化学
绝对构型
单体
共聚物
构象异构
棉花效应
苯乙炔
手性(物理)
立体化学
烷烃立体化学
圆二色性
苯乙酸
侧链
螺旋(腹足类)
旋光色散
结晶学
聚合物
手征异常
有机化学
物理
分子
晶体结构
生态学
蜗牛
催化作用
Nambu–Jona Lasinio模型
费米子
生物
量子力学
作者
Sandra Arias,Rafael Rodríguez,Emilio Quiñoá,Ricardo Riguera,Félix Freire
摘要
Both the role of the absolute configuration and the tendency of a chiral monomer to promote a certain helical scaffold in a poly(phenylacetylene) (PPA) have been evaluated to study the communication between two chiral monomers within a copolymer chain. Nineteen different PPA copolymer series—47 helical copolymers altogether—were prepared to explore the existence of a chiral-to-chiral communication mechanism. From the data obtained, we found that communication between two different chiral monomers emerges when both exhibit two special features: (a) a different conformational composition—one must exist in a single low-energy conformation (“chiral Sergeant”) and the other must present two conformers (“chiral Soldier”)—and (b) the induction of a similar scaffold in the PPA, either cis–cisoidal or cis–transoidal. In the selected systems, the chiral Soldier includes the 4-ethynylanilide (para position) of either (R)- or (S)-2-methoxy-2-phenylacetic acid pendants characterized by their conformational flexibility (equilibrium between synperiplanar and antiperiplanar conformations). The chiral Sergeant contains the same chiral groups but linked to the backbone in meta position [3-ethynylanilide of (R)- or (S)-2-methoxy-2-phenylacetic acid] and is selected on the basis of its restricted antiperiplanar conformation. Incorporation of a very small amount (1%) of the Sergeant into a chain composed of just the Soldier transforms the originally axially racemic chain into a helix with strong sense preference (either M or P) that is determined by the absolute configuration of the Soldier.
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