Haba Yasuhiro, Harada Atsushi, Takagishi Toru, Kono Kenji
Department of Applied Materials Science, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan.
J Am Chem Soc. 2004 Oct 13;126(40):12760-1. doi: 10.1021/ja047755g.
The poly(amidoamine) dendrimers having terminal isobutyramide (IBAM) groups were prepared by the reaction of isobutyric acid and the amine-terminated poly(amidoamine) dendrimers with generations (G) of 2 to 5 by using a condensing agent, 1,3-dicyclohexylcarbodiimide. 1H and 13C NMR revealed that an IBAM group was attached to essentially every chain end of the dendrimers. While the IBAM-terminated G2 dendrimer was soluble in water, the IBAM-terminated G3, G4, and G5 dendrimers exhibited the lower critical solution temperatures (LCSTs) at 75, 61, and 43 degrees C, respectively. Because the density of the terminal IBAM groups in the periphery of the dendrimer progressively increases with increasing dendrimer generation, the interaction of the IBAM groups might take place more efficiently, resulting in a remarkable decrease in the LCST. In addition, attachment of IBAM groups to poly(propylenimine) dendrimers could give the temperature-sensitive property, indicating that this is an efficient method to render dendrimers temperature sensitive.
通过使用缩合剂1,3 - 二环己基碳二亚胺，使异丁酸与具有2至5代的胺端基聚（酰胺 - 胺）树枝状大分子反应，制备了具有末端异丁酰胺（IBAM）基团的聚（酰胺 - 胺）树枝状大分子。1H和13C核磁共振显示，IBAM基团基本上连接到树枝状大分子的每个链端。虽然IBAM端基的G2树枝状大分子可溶于水，但IBAM端基的G3、G4和G5树枝状大分子分别在75、61和43摄氏度表现出较低临界溶液温度（LCST）。由于树枝状大分子外围末端IBAM基团的密度随着树枝状大分子代数的增加而逐渐增加，IBAM基团之间的相互作用可能更有效地发生，导致LCST显著降低。此外，将IBAM基团连接到聚（丙烯亚胺）树枝状大分子上可以赋予其温度敏感性，表明这是使树枝状大分子具有温度敏感性的有效方法。
