Gezielte Positionierung metallorganischer Komplexfragmente in einem Calix[4]aren-Hohlraum

Chelated Bisphosphites with a Calix[4]arene Backbone: New Ligands for Rhodium-Catalyzed Low-Pressure Hydroformylation with Controlled Regioselectivity

“…Irurre, A. Fernandez-Serrat, M. Altayo, Enantiomer 1998, 3(2), 103 ± 120. [8] The polymers obtained with the previously used simple styryl TADDOL derivatives also showed such a decline. Chim.…”

“…[5] Calix [4]arenes are macrocycles that possess a conical molecular form with four, symmetrically located OH groups at the narrow edge of the cone. [8] We obtained 1 (Scheme 1), the first compound of a new class of chelate phosphites in which two phosphorus atoms each are bonded to two neighboring oxygen atoms of the Scheme 1. [7] Recently chelate phosphanes were reported in which the phosphorus atoms are located at the wide edge of the cone.…”

Kohlendioxid-Fixierung an Zweikernkomplexen mit hydrophoben Bindungstaschen

“…Sie wurden zur Stabilisierung von reaktiven Intermediaten, [1] für selektive organische Transformationen [2] oder als Katalysatoren für Reaktionen, die vom Reaktionsmedium abhängen, verwendet. Die meisten dieser Verbindungen sind einkernige Spezies.…”

“…[8] Da der Aqualigand durch die beiden Lewis-sauren Ni II -Zentren aktiviert wird, sollte die Deprotonierung von 5 zum bekannten m-OH-Komplex 3 stark begünstigt sein. (7) [1] Auf Polypeptiden basierende Bibliotheken benötigen Kodierungsstrategien, wie Phagen-, [2] Ribosomen- [3] oder mRNA-Display, [4] welche eine eindeutige Verknüpfung des Phänotyps mit dem Genotyp gewährleisten. Als nächstes Intermediat wurde ein Hydrogencarbonatkomplex vermutet.…”

Use of some calixarenes as cleaning agents for low radioactive contaminated waters

“…The differences are significant, since the yield of retention at 40~ is practically double as compared to that obtained at 4~ Only in the case of 137Cs+, the sorption capacity of the two calixarenes at 22~ is comparable to that at 40~ In all other cases, the differences between the yield of sorption at equilibrium have the approximate value of 0.5 meq radiocation retained per gram of calixarene for an increase in temperature of 10~ 3. p-(tert-butyl)calix [4]arene has a higher retention capacity than calix [4]arene, whatever the temperature and the sorbed radiocation. This behaviour can be explained by the presence of tert-butyl groups in para-position with two important consequences: -the inductive effect acting on the hydroxyl groups encourages deprotonation [ 11 ]; -the radiocations are "stuck" within the cavity formed by the association of four structural units, due to the presence of bulky tert-butyl groups [12][13][14]. 4.…”