Search results for "ether"
showing 10 items of 986 documents
Tall Tales for a Mass Audience: Dutch Penny Prints and Spanish Aleluyas in Comparative Perspective
2021
Abstract In this article we compare Dutch penny prints with Spanish Aleluyas, focusing on three specific functions of this premodern mass medium: popularising and adapting theatre plays; standardising (folk/fairy) tales; adapting and popularising literary classics. Via these functions we address the discrepancies between the two countries considering the materiality of the penny prints, the growth of the production, but also the transition from a predominantly religious, towards a more profane content. Striking was the lack of educative and edifying initiatives in Spain in contrast to the Dutch ideological strategies. We observed some interesting similarities as well. Although in both count…
Problemi di giurisdizione nel contrasto al traffico di migranti via mare
2018
I trafficanti di esseri umani si avvalgono con sempre più insistenza di ben collaudati protocolli operativi. Questi ultimi consentono loro di sottrarsi alla giurisdizione penale italiana che non si radica qualora – in ossequio ai criteri di cui all’art. 6 c.p.ed in conformità alla Convenzione sull’Alto Mare– l’azione illecita avvenga in acque internazionali.Così, premesse alcune linee concettuali sui limiti spaziali alla efficacia della legge penale, l’indagine si sofferma sulla soluzione ermeneutica offerta dallaCassazione che, apparentemente in modo sbrigativo e per esigenze di effettività della risposta punitiva, ha fatto ricorso alla controversa figura dell’autore mediato per sanzionare condott…
Quasi-Lie Brackets and the Breaking of Time-Translation Symmetry for Quantum Systems Embedded in Classical Baths
2018
Many open quantum systems encountered in both natural and synthetic situations are embedded in classical-like baths. Often, the bath degrees of freedom may be represented in terms of canonically conjugate coordinates, but in some cases they may require a non-canonical or non-Hamiltonian representation. Herein, we review an approach to the dynamics and statistical mechanics of quantum subsystems embedded in either non-canonical or non-Hamiltonian classical-like baths which is based on operator-valued quasi-probability functions. These functions typically evolve through the action of quasi-Lie brackets and their associated Quantum-Classical Liouville Equations, or through quasi-Lie brackets a…
New Carbaalanes − (AlMe)8(CCH2Me)5(C≡C−Me) and the THF Adduct (AlMe)8(CCH2Me)5H·2THF
2001
The hydroalumination of Me2Al−C≡C−Me with a large excess of Me2AlH afforded the arachno-carbaalane (AlMe)8(CCH2Me)5H (4) by the release of AlMe3. 4 is almost insoluble in noncoordinating solvents and could not be purified by recrystallization. On an attempt to recrystallize 4 from a THF solution, the adduct (AlMe)8(CCH2Me)5H·2THF (5) was isolated as the first stable ether adduct of a carbaalane. Crystal structure determination revealed a cube of eight aluminium atoms, five faces of which are bridged by C−CH2Me groups. The sixth face is µ2-bridged by a hydrogen atom, and two opposite aluminium atoms of this face are coordinated by one THF ligand each. When the excess of dimethylaluminium hyd…
Molecular and crystal structure of Nα-(9-fluorenyl)-methoxycarbonyl-L-ornithine hydrochloride diethyl ether solvate
2002
The solid-state conformation of the first N-protected ornithine derivative has been established by X-ray analysis. The hydrochloride of Nα-(9-fluorenyl)methoxycarbonyl-l-ornithine crystallises as diethyl ether solvate. The backbone (ω0 ϕ, ψ χ1) torsion angles are (174.9°,–84.0°, 145.9°,–171.0°). The conformation of the urethane amide bonds istrans. The ornithine aliphatic side chain adopts preferred fully extended conformation which is stabilised by the hydrogen bonding of the-NH3+ group to the diethyl ether molecule, carboxyl group and Cl− anions.
Hydrogenolysis of carbon–carbon σ-bonds using water catalysed by semi-rigid diiridium(iii) porphyrins
2019
Semi-rigid diiridium(III) porphyrin alkyls with m-xylyl and p-xylyl diether linkers were synthesized. They were found to be catalysts for the carbon–carbon σ-bond hydrogenolysis of [2.2]paracyclophane under neutral conditions using water as the hydrogen source. The ether linkages in semi-rigid diiridium(III) porphyrins are unstable and undergo cleavage during the reaction.
Hydrogen: a good partner for rhodium-catalyzed hydrosilylation
2014
The influence of hydrogen pressure on the hydrosilylation of ketones catalyzed by [((S)-SYNPHOS)Rh(nbd)]OTf has been studied. We have notably demonstrated that hydrogen significantly affected the outcome of the reaction while not being consumed as stoichiometric reducing agent. In THF, diethyl ether or toluene, the hydrogen pressure exceedingly accelerated the hydrosilylation reaction and preserved or even improved the enantioselectivity of the process. In CH2Cl2, the rhodium catalyst also showed generally higher catalytic activity under hydrogen pressure. Most serendipitously, several ketones were found to give products of absolute opposite configuration upon performing the hydrosilylation…
Polymere ester von säuren des Phosphors, 3. Polymerisation des 2-Äthoxy-2-oxo-1,3,2-dioxaphospholans
1975
2-Athoxy-2-oxo-1,3,2-dioxaphospholan (1) wird durch verschiedene Alkoholate sehr schnell und in hoher Ausbeute zu Poly[oxy(athoxyphosphoryl)oxyathylen] (3) polymerisiert. Die Produkte sind hochviskos und farbols. Sie losen sich in Wasser, Alkoholen, Tetrahydrofuran, Dioxan, Methylenchlorid, Chloroform und Dimethylsulfoxid; unloslich sind sie in Ather und in Kohlenwasserstoffen. Polymerisationsgrade bis 83 (M = 12600) wurden gemessen. In wasriger Losung bei Raumtemperatur erfolgte auch nach Tagen kein merklicher hydrolytischer Abbau. Der mutmaslich anionische Polymerisationsmechanismus und mogliche Nebenreaktionen werden kurz diskutiert. 2-Ethoxy-2-oxo-1,3,2-dioxaphospholane (1) is polymeriz…
Deoxygenative Divergent Synthesis : En Route to Quinic Acid Chirons
2020
The installation of vicinal mesylate and silyl ether groups in a quinic acid derivative generates a system prone for stereoselective borane-catalyzed hydrosilylation through a siloxonium intermediate. The diversification of the reaction conditions allowed the construction of different defunctionalized fragments foreseen as useful synthetic fragments. The selectivity of the hydrosilylation was rationalized on the basis of deuteration experiments and computational studies. peerReviewed
A versatile methodology for the controlled synthesis of photoluminescent high-boron-content dendrimers.
2013
Fluorescent star-shaped mol- ecules and dendrimers with a 1,3,5-tri- phenylbenzene moiety as the core and 3 or 9 carborane derivatives at the pe- riphery, have been prepared in very good yields by following different ap- proaches. One procedure relies on the nucleophilic substitution of Br groups in 1,3,5-tris(4-(3-bromopropoxy)phe- nyl)benzene with the monolithium salts of methyl and phenyl-o-carborane. The second method is the hydrosilylation reactions on the peripheral allyl ether functions of 1,3,5-tris(4-allyloxy-phe- nyl)benzene and 1,3,5-tris(4-(3,4,5-tris- AAA with suitable carboranyl-silanes to produce different generations of dendrimers decorated with carboranyl fragments. This ap…