the use of 12 crown 4 extraction of alkali metal
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Answer:
Explanation:
The attachment of 12-crown-4 to the amino group of Pittsburg Compound B (PiB) generated in a simple two-step process to generate a conjugate PiB-C (1), which was shown to change the zeta potential of Aβ fibrils (14CC15792). The synthesis of a bis(benzo-21-crown-7)-based “wheel” was prepared and then threaded with an anthracene-capped dialkyl salt-based “axle,” which is then capped with phenyl isocyanate to lock and generate [3]rotaxanes, which were then photolyzed to produce a poly[3]rotaxane via the reversible photocyclodimerization of the terminal 9-anthryl moieties (14CC14105). An alternative synthesis was described of a 1,1-stable “pseudosuitane”-type complex possessing terminal alkyne moieties, which can undergo a Click reaction with a bisdiazide to create a new sequence of tunable supramolecular polymers (14CC7611). A series of blue supramolecular polymers, based on dibenzo-24-crown-8 functionalized with fluorene-dibenzothiophene-S,S-dioxide co-oligomer along with dibenzyl-ammonium-functionalized fluorine-based oligomers with different counterions, has also been reported (14CC8227). An alternate process to metallosupramolecular polymers possessing dibenzo-24-crown-8 arms has been assembled by coordinating Zn(II) with bis-terpyridine; the crown ether centers were shown to recognize dialkylammonium centers (14CC10841).
Four types of novel C1-symmetric chiral crown ethers, including 28-crown-8, 20-crown-6, 17-crown-5, and 14-crown-3, from maleopimaric acid have been prepared and evaluated for the enantio-discriminating properties with protonated amines (14T9545). Although inherently chiral calix[4]arenes have been known for some time, 2 with its planar chirality has been resolved into its enantiomers whose absolute configuration has been determined (14TA547). Gibson et al. have reported a high (93%) yield regiospecific synthesis of cis(4,4′)-di(carbo-methoxybenzo)-30-crown-10 and its reduction (94%) and macrocyclization in 44% conversion (14JOC9094). Five dioxynaphthalene[38]-crown-10 macrocycles possessing one, two, three, or four allyl moieties have been synthesized; their ability to self-assemble with methyl viologen forming [2]pseudorotaxanes has been reported (14CEJ999). The 15-crown-5 ether mono- and bis(styryl) derivatives of 2,2′-bipyridine have been reported and shown to be potential scaffolds to construct photoresponsive complexes possessing potential metallodendrimer characteristics (14DT769).
