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This work reports the thermal and electron beam stabilities of a series of isostructural metal–organic frameworks (MOFs) of type MFM-300(M) (M = Al, Ga, In, Cr). MFM-300(Cr) was most stable under the electron beam, having an unusually high critical electron fluence of 1111 e− Å−2 while the Group 13 element MOFs were found to be less stable. Within Group 13, MFM-300(Al) had the highest critical electron fluence of 330 e− Å−2, compared to 189 e− Å−2 and 147 e− Å−2 for the Ga and In MOFs, respectively. For all four MOFs, electron beam-induced structural degradation was independent of crystal size and was highly anisotropic, although both the length and width of the channels decreased during electron beam irradiation. Notably, MFM-300(Cr) was found to retain crystallinity while shrinking up to 10%. Thermal stability was studied using in situ synchrotron X-ray diffraction at elevated temperature, which revealed critical temperatures for crystal degradation to be 605, 570, 490 and 480 °C for Al, Cr, Ga, and In, respectively. The pore channel diameters contracted by ≈0.5% on desorption of solvent species, but thermal degradation at higher temperatures was isotropic. The observed electron stabilities were found to scale with the relative inertness of the cations and correlate well to the measured lifetime of the materials when used as photocatalysts. [ABSTRACT FROM AUTHOR]

We investigate the low-energy transitions (0-570 cm-1) of the S1 state of para-fluorotoluene (pFT) using a combination of resonance-enhanced multiphoton ionization and zero-kinetic-energy (ZEKE) spectroscopy and quantum chemical calculations. By using various S1 states as intermediate levels, we obtain ZEKE spectra. The differing activity observed allows detailed assignments to be made of both the cation and S1 low-energy levels. The assignments are in line with the recently published work on toluene from the Lawrance group [J. R. Gascooke et al., J. Chem. Phys. 143, 044313 (2015)], which considered vibration-torsion coupling in depth for the S1 state of toluene. In addition, we investigate whether two bands that occur in the range 390-420 cm-1 are the result of a Fermi resonance; we present evidence for weak coupling between various vibrations and torsions that contribute to this region. This work has led to the identification of a number of misassignments in the literature, and these are corrected. [ABSTRACT FROM AUTHOR]

Selective oxidation of benzylic C−H compounds to ketones is important for the production of a wide range of fine chemicals, and is often achieved using toxic or precious metal catalysts. Herein, we report the efficient oxidation of benzylic C−H groups in a broad range of substrates under mild conditions over a robust metal–organic framework material, MFM‐170, incorporating redox‐active [Cu2II(O2CR)4] paddlewheel nodes. A comprehensive investigation employing electron paramagnetic resonance (EPR) spectroscopy and synchrotron X‐ray diffraction has identified the critical role of the paddlewheel moiety in activating the oxidant tBuOOH (tert‐butyl hydroperoxide) via partial reduction to [CuIICuI(O2CR)4] species. [ABSTRACT FROM AUTHOR]

MFM‐300(Al) shows reversible uptake of NH3 (15.7 mmol g−1 at 273 K and 1.0 bar) over 50 cycles with an exceptional packing density of 0.62 g cm−3 at 293 K. In situ neutron powder diffraction and synchrotron FTIR micro‐spectroscopy on ND3@MFM‐300(Al) confirms reversible H/D site exchange between the adsorbent and adsorbate, representing a new type of adsorption interaction. High storage capacity: MFM‐300(Al) shows reversible uptake of NH3 over 50 cycles with an exceptional packing density of 0.62 g cm−3 at 293 K. Neutron diffraction and FTIR micro‐spectroscopy confirm reversible H/D site exchange between the adsorbent and adsorbate, representing a new type of adsorption interaction. [ABSTRACT FROM AUTHOR]

Porous MFM‐300(Al) can store and release ammonia gas at room temperature without degradation over 50 cycles of adsorption and release, as reported by S. Yang, M. Schröder, and co‐workers in their Communication on page 14778 ff. A high packing density of ammonia was observed, and in situ neutron powder diffraction and synchrotron FTIR micro‐spectroscopy of ND3@MFM‐300(Al) confirmed reversible H/D site exchange between the adsorbent and adsorbate, representing a new type of adsorption interaction in MOFs. [ABSTRACT FROM AUTHOR]

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Selective oxidation of benzylic C-H compounds to ketones is important for the production of a wide range of fine chemicals, and is often achieved using toxic or precious metal catalysts. Herein, we report the efficient oxidation of benzylic C-H groups in a broad range of substrates under mild conditions over a robust metal-organic framework material, MFM-170, incorporating redox-active [Cu 2 II (O 2 CR) 4 ] paddlewheel nodes. A comprehensive investigation employing electron paramagnetic resonance (EPR) spectroscopy and synchrotron X-ray diffraction has identified the critical role of the paddlewheel moiety in activating the oxidant t BuOOH (tert-butyl hydroperoxide) via partial reduction to [Cu II Cu I (O 2 CR) 4 ] species., (© 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

The efficient production of light olefins from renewable biomass is a vital and challenging target to achieve future sustainable chemical processes. Here we report a hetero-atomic MFI-type zeolite (NbAlS-1), over which aqueous solutions of γ-valerolactone (GVL), obtained from biomass-derived carbohydrates, can be quantitatively converted into butenes with a yield of >99% at ambient pressure under continuous flow conditions. NbAlS-1 incorporates simultaneously niobium(V) and aluminium(III) centres into the framework and thus has a desirable distribution of Lewis and Brønsted acid sites with optimal strength. Synchrotron X-ray diffraction and absorption spectroscopy show that there is cooperativity between Nb(V) and the Brønsted acid sites on the confined adsorption of GVL, whereas the catalytic mechanism for the conversion of the confined GVL into butenes is revealed by in situ inelastic neutron scattering, coupled with modelling. This study offers a prospect for the sustainable production of butene as a platform chemical for the manufacture of renewable materials.

MFM-300(Al) shows reversible uptake of NH 3 (15.7 mmol g -1 at 273 K and 1.0 bar) over 50 cycles with an exceptional packing density of 0.62 g cm -3 at 293 K. In situ neutron powder diffraction and synchrotron FTIR micro-spectroscopy on ND 3 @MFM-300(Al) confirms reversible H/D site exchange between the adsorbent and adsorbate, representing a new type of adsorption interaction., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We investigate the low-energy transitions (0-570 cm -1 ) of the S 1 state of para-fluorotoluene (pFT) using a combination of resonance-enhanced multiphoton ionization and zero-kinetic-energy (ZEKE) spectroscopy and quantum chemical calculations. By using various S 1 states as intermediate levels, we obtain ZEKE spectra. The differing activity observed allows detailed assignments to be made of both the cation and S 1 low-energy levels. The assignments are in line with the recently published work on toluene from the Lawrance group [J. R. Gascooke et al., J. Chem. Phys. 143, 044313 (2015)], which considered vibration-torsion coupling in depth for the S 1 state of toluene. In addition, we investigate whether two bands that occur in the range 390-420 cm -1 are the result of a Fermi resonance; we present evidence for weak coupling between various vibrations and torsions that contribute to this region. This work has led to the identification of a number of misassignments in the literature, and these are corrected.