
AU - Li, Gen
AU - Bu, Ran
AU - Li, Peng
AU - Gao, En Qing
N1 - Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/10/19
Y1 - 2020/10/19
N2 - Due to its great relevance to environmental, biological, and chemical processes, the precise detection of pH or acidic/basic species is an ongoing and imperative need. In this context, pH-sensitive luminescent systems are highly desired. We reported a three-dimensional Zn(II) MOF synthesized from a bipyridyl-tetracarboxylic ligand and composed of 4-fold interpenetrated diamond frameworks. Because the steric hindrance in the ligand prevents metal coordination with the pyridyl group, the MOF features free basic N sites accessible to the small H+ ions, which renders pH responsivity. The aqueous dispersion exhibits an abrupt, high-contrast, and reversible on-off fluorescence transition in the narrow pH range of 5.4-6.2. The sensitive bistable system can be used for the precise monitoring of pH within the range and for use as a pH-triggered optical switch. The responsive mechanism through pyridyl protonation is collaboratively supported by data fitting, absorption spectra, and molecular orbital calculations. In particular, spectral and theoretical analyses reveal the destruction of n → π* transitions and the appearance of intramolecular charge-transfer transitions upon pyridyl protonation. Moreover, by virtue of the pH-responsive fluorescence, the MOF shows appealing sensing performance for the detection of 3-nitropropionic acid, a major mycotoxin in moldy sugar cane.
AB - Due to its great relevance to environmental, biological, and chemical processes, the precise detection of pH or acidic/basic species is an ongoing and imperative need. In this context, pH-sensitive luminescent systems are highly desired. We reported a three-dimensional Zn(II) MOF synthesized from a bipyridyl-tetracarboxylic ligand and composed of 4-fold interpenetrated diamond frameworks. Because the steric hindrance in the ligand prevents metal coordination with the pyridyl group, the MOF features free basic N sites accessible to the small H+ ions, which renders pH responsivity. The aqueous dispersion exhibits an abrupt, high-contrast, and reversible on-off fluorescence transition in the narrow pH range of 5.4-6.2. The sensitive bistable system can be used for the precise monitoring of pH within the range and for use as a pH-triggered optical switch. The responsive mechanism through pyridyl protonation is collaboratively supported by data fitting, absorption spectra, and molecular orbital calculations. In particular, spectral and theoretical analyses reveal the destruction of n → π* transitions and the appearance of intramolecular charge-transfer transitions upon pyridyl protonation. Moreover, by virtue of the pH-responsive fluorescence, the MOF shows appealing sensing performance for the detection of 3-nitropropionic acid, a major mycotoxin in moldy sugar cane.
UR - https://www.scopus.com/pages/publications/85093705372
U2 - 10.1021/acs.inorgchem.0c02419
DO - 10.1021/acs.inorgchem.0c02419
M3 - 文章
C2 - 33022178
AN - SCOPUS:85093705372
SN - 0020-1669
VL - 59
SP - 15421
EP - 15429
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 20
ER -