| Summary: | 碩士 === 國立臺灣大學 === 化學研究所 === 87 === The ureyleno crown ethers 3, 7, 9 and 12 were designed and synthesized, aiming to study their cooperative complexation with lithium ions. The 7Li NMR experiments of 3, 7 and 9 shows a ligand to metal binding ratio of 0.5. This observation was further confirmed by the 13C NMR study of 3. 13C NMR experiment shows the presence of free ligand 3 and a complex of the ligand 3 with two lithium ions. No peaks corresponding to the complex of ligand 3 with one lithium ion was found. The complexation of the first lithium ion with ligand 3 could preorganize the conformation for the second lithium ion, which is reflected by the higher K2 value (K2>K1).
For compound 9, when the ratio of compound 9 to lithium ion is bigger than 0.5, we can find another peak appears in the 7Li NMR spectrum. This peak is believed to appear from a complex of one lithium ion with two molecules of 9. Besides, we successfully connect the ureyleno crown ether part with calix[4]arene as compound 18.
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