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Instruments / Technical Area	Publication Details	Published	Actions
I11-High Resolution Powder Diffraction	Increasing alkyl chain length in a series of layered metal–organic frameworks aids ultrasonic exfoliation to form nanosheets David J. Ashworth , Thomas M. Roseveare , Andreas Schneemann , Max Flint , Irene Dominguez Bernáldes , Pia Vervoorts , Roland A. Fischer , Lee Brammer , Jonathan A. Foster Inorganic Chemistry DOI: 10.1021/acs.inorgchem.9b01128 Show Abstract ▼ Abstract: Metal–organic framework nanosheets (MONs) are attracting increasing attention as a diverse class of two-dimensional materials derived from metal–organic frameworks (MOFs). The principles behind the design of layered MOFs that can readily be exfoliated to form nanosheets, however, remain poorly understood. Here we systematically investigate an isoreticular series of layered MOFs functionalized with alkoxy substituents in order to understand the effect of substituent alkyl chain length on the structure and properties of the resulting nanosheets. A series of 2,5-alkoxybenzene-1,4-dicarboxylate ligands (O2CC6H2(OR)2CO2, R = methyl–pentyl, 1–5, respectively) was used to synthesize copper paddle-wheel MOFs. Rietveld and Pawley fitting of powder diffraction patterns for compounds Cu(3–5)(DMF) showed they adopt an isoreticular series with two-dimensional connectivity in which the interlayer distance increases from 8.68 Å (R = propyl) to 10.03 Å (R = pentyl). Adsorption of CO2 by the MOFs was found to increase from 27.2 to 40.2 cm3 g–1 with increasing chain length, which we attribute to the increasing accessible volume associated with increasing unit-cell volume. Ultrasound was used to exfoliate the layered MOFs to form MONs, with shorter alkyl chains resulting in higher concentrations of exfoliated material in suspension. The average height of MONs was investigated by AFM and found to decrease from 35 ± 26 to 20 ± 12 nm with increasing chain length, with the thinnest MONs observed being only 5 nm, corresponding to five framework layers. These results indicate that careful choice of ligand functionalities can be used to tune nanosheet structure and properties, enabling optimization for a variety of applications.	Aug 2019
I19-Small Molecule Single Crystal Diffraction	Blending Gelators to Tune Gel Structure and Probe Anion-Induced Disassembly Jonathan A. Foster , Robert Edkins , Gary J. Cameron , Neil Colgin , Katharina Fucke , Sam Ridgeway , Andrew G. Crawford , Todd B. Marder , Andrew Beeby , Steven L. Cobb , Jonathan W. Steed Chemistry - A European Journal 20 (1), 279 - 291 DOI: 10.1002/chem.201303153 PMID: 24302604 Diamond Proposal Number(s): [6749] Open Access Show Abstract ▼ Abstract: Blending different low molecular weight gelators (LMWGs) provides a convenient route to tune the properties of a gel and incorporate functionalities such as fluorescence. Blending a series of gelators having a common bis-urea motif, and functionalised with different amino acid-derived end-groups and differing length alkylene spacers is reported. Fluorescent gelators incorporating 1- and 2-pyrenyl moieties provide a probe of the mixed systems alongside structural and morphological data from powder diffraction and electron microscopy. Characterisation of the individual gelators reveals that although the expected a-urea tape motif is preserved, there is considerable variation in the gelation properties, molecular packing, fibre morphology and rheological behaviour. Mixing of the gelators revealed examples in which: 1) the gels formed separate, orthogonal networks maintaining their own packing and morphology, 2) the gels blended together into a single network, either adopting the packing and morphology of one gelator, or 3) a new structure not seen for either of the gelators individually was created. The strong binding of the urea functionalities to anions was exploited as a means of breaking down the gel structure, and the use of fluorescent gel blends provides new insights into anion-mediated gel dissolution.	Jan 2014

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