13C pNMR of “crumple zone” Cu(II) isophthalate metal-organic frameworks
Abstract
NMR spectroscopy of paramagnetic materials (pNMR) has the potential to provide great structural insight, but many challenges remain in interpreting the spectra in detail. This work presents a study of a series of structurally analogous metal-organic frameworks (MOFs) based on 5-substituted isophthalate linkers and Cu(II) paddlewheel dimers, of interest owing to their “crumple zone” structural rearrangement on dehydration/rehydration. 13C MAS NMR spectra of the MOFs reveal a wide variation in the observed resonance position for chemically similar C species in the different MOFs but, despite this, resonances are overlapped in several cases. However, by considering a combination of the integration of quantitative spectra, the resonance position as a function of temperature and T1 relaxation measurements, the spectra can be fully assigned. It is also demonstrated that the prototypical MOF in this series, STAM-1, displays a similar crumple zone rearrangement on dehydration to the well-characterised 5-ethoxyisophthalate MOF (STAM-17-OEt) although, while the materials have similar local C environments, dehydrated STAM-1 exhibits less long-range order.
Citation
Dawson , D M , Sansome , C E F , McHugh , L N , McPherson , M J , McCormick McPherson , L J , Morris , R E & Ashbrook , S E 2019 , ' 13 C pNMR of “crumple zone” Cu(II) isophthalate metal-organic frameworks ' , Solid State Nuclear Magnetic Resonance , vol. In press . https://doi.org/10.1016/j.ssnmr.2019.05.005
Publication
Solid State Nuclear Magnetic Resonance
Status
Peer reviewed
ISSN
0926-2040Type
Journal article
Description
SEA thanks the Royal Society and Wolfson Foundation for a merit award. REM and LNM thank the EPSRC for support (EP/N50936X/1).Collections
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