metal hydroxide was investigate. It was found that the monoarenesulfonates of N,N-di(oligooxyethylene)amines were first formed as intermediates, and their subsequent intramolecular cyclization gave N-unsubstituted monoaza crownethers rather selectively.
Stimuli-Responsive Supramolecular Nanocapsules from Amphiphilic Calixarene Assembly
作者:Myongsoo Lee、Sun-Ja Lee、Li-Hong Jiang
DOI:10.1021/ja045918v
日期:2004.10.1
We synthesized tetrameric amphiphilic molecules based on a calixarene building block that self-assembles into a tunable and stable aggregation structure in aqueous solution. The amphiphilic calixarene molecules with a small hydrophilic part were observed to assemble into a vesicular structure that decreases significantly in diameter with only small increases in the hydrophilic chain length. Further
Different types of water-soluble ligands were synthesized and their capability was evaluated by solvent extraction studies to complex trivalent actinides and suppress their extraction by a strong lipophilic ligand, such as TODGA. The back extraction efficiency of hydrophilic diglycolamide (DGA) derivatives with a varying number of ethylene glycol groups, or containing sodium acetate moieties on the amidic nitrogen shows a decrease in back-extraction efficiency with increasing number of ethylene glycol units on the amidic nitrogen at various pH values of the aqueous phase. Among the PS donating ligands only the ligand with a malonamide backbone exhibits a high reverse extraction efficiency, although, with no selectivity for americium. Within the water-soluble tripodal ligands, i.e. the amide derivatives of nitrilotriacid with N,N-dimethyl and N,N-bis(hydroxyethyl) moieties, the first one shows a pronounced selectivity for Am(III) over Eu(III), with a maximum separation factor of 11.1, while the latter one more efficiently complexes the radionuclides in the aqueous phase with a maximum separation factor of 5. Isothermal microcalorimetry experiments of the complexation of Eu(III) by a selected series of ligands confirm the observed trend in the back extraction properties.
The present invention relates to new class of functionalized macrocycles capable of chelating paramagnetic metal ions, their chelated complexes with metal ions and the use thereof as contrast agents, particularly suitable for Magnetic Resonance Imaging (MRI) analysis.