Synthesis of Complementary Double-Stranded Helical Oligomers through Chiral and Achiral Amidinium−Carboxylate Salt Bridges and Chiral Amplification in Their Double-Helix Formation
作者:Hiroshi Ito、Masato Ikeda、Takashi Hasegawa、Yoshio Furusho、Eiji Yashima
DOI:10.1021/ja108514t
日期:2011.3.16
acetylide complex regions, indicating that the chiral substituents on the amidine units biased a helical sense preference. The Cotton effect patterns and intensities were highly dependent on the molecular lengths. The complementary double-helix formation was also explored using the chiral/achiral amidine strands with different sequences in which a chiral amidine unit was introduced at the center (center-chiral)
通过顺序逐步反应合成了一系列从2-mer到5-mer的互补分子链,由带有手性/手性脒或非手性羧基的间三联苯单元通过Pt(II)乙炔配合物连接,并具有手性通过圆二色性(CD)和(1)H NMR光谱研究了双螺旋形成。在 CHCl(3) 中,由 (R)- 或 (S)- 脒单元组成的“全手性”脒链与互补的非手性羧酸链通过脒-羧酸盐桥形成优先手双螺旋,导致Pt(II) 乙炔络合物区域中的特征诱导 CD,表明脒单元上的手性取代基偏向于螺旋有义偏好。棉花效应模式和强度高度依赖于分子长度。还使用具有不同序列的手性/非手性脒链探索互补双螺旋的形成,其中在脒链的中心(中心-手性)或末端(边缘-手性)引入手性脒单元。通过比较CD强度与相应的全手性脒双螺旋的CD强度,研究了手性和非手性脒单元的序列对双螺旋形成中手性放大(“中士和士兵”效应)的影响具有相同的分子长度。全手性和手性/手性脒双链体的变温 CD 实验表明