Ion Extraction and Transport by Proton-Ionizable Crown Ethers

Synthesis and enantioselective transport studies of optically active lipophilic proton-ionizable crown ethers containing a diarylphosphinic acid unit

“…R f : 0. 35 [1,4,7,10,13,16] pentaoxa-k 5 -phosphacyclooctadecin-22-one (R,R)-8. Macrocycle (R,R)-8 was prepared from 5 (0.36 g, 0.91 mmol) and (R,R)-7 2 (0.71 g, 0.91 mmol) in the same way as described above for (S,S)-8.…”

“…The solvent was removed and the crude product was recrystallized from toluene to give 5 (5.68 g, 63%) as a white powder. Mp 120-122°C; [1,4,7,10,13,16] pentaoxa-k 5 -phosphacyclooctadecin-22-one (S,S)-8. Tetraethylene glycol ditosylate (S,S)-7 2 (1.00 g, 1.28 mmol), ethyl phosphinate 5 (0.50 g, 1.28 mmol), and finely powdered anhydrous K 2 CO 3 (2.00 g) were mixed with vigorous stirring in dry DMF (30 mL) under argon.…”

Synthesis and Ionophoric Properties of Crown Ether Capped with a Convergent Hydroxamic Acid Function

“…2 Among these, lariat crown ethers having pH-responsive functions in their arm, such as carboxylic acid and hydroxamic acid derivatives, are particularly attractive for the ionophoric applications. 3 In particular, hydroxamic acid functions are employed frequently in many natural and synthetic ionophore systems and exhibited very unique binding behaviors toward some transition metal ions. [4][5][6][7] Meanwhile, in many of the designed supramolecular systems, obtaining a specific convergent orientation of particular ligating functions toward active site is highly desirable for selective and strong binding of targeted guests.…”