The Nature of Structural Defects in ZIF-8 Revealed with <sup>1</sup>H and <sup>31</sup>P MAS NMR and X-Ray Absorption Spectroscopy
Issued Date
2024-01-01
Resource Type
ISSN
14337851
eISSN
15213773
Scopus ID
2-s2.0-85207750528
Journal Title
Angewandte Chemie - International Edition
Rights Holder(s)
SCOPUS
Bibliographic Citation
Angewandte Chemie - International Edition (2024)
Suggested Citation
Gabrienko A.A., Chaemchuen S., Kou Z., Ogiwara N., Kitagawa H., Khudozhitkov A.E., Stepanov A.G., Kolokolov D.I., Verpoort F. The Nature of Structural Defects in ZIF-8 Revealed with <sup>1</sup>H and <sup>31</sup>P MAS NMR and X-Ray Absorption Spectroscopy. Angewandte Chemie - International Edition (2024). doi:10.1002/anie.202414823 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/101915
Title
The Nature of Structural Defects in ZIF-8 Revealed with <sup>1</sup>H and <sup>31</sup>P MAS NMR and X-Ray Absorption Spectroscopy
Corresponding Author(s)
Other Contributor(s)
Abstract
The metal–organic frameworks (MOFs) attract interest as potential catalysts whose catalytic properties are driven by defects. Several methods have been proposed for the defects-inducing synthesis of MOFs. However, the active species formed on the defective sites remain elusive and uncharacterized, as the spectroscopic fingerprints of these species are hidden by the regular structure signals. In this work, we have performed the synthesis of ZIF-8 MOF with defect-inducing procedures using fully deuterated 2-methylimidazolate ligands to enhance the defective sites′ visibility. By combining 1H and 31P MAS NMR spectroscopy and X-ray absorption spectroscopy, we have found evidence for the presence of different structural hydroxyl Zn−OH groups in the ZIF-8 materials. It is demonstrated that the ZIF-8 defect sites are represented by Zn−OH hydroxyl groups with the signals at 0.3 and −0.7 ppm in the 1H MAS NMR spectrum. These species are of basic nature and may be responsible for the catalytic activity of the ZIF-8 material.