Hase Yoko, Mitsutsuji Yuuki, Ishikawa Masayoshi, Maeda Katsuhiro, Okoshi Kento, Yashima Eiji
Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan.
Chem Asian J. 2007 Jun 4;2(6):755-63. doi: 10.1002/asia.200700051.
The achiral sodium salt of poly(4-carboxyphenyl isocyanide) (poly-1-Na) folds into a one-handed helix induced by optically active amines in water. The induced helicity remains when the optically active amines are completely removed, and further modification of the side groups to amide residues is possible without loss of memory of macromolecular helicity. Although the helical poly-1-Na loses its chiral memory at high temperature, helical polyisocyanides modified with achiral primary amines, which no longer have any chiral components, keep their memory perfectly even at 100 degrees C in N,N-dimethylformamide in some cases and exhibit cholesteric liquid-crystalline phases, thus providing a robust scaffold with heat resistance to which a variety of functional groups can be introduced.
聚(4-羧基苯基异氰化物)的非手性钠盐(聚-1-Na)在水中被旋光性胺诱导折叠成单手螺旋。当旋光性胺被完全去除时,诱导的螺旋性仍然存在,并且侧基进一步修饰为酰胺残基也是可行的,而不会丧失大分子螺旋性的记忆。尽管螺旋状的聚-1-Na在高温下失去其手性记忆,但用非手性伯胺修饰的螺旋状聚异氰化物(其不再具有任何手性成分)在某些情况下即使在100℃的N,N-二甲基甲酰胺中也能完美地保持其记忆,并呈现胆甾相液晶相,从而提供了一种具有耐热性的坚固支架,可引入各种官能团。