科研之友
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摘要
By reacting mono-substituted or 1,3-bi-substituted [2-(p-formylphenyloxy)ethyloxy]-p-tert-butylcalix[4]arene (3 or 4) with hydrazine hydrate in '1+2' or '2+2' condensation mode, novel benzalazine-bridging biscalix[4]arenes 5 and 7 were conveniently obtained in the yields of 76 and 81%, respectively. Condensation of compound 4 and salicylide hydrazone gave a novel calix[4]arene benzalazine derivative 6 in the yield of 85%. The structures and conformations of all new compounds were characterised by elemental analyses, ESI-MS, 1H NMR and 1H-1H COSY techniques. Biscalix[4]arene 7 adopts a symmetrical cone conformation with tube cavity. The liquid-liquid extraction experiment showed that all new hosts possessed excellent complexation abilities towards soft metal cations. Compound 7 exhibited high complexation selectivity towards Ag+. The Ag+/Na+ and Ag+/Hg2+ extraction percentages of host 7 were as high as 73.1 and 54.9, respectively. The UV-vis spectra complexation experiments revealed that the complexation constant of receptor 7 with Ag+ was 1.9x105M-1 and the 1:1 stoichiometry of receptor 7-Ag+ complex was formed. The 1H NMR spectra complexation experiments suggested that Ag+ was bound in a cavity composed of two benzalazine groups on bridging chains.
- 出版日期2009
- 单位南京大学
