Design of Helical Poly(<i>N</i>-propargylamides) that Switch the Helix Sense with Thermal Stimuli
作者:Junichi Tabei、Ryoji Nomura、Fumio Sanda、Toshio Masuda
DOI:10.1021/ma030501f
日期:2004.2.1
at certain temperatures, which depended on copolymer composition. The temperature dependence of helix sense of the copolymers allowed the determination of thermodynamic parameters. The helical structure of poly(1-co-2), which has long alkyl pendants, was affected by external stimuli more than poly(1-co-3) was. The thermodynamic parameters of helix inversion were also influenced by solvent polarity.
手性N-炔丙基酰胺,(S)-N-炔丙基-2-甲基癸酰胺(1)和(R)-N-炔丙基-3,7-二甲基辛酰胺(2)或(1S)-N-炔丙基- 3-氧代-2-氧杂- 4,7,7-三甲基-2-双环[2.2.1]庚烷-1-基-乙酰胺(3)与(NBD)进行的Rh + [η 6 -C 6 H ^ 5乙-(C 6 H 5)3 ]催化剂,得到相应的中等分子量的共聚物(Mn = 1.9万至5.6万)。CD光谱研究表明,这两种类型的共聚物具有不同的组成,形成螺旋结构,并经历了温度变化驱动下的螺旋-螺旋转变。在所有情况下,光学活性在某些温度下都为零,这取决于共聚物的组成。共聚物的螺旋感的温度依赖性允许确定热力学参数。具有长烷基侧基的poly(1 - co - 2)的螺旋结构比poly(1 - co - 3)受外部刺激的影响更大。螺旋转化的热力学参数也受溶剂极性的影响。