نتایج جستجو برای: aza crown ether
تعداد نتایج: 44147 فیلتر نتایج به سال:
A liquid-crystalline benzocrown ether, 4'-[(4''-1,1,2,2-tetrahydroperfluorooctyloxy)biphenyloxycarbonyl]benzo-15-crown-5, was used as a neutral carrier of ion-selective electrodes (ISEs) to elucidate the effect of highly ordered assembling of the neutral carrier on the sensor properties through fluorophilic interactions. The properties for the membrane and the resulting ISEs based on a benzocro...
A series of unprecedented crown ether- and thiacrown ether-derivatized benzene dicarboxylic acid (H2bdc) ligands has been synthesized and incorporated into the prototypical isoreticular metal-organic framework (IRMOF) and UiO-66 materials. In the case of UiO-66, only MOFs comprised from a mixed-ligand composition, requiring both unsubstituted bdc and crown ether containing ligands, could be pre...
This paper describes the acid/base-mediated three-state translational isomerization of two [2]rotaxanes, each containing N-alkylaniline and N,N-dialkylamine centers as binding sites for threaded dibenzo[24]crown-8 units. Under neutral conditions, the dialkylamine unit predominantly recognized the crown ether component through cooperative binding of a proton; when both amino units were protonate...
In the title compound, C(7)H(10)N(+)·ClO(4) (-)·C(12)H(24)O(6), the 4-methyl-anilinium cation inter-acts with an 18-crown-6 mol-ecule forming a rotator-stator-like structure through bifurcated N-H⋯(O,O) hydrogen bonds between the ammonium group of the cation and the O atoms of the crown ether mol-ecule. All three components of the structure possess mirror symmetry. The benzene ring is inclined ...
Recently we reported the profound effects of second-sphere crown ether binding upon the redox energetics and intervalence spectroscopy of selected mixed-valence (Crowd metal complex associatino is driven primarily by ether oxygen/ ammine hydrogen interactions, where the H-bond-donating capability of NH3 is greatly enhanced by coordination to a transition-metal cation.) For delocalized species s...
The title compound, [Na(CF(3)O(3)S)(C(12)H(24)O(6))], features a sodium cation that is coordinated by eight O atoms in an irregular hexa-gonal bipyramidal environment. The equatorial positions are occupied by the six O atoms of an 18-crown-6 ether ring. In the axial positions, there is one O atom of a trifluoro-methane-sulfonate anion and an ether O atom of a symmetry-equivalent crown ether rin...
A series of crown ether complexes of potassium quinolin-8-olates were synthesized and characterized. Catalysis of these complexes towards the ring-opening polymerization of rac-lactide was evaluated. The crown ether complexes of potassium quinolin-8-olate and potassium 2-methylquinolin-8-olate exhibited high catalytic activity and good molecular weight control. The 18-crown-6 complex of potassi...
The reaction of dimethyl-amine, 18-crown-6, and perchloric acid in methanol yields the title compound, C(2)H(8)N(+)·ClO(4) (-)·C(12)H(24)O(6)·H(2)O. The dimethyl-ammonium cation and the water mol-ecule inter-act with the 18-crown-6 unit: N-H⋯O hydrogen bonds are formed between the ammonium NH(2) (+) group and four O atoms of the crown ether, while the water mol-ecule on the other side of 18-cro...
A series of di-, tri-, and tetra-substituted N-tosylaziridines [N-(toluene-p-sulfonyl)aziridines] 1, prepared by aziridination of the corresponding alkenes with N-[(tolyl-p-sulfonyl)imino]phenyliodinane (TsN = IPh), was found to undergo a BF3-catalyzed rearrangement (aza-pinacol rearrangement) under mild conditions to give the corresponding N-tosylimines 2 generally in satisfactory yields.
Supramolecular assembly 1 catalyzes a bimolecular aza-Prins cyclization featuring an unexpected transannular 1,5-hydride transfer. This reaction pathway, which is promoted by constrictive binding within the supramolecular cavity of 1, is kinetically disfavored in the absence of 1, as evidenced by the orthogonal reactivity observed in bulk solution. Mechanistic investigation through kinetic anal...
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