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Ultrasonic Exfoliation of Hydrophobic and Hydrophilic Metal–Organic Frameworks To Form Nanosheets
Author(s) -
Ashworth David J.,
Cooper Adam,
Trueman Mollie,
AlSaedi Rasha W. M.,
Smith Liam D.,
Meijer Anthony J. H. M.,
Foster Jonathan A.
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201803221
Subject(s) - exfoliation joint , materials science , nanoscopic scale , dispersion (optics) , aqueous solution , metal , metal organic framework , solvent , chemical engineering , intramolecular force , nanotechnology , organic chemistry , chemistry , graphene , metallurgy , physics , engineering , optics , adsorption
The modular structure of metal–organic framework nanosheets (MONs) provides a convenient route to creating two‐dimensional materials with readily tuneable surface properties. Here, the liquid exfoliation of two closely related layered metal–organic frameworks functionalised with either methoxy‐propyl ( 1 ) or pentyl ( 2 ) pendent groups intended to bestow either hydrophilic or hydrophobic character to the resulting nanosheets is reported. Exfoliation of the two materials in a range of different solvents highlighted significant differences in their dispersion properties, as well as their molecular and nanoscopic structures. Exchange or loss of solvent was found to occur at the labile axial position of the paddle‐wheel based MONs and DFT calculations indicated that intramolecular coordination by the oxygen of the methoxy‐propyl pendant groups may take place. The nanoscopic dimensions of the MONs were further tuned by varying the exfoliation conditions and through “liquid cascade centrifugation”. Aqueous suspensions of the nanosheets were used as sensors to detect aromatic heterocycles with clear differences in binding behaviour observed and quantified.