84993-16-8Relevant articles and documents
New self-assembled archetypes in crown ether substituted Δ ZPhe containing tripeptides
Tomar, Kalpana,Ramanathan, Gurunath
, (2019)
Abstract: We examine the effect of crown ether ring sizes on structure and properties of three terminally protected tripeptides containing substituted dehydrophenylalanine residues; Bz- Δ Phe (12-crown-4)-Phe-Phe-OMe, Bz- Δ Phe (15-crown-5)-Phe-Phe-OMe, Bz- Δ Phe (18-crown-6)-Phe-Phe-OMe. The resultant self-assembly of the peptides generates nano-vesicles, which further alter into the necklace type of structures that were characterized via their SEM, LRTEM, and AFM images. We also report the disruption of these vesicles in the presence of different metal ions. Graphical abstract:: Crown ether conjugated tripeptidesP-12C4 and P-15C5 showed a turn-on fluorescence in the presence of Hg 2 + ions. While the peptides P-12C4 and P-15C5 self-assembled into nanovesicles, P-18C6 self-assembled into a necklace type of structures. Furthermore, incubation of P-12C4 and P-15C5 with Hg 2 + and Na + ions resulted in the fusion of these well-defined nanovesicles.[Figure not available: see fulltext.].
Poly(vinylbenzo macrocyclic polyethers). Synthesis and cation binding properties of 12-crown-4-derivatives
Buchanan, G. W.,Denike, J. K.
, p. 702 - 705 (2007/10/02)
The synthesis of 4'-vinylbenzo-12-crown-4 ether is reported.Polymerization to relatively low molecular weight polymers can be accomplished with a free radical initiator.A copolymer with styrene can be prepared and the Li+, Na+, and K+ binding properties of these polymers are compared to those of their monomeric analogs using salt distribution equilibria in water - methylene chloride.For all cations the homopolymer is found to extract the salts from the aqueous phase most effectively.The copolymer is slightly less effective than the homopolymer but effective than either of the monomers by a factor of approximately 7, indication that cooperative binding is likely.Na+ is the most efficiently extracted cation, followed by K+ and Li+.
Ligands for the Alkali Metals. Part 6. Some Bis(crown) Schiff Bases which form Pocket Complexes with Alkali-metal Cations of Appropriate Size
Handyside, Timothy M.,Lockhart, Joyce C.,McDonnell, Martin B.,Rao, P. V. Subba
, p. 2331 - 2336 (2007/10/02)
Three homologous series of bis(crowns) have been produced by condensation of the appropriate formylbenzocrown with long-chain α, ω-diaminoalkanes.The ligands may be viewed as pocket or crevice sites for alkali-metal cations, lined with donor groups to provide ion-dipole interaction and terminated by a hydrophobic methylene chain.The interaction of these ligands with alkali-metal cations has been investigated by spectroscopic techniques and solvent extraction.Pocket complexes of these bis(crowns) with alkali-metal cations were apparently formed in 'best-fit' situations: thus bis(crown-5) compounds formed pocket complexes with cations larger than sodium, while bis(crown-6) ligands formed pocket complexes with cations larger than potassium.The bis(crown-4) ligands did not appear to complex strongly with any cation.The rates of trapping and release of alkali-metal cations from some of these ligands in methanol solution, investigated by temperature-jump techniques, indicate behaviour distinct from that of any of the crown and cryptand types described in the literature.
