Catalytic properties of pristine and defect-engineered Zr-MOF-808 metal organic frameworks

[EN] Various defect-engineered Zr-trimesate MOF-808 compounds (DE-MOF-808) have been prepared by mixing the tricarboxylate ligands with dicarboxylate ligands; viz. isophthalate, pyridine-3,5-dicarboxylate, 5-hydroxy-isophthalate, or 5-amino-isophthalate. The resulting mixed-ligand compounds, MOF-808-X (X = IP, Pydc, OH or NH2) were all found to be highly crystalline and isostructural to the unmodified MOF-808. Pristine MOF-808 showed better catalytic performance than a UiO-66 reference compound for the Meerwein-Ponndorf-Verley (MPV) reduction of carbonyl compounds. This was attributed to a higher availability of coordinatively unsaturated Zr4+ sites (cus) in MOF-808 upon removal of formate ions. Meanwhile, cus in UiO-66 are only located at defect sites and are thus much less abundant. Further improvement of the catalytic activity of defect-engineered MOF-808-IP and MOF-808-Pydc was observed, which may be related with the occurrence of less crowded Zr4+ sites in DE-MOF-808. The wider pore structure of MOF-808 with respect to UiO-66 compounds translates into a sharp improvement of the activity for the MPV reduction of bulky substrates, as shown for estrone reduction to estradiol. Interestingly, MOF-808 produces a notable diastereoselectivity towards the elusive 17--hydroxy estradiol.This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 641887 (project acronym: DEFNET). Financial support from the Spanish Ministry of Economy and Competitiveness (program Severo Ochoa SEV20120267), the Spanish Ministry of Science and Innovation (project MAT2014-52085-C2-1-P), and the German Research Foundation (project KA 1698/19-1) is also gratefully acknowledged. The Microscopy Service of the Universitat Politecnica de Valencia are gratefully acknowledged for the SEM images.Mautschke, H.; Drache, F.; Senkovska, I.; Kaskel, S.; Llabrés I Xamena, FX. (2018). Catalytic properties of pristine and defect-engineered Zr-MOF-808 metal organic frameworks. Catalysis Science & Technology. 8(14):3610-3616. https://doi.org/10.1039/c8cy00742jS3610361681

Experimental validation of a self-calibrating cryogenic mass flowmeter

The Karlsruhe Institute of Technology (KIT) and the WEKA AG jointly develop a commercial flowmeter for application in helium cryostats. The flowmeter functions according to a new thermal measurement principle that eliminates all systematic uncertainties and enables self-calibration during real operation. Ideally, the resulting uncertainty of the measured flow rate is only dependent on signal noises, which are typically very small with regard to the measured value. Under real operating conditions, cryoplant-dependent flow rate fluctuations induce an additional uncertainty, which follows from the sensitivity of the method. This paper presents experimental results with helium at temperatures between 30 and 70 K and flow rates in the range of 4 to 12 g/s. The experiments were carried out in a control cryostat of the 2 kW helium refrigerator of the TOSKA test facility at KIT. Inside the cryostat, the new flowmeter was installed in series with a Venturi tube that was used for reference measurements. The measurement results demonstrate the self-calibration capability during real cryoplant operation. The influences of temperature and flow rate fluctuations on the self-calibration uncertainty are discussed

Global public policy, transnational policy communities, and their networks

Public policy has been a prisoner of the word "state." Yet, the state is reconfigured by globalization. Through "global public–private partnerships" and "transnational executive networks," new forms of authority are emerging through global and regional policy processes that coexist alongside nation-state policy processes. Accordingly, this article asks what is "global public policy"? The first part of the article identifies new public spaces where global policies occur. These spaces are multiple in character and variety and will be collectively referred to as the "global agora." The second section adapts the conventional policy cycle heuristic by conceptually stretching it to the global and regional levels to reveal the higher degree of pluralization of actors and multiple-authority structures than is the case at national levels. The third section asks: who is involved in the delivery of global public policy? The focus is on transnational policy communities. The global agora is a public space of policymaking and administration, although it is one where authority is more diffuse, decision making is dispersed and sovereignty muddled. Trapped by methodological nationalism and an intellectual agoraphobia of globalization, public policy scholars have yet to examine fully global policy processes and new managerial modes of transnational public administration

James F. Hazard Interview

Typed summary of interview with Hiram Drache concerning the Cooper Ranch with some mention of livestock and farm operations, the Cooper family, and Charles Houghton, Hazard's father-in-law

Investigations structurales des composés K

Dans un article récent, Knop et al(1) ont présenté un catalogue des techniques de synthèse des halogénures doubles d’indium et d’alcalins et de leurs structures, et ont détaillé une analyse des facteurs responsables des variations des longueurs des liaisons In-Cl. Nos travaux antérieurs sur les chloroindates de potassium sont repris dans cette comparaison et la redétermination de la structure de K3InCl6, H2O confirme notre description(2) dans le groupe d’espace 14 mm (Z = 14) et corrobore l’existence d’une isomérisation ionique dans le cristal : [math] → [math] + Cl-.Nous présentons ici les différents composés rencontrés dans la famille des bromoindates de potassium(2), où la coordinence de l’atome central passe de six dans K3InBr6, 1.5H2O ; K2(InBr5 H2O) ; K(InBr4(H2O)2), à quatre dans KInBr4.Nous résumons dans cette étude, les caractéristiques cristallographiques des deux premiers membres de la famille dont les structures ont été affinées par isotypie avec leurs homologues chlorés(2,4). Nous proposons une comparaison des longueurs des liaisons In-Br en fonction de la coordinence de l’atome central d’une part, et en fonction du degré de substitution des ligands halogènes par des ligands neutres H2O d’autre part

Investigations structurales des composés K

Les halogénoindates de Potassium ont en spectrométrie Raman, des spectres vibrationnels de très basses fréquences, permettant néanmoins une identification formelle(1). La connaissance de la structure X des bromoindates de potassium (Part. I) associée aux études similaires que nous avons réalisées sur leurs homologues chlorés (dans lesquelles nous exposons une analyse détaillée des interactions(2,3)), ainsi qu’aux mesures de taux de dépolarisation des bandes sur des monocristaux de K3InBr6, 1,5H2O et de K2(InBr5 H2O), facilitent l’attribution des modes de vibration observés. Pour les autres formes hydratées du diagramme InBr3-KBr-H2O, une localisation des principaux modes internes est proposée