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Calix[4]arenes containing urea and crown/urea moieties: effects of the crown ether unit and Na towards anion binding ability 总被引:1,自引:0,他引:1
Calix[4]arenes containing urea and crown/urea moieties, 7 and 10, respectively have been synthesized. 1H NMR titrations of 7 and 10 with anions in DMSO-d6 showed that 7 and 10 formed complexes with Cl−, Br−, NO3− and H2PO4− to a different extent. The association constants of 7 and 10 towards anions were calculated and found to vary as H2PO4−>Cl−>Br−>NO3−. However, compared to 7 the presence of the crown unit in 10 resulted in a slightly higher affinity to Cl− and Br−, but a lower affinity to H2PO4−. Upon addition of Na+, the binding ability of 10 towards H2PO4− is increased due to ion-pair enhancement. 相似文献
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Nuanphun Chantarasiri Teerawat Damrongkosit Duangruthai Sridaeng 《European Polymer Journal》2004,40(8):1867-1874
Metal-containing polyurethane-ureas and copolyurethane-ureas have been synthesized by the reaction between hexadentate Schiff base metal complexes and isocyanate-terminated prepolymers. The metal complexes employed were MSal2trien, where (M=Ni and Zn, Sal=salicylaldehyde and trien=triethylenetetramine). The NCO-terminated prepolymers used were tolylene 2,4-diisocyanate terminated poly(1,4-butanediol) (PB), tolylene 2,4-diisocyanate terminated poly(propylene glycol) (PP) prepolymers and the prepolymers synthesized from 4,4′-diphenylmethane diisocyanate (MDI) and diols. The diols employed were polycaprolactone diol (PCL) and poly(tetramethylene oxide) (PTMO). Copolyurethane-ureas were synthesized by the reaction between MSal2trien, PB or PP prepolymers and MDI. Characterizations of polymers were carried out using IR spectroscopy, elemental analysis, solubility and viscosity. Flammability of polymers was investigated by measuring limiting oxygen index (LOI) values and thermal stability was studied by thermogravimetric analysis (TGA). 相似文献
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Wilaiporn Chamchaang Nuanphun Chantarasiri Somdej Chaona Chachanat Thebtaranonth Yodhathai Thebtaranonth 《Tetrahedron》1984,40(10):1727-1730
Symmetrical and unsymmetrical stilbenes can be prepared by pyrolysis of the corresponding aryl cinnamates. The mechanism of product formation is discussed. 相似文献
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