The tetradentate imino-carboxylate ligand L2- chelates the equatorial sites of NiII to give the complex Ni(L)(MeOH)2 in which a NiII center is bound in an octahedral coordination environment with ...MeOH ligands occupying the axial sites. Lanthanide (Ln) and Group II metal ions (M) template the aggregation of six Ni(L) fragments into the octahedral cage aggregates {MNi(L)6} x + (1: M = SrII; x = 2, 2: M = BaII; x = 2, 3: M = LaIII; x = 3, 4: M = CeIII; x = 3, 5: M = PrIII; x = 3, and 6: M = NdIII; x = 3). In the presence of Group I cations, however, aggregates composed of the alkali metal-oxide cations template various cage compounds. Thus, Na+ forms the trigonal bipyramidal Na5O3+ core within a tricapped trigonal prismatic Ni(L)9 aggregate to give {(Na5O)⊂Ni(L)9(MeOH)3}(BF4)2·OH·CH3OH, 7. Li+ and Na+ together form a mixed Li+/Na+ core comprising distorted trigonal bipyramidal Na3Li2O3+ within an approximately anti-square prismatic Ni(L)8 cage in {(Na3Li2O)⊂Ni(L)8(CH3OH)1.3(BF4)0.7}(BF4)2.3·(CH3OH)2.75·(C4H10O)0.5, 8, while in the presence of Li+, a tetrahedral Li4O2+ core within a hexanuclear open cage Ni(L)6 in {(Li4O)⊂Ni(L)6(CH3OH)3}2ClO4·1.85CH3OH, 9, is produced. In the presence of H2O, the Cs+ cation induces the aggregation of the Ni(L)(H2O)2 monomer to give the cluster Cs2Ni(L)(H2O)26·2I·4CH3OH·5.25H2O, 10. Analysis by electronic spectroscopy and mass spectrometry indicates that in solution the trend in stability follows the order 1−6 > 7 > 8 ∼ 9. Magnetic susceptibility data indicate that there is net antiferromagnetic exchange between magnetic centers within the cages.
The unique bifunctional porous metal-organic framework, Co(HL
dc
)·1.5MeOH·dioxane, incorporates both free-standing carboxyl and pyridyl groups within its pores. Gas adsorption measurements on the ...desolvated framework reveal unusual selective CO
2
adsorption over C
2
H
2
and CH
4
linked to a framework phase change from a narrow pore (
np
) to a large pore (
lp
) form, mediated by CO
2
uptake at 195 K. This phase transition has been monitored by
in situ
powder X-ray diffraction and IR spectroscopy, and modelled by Grand Canonical Monte Carlo simulations revealing that the reversible
np
to
lp
transition is linked to the rotation of pyridyl rings acting as flexible "pore gates".
A unique bifunctional porous metal-organic framework incorporating both free-standing carboxyl and pyridyl groups within its pore cavity is reported.
The cations Pd2Cl2L2+ and KL2′+ (L = 18aneN2S4, L′ =15aneO5) have been used as templates for the synthesis of unique three‐dimensional polyiodide networks. The metal cations in Pd2Cl2L1.5I5(I3)2 are ...linked into infinite chains by pairwise hydrogen bonding; the resulting cationic polymers run through channels formed by the extended polyiodide network. KL2′I9 shows a three‐dimensional network of puckered cubic cages of I9− ions whose cavities are occupied by the metal cations (section from the structure shown on the right).
This work reports the thermal and electron beam stabilities of a series of isostructural metal-organic frameworks (MOFs) of type MFM-300(M), where M = Al, Ga, In, or Cr. MFM-300(Cr) was most electron ...beam stable, 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, with the one-dimensional pore channels being the most stable, although 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.
Dieser Artikel untersucht mit Daten des SOEP 2016 (n=24.339) das von Holger Lengfeld gefundene Ergebnis, wonach Unterstutzung fur die AfD nicht mit niedrigen Statuslagen zu erklaren ist. Er zeigt, ...dass geringes Einkommen, Berufsprestige, Bildung und Arbeitslosigkeit AfD-Unterstutzung genauso wenig erklaren konnen, wie Unzufriedenheit mit dem eigenen Einkommen oder der allgemeinen Wohlstandsentwicklung. Daraufhin erweitert der Artikel Lengfelds Analyse, indem er zeigt, dass sich AfD-Wahler in Bezug auf sehr wenige Einstellungen von sonstigen Deutschen unterscheiden. Sie sind jedoch unzufrieden mit der Demokratie und machen sich starkere Sorgen um Kriminalitat und den sozialen Zusammenhalt, denn sie meinen, dass Fluchtlinge Deutschlands Kultur untergraben und Zuwanderung generell Anlass zur Sorge bereitet. AFD-Unterstutzer kommen somit aus allen gesellschaftlichen Schichten und Milieus und unterscheiden sich fast ausschließlich durch ihre Einstellungen zu Fluchtlingen und Zuwanderung.
The new angular bridging ligand 2,4′‐(1,4‐phenylene)bispyridine toposelectively forms dinuclear metallacycles with Cd(NO3)2 and Zn(NO3)2. The CdII helicates associate into an unprecedented ...three‐dimensional zeolite‐like helical coordination polymer with hexagonal hydrophobic channels with a diameter of about 10 Å (see scheme). These channels, initially occupied by uncoordinated ligand molecules, can be emptied to afford a guest‐free coordination polymer.
In Germany, the Occupational Safety Act requires every organization to employ or contract safety and health experts. The law calls for two kinds of experts: medical specialists on the one hand and ...safety professionals (Commonly referred to as “Sifa” in German) on the other. Aside from the general intra- and supra-company conditions and circumstances that shape the safety professional’s work, the development of personal (action) competences is crucial for effective prevention work. Every participant in the Sifa training program already has a wide range of different abilities and skills (competences) from their prior vocational training and career under their belts. The goal of the Sifa training program is to enable future safety professionals to perform their tasks effectively. Learning in the redesigned Sifa training program takes place with a real-world orientation. This also means that participants start using their new expertise at their current employer; reflecting on this experience helps consolidate their newly acquired competences.
