TY - JOUR
T1 - Temperature-Dependent Emission and Turn-Off Fluorescence Sensing of Hazardous "quat" Herbicides in Water by a Zn-MOF Based on a Semi-Rigid Dibenzochrysene Tetraacetic Acid Linker
AU - Mukhopadhyay, Arindam
AU - Jindal, Swati
AU - Savitha, Govardhan
AU - Moorthy, Jarugu Narasimha
N1 - Funding Information:
J.N.M. is thankful to the Science and Engineering Research Board (grant number SB/S2/JCB-52/2014) in New Delhi for generous funding through a J. C. Bose fellowship. A.M. and S.J. gratefully acknowledge the Council of Scientific and Industrial Research (CSIR, SRF) and Ministry of Human Resource Development (MHRD, GATE), New Delhi, respectively, for their research fellowships. We thank Mr. M. S. Krishna for his contributions in the initial stages during the synthesis of the linker.
Publisher Copyright:
Copyright © 2020 American Chemical Society.
PY - 2020/5/4
Y1 - 2020/5/4
N2 - A zinc metal-organic framework, i.e., Zn-MOF (Zn-DBC), with ca. 27% solvent-accessible void volume was synthesized from a rationally designed tetraacid based on sterically insulated dibenzo[g,p]chrysene core; the latter inherently features concave shapes. Due to rigidification of the fluorophore in the MOF, Zn-DBC exhibits a respectable fluorescence quantum yield of ca. 30% in the solid state. The fluorescent and water-stable Zn-DBC MOF was found to display intriguing temperature-dependent emission behavior with an activation barrier of 1.06 kcal/mol for radiationless deactivation from the singlet-excited state. It is shown that the Zn-MOF can be employed as an efficient sensory material for detection of hazardous "quat" dicationic herbicides in water by diffusion-limited "turn-off" fluorescence. Due to confinement of the cationic guest analytes within the pores of the MOF, the fluorescence quenching via excited-state charge transfer mechanism is shown to depend on the molecular size of the analyte in addition to the redox potentials. Remarkably, Zn-DBC permits sensing of DQ, a well-known toxic "quat" herbicide, with a detection limit as low as 2.8 ppm in water. The unique structural attributes of the Zn-MOF for highly efficient fluorescence sensing of toxic herbicides in water are thus exemplified for the first time.
AB - A zinc metal-organic framework, i.e., Zn-MOF (Zn-DBC), with ca. 27% solvent-accessible void volume was synthesized from a rationally designed tetraacid based on sterically insulated dibenzo[g,p]chrysene core; the latter inherently features concave shapes. Due to rigidification of the fluorophore in the MOF, Zn-DBC exhibits a respectable fluorescence quantum yield of ca. 30% in the solid state. The fluorescent and water-stable Zn-DBC MOF was found to display intriguing temperature-dependent emission behavior with an activation barrier of 1.06 kcal/mol for radiationless deactivation from the singlet-excited state. It is shown that the Zn-MOF can be employed as an efficient sensory material for detection of hazardous "quat" dicationic herbicides in water by diffusion-limited "turn-off" fluorescence. Due to confinement of the cationic guest analytes within the pores of the MOF, the fluorescence quenching via excited-state charge transfer mechanism is shown to depend on the molecular size of the analyte in addition to the redox potentials. Remarkably, Zn-DBC permits sensing of DQ, a well-known toxic "quat" herbicide, with a detection limit as low as 2.8 ppm in water. The unique structural attributes of the Zn-MOF for highly efficient fluorescence sensing of toxic herbicides in water are thus exemplified for the first time.
UR - https://www.scopus.com/pages/publications/85083825085
U2 - 10.1021/acs.inorgchem.0c00307
DO - 10.1021/acs.inorgchem.0c00307
M3 - Article
C2 - 32294375
AN - SCOPUS:85083825085
SN - 0020-1669
VL - 59
SP - 6202
EP - 6213
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 9
ER -