两亲嵌段树枝状分子Gx-PBE-b-Gx-PMPA(OH)x2的合成及多重氢键作用

合成了1~3代的嵌段树枝状分子聚苄醚-聚脂肪酯(Gx-PBE-b-Gx-PMPA, x=1,2,3)和两亲嵌段树枝状分子聚苄醚-周边含羟基的聚脂肪酯[Gx-PBE-b-Gx-PMPA(OH)x2, x=1,2,3]. PMPA(OH)x2-树枝片(Dendron)段周边的羟基数目分别是2, 4和8. 通过1H NMR, 13C NMR, FTIR和基质辅助激光解吸附电离飞行时间质谱(MALDI-TOF)(或场解析电离质谱)技术表征了Gx-PBE-b-Gx-PMPA和Gx-PBE-b-Gx-PMPA(OH)x2的结构. 同时, 采用变温FTIR光谱研究了在两亲嵌段树枝状分子中形成的氢键模式. 结果表明, 随着树枝片代数的增加, 两亲嵌段树枝状分子内趋向于形成作用较弱的分子内氢键, 说明形成3代两亲嵌段树枝状分子的三维结构削弱了羟基形成分子间氢键的能力.

Synthesis of Amphiphilic Block Codendrimers Gx-PBE-b-Gx-PMPA ( OH ) x2 and Study on Temperature Dependence of Multiple Hydrogen Bonds

Block codendrimers Gx-PBE-b-Gx-PMPA were synthesized through a coupling reaction between Gx-PBE dendrons and Gx-PMPA dendrons(x=1, 2, 3). Amphiphlic block codendrimers Gx-PBE-b-Gx-PMPA(OH)x2 were further prepared through removing acetonide protecting groups on the periphery of the Gx-PMPA blocks. Their chemical structures were characterized by 1H NMR and 13C NMR spectroscopies, MALDI-TOF(or FD) mass spectroscopy and FTIR spectroscopy. Meanwhile, FTIR spectrometer equipped with a heating stage was used to study the change of the hydrogen bonds in-between hydroxyl groups with increasing temperature. A widened transition region with increasing dendron generation was found. This result can indicate that with increasing dendron generation the ability of forming intermolecular hydrogen bonds decrease due to the three-dimensional structure of higher generation dendron.