Modulator-controlled synthesis of microporous STA-26, an interpenetrated 8,3-connected zirconium MOF with the the-i topology, and its reversible lattice shift

The authors acknowledge the support of the EPSRC/St Andrews Criticat CDT (RRRP, PAW) and the European Community Seventh Framework Program (FP7/2007-2013) number 608490 (project M4CO2) (KKC, MYM, KIH, PAW). SEA would like to thank the Royal Society and Wolfson Foundation for a merit award. This research made use of the Balena High Performance Computing (HPC) Service at the University of Bath. The research data (and/or materials) supporting this publication can be accessed at DOI: http://dx.doi.org/10.17630/6ffeed8a-e75f-4648-968f-3ed32a94e9a0.A fully interpenetrated 8,3-connected zirconium MOF with the the-i topology type, STA-26 (St Andrews porous material-26), has been prepared using the 4,4',4"-(2,4,6-trimethylbenzene-1,3,5-triyl)tribenzoate (TMTB) tritopic linker with formic acid as a modulating agent. In the as-prepared form STA-26 possesses Im-3m symmetry compared with the Pm-3m symmetry of the non-interpenetrated analogue, NU-1200, prepared using benzoic acid as a modulator. Upon removal of residual solvent there is a shift between the interpenetrating lattices and a resultant symmetry change to Cmcm which is fully reversible. This is observed by X-ray diffraction and 13C MAS NMR is also found to be remarkably sensitive to the structural transition. Furthermore, heating STA-26(Zr) in vacuum dehydroxylates the Zr6 nodes leaving coordinatively unsaturated Zr4+ sites, as shown by IR spectroscopy using CO and CD3CN as probe molecules. Nitrogen adsorption at 77 K together with grand canonical Monte Carlo simulations confirms a microporous, fully interpenetrated, structure with pore volume 0.53 cm3 g−1 while CO2 adsorption at 196 K reaches 300 cm3 STP g−1 at 1 bar. While the pore volume is smaller than that of its non-interpenetrated mesoporous analogue, interpenetration makes the structure more stable to moisture adsorption and introduces shape selectivity in adsorption.PostprintPeer reviewe

A global experiment on motivating social distancing during the COVID-19 pandemic

Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges

Adsorption Forms of CO₂ on MIL-53(Al) and NH₂-MIL-53(Al) As Revealed by FTIR Spectroscopy

Adsorption of CO2 on MIL-53(Al) and NH2-MIL-53(Al) has been studied by Fourier transform infrared (FTIR) spectroscopy at different temperatures and equilibrium pressures. For better interpretation of the spectra 13CO2 was also utilized. It is established that with both samples at low coverages CO2 forms O-bonded complexes with the structural OH groups (OH⋯O12CO). These species are characterized by μ3(12CO2) at 2337-2338 cm-1 and two μ2(12CO2) modes around 662 and 650 cm-1. Simultaneously, the μ(OH) modes of the hydroxyl groups are red-shifted, while the δ(OH) modes are blue-shifted. At higher coverages (OH⋯O12CO)2 dimeric species are formed and this leads to a decrease of the μ3(CO2) frequency by 2-4 cm-1. This change is due to vibrational interaction as proven by the observation that the frequency remains practically unaffected for (OH⋯O12CO) (OH⋯O13CO) dimeric species. Interaction between dimers leads to additional slight decrease of the value of μ3(CO2). In parallel with the CO2 adsorption a partial transformation of the material from large-pore to narrow-pore form occurs. Far before CO2 interacts with all hydroxyl groups, polymeric CO2 species are produced within the MIL-53(Al) sample. They are characterized by a split μ3(CO2) mode with a pronounced component at 2340 cm-1. The formation of these species involves some of the dimers and is accompanied by a reopening of the MIL-53 structure. Analysis of the shift of the OH modes led to the conclusion that the polymeric moiety interacts strongly with one OH group and more weakly with several other hydroxyls. No polymeric species were observed with the NH2-MIL-53(Al) sample which is associated with the more stable narrow-pore structure of this material. However, evidence of interaction between CO2 and the hydroxyls H-bonded to amino groups was found.ChemE/Catalysis Engineerin