具有临界构象转变温度的聚苯乙炔热至单向螺旋化及由其控制的手性可转换不对称反应

This project is based on the new finding in our previous study, we found a thermotropic chiral induction system consisting of a chiral amine and a polyacetylene prepared from an achiral phenylacetylene having two hydroxyl groups shows a tunable critical one-handed spiralization temperature (COST) in nonpolar solvents such as toluene and hexane.The conformation of the polyacetylene in the system of polyacetylene/chiral phenylethyl amine/toluene could be induced into one-handed helix along with transformation of main chain conformation from the cis-transoidal to the cis-cisoidal by heating the system to a temperature higher than the COST. The induced CD absorption of the polyacetylene was much stronger than the CD absorption of the polyacetylene prepared by helix-sense-selective polymerization. The COST can be adjusted by changing the chiral amine concentration in the system, and the higher concentration affords the higher COST. This unique thermotropic chiral induction phenomenon may be caused by the difference in strength of H-bonds of -OH/-NH2 and -OH/-OH at different temperature. In addition, the induced one-handed helical clarity of the polyacetylene can be self-stabilized by intramolecular H-bonds after precipitating the polyacetylene in methanol to remove the chiral amine, i.e. the induced one-handed helical chirality of the polyacetylene can be perfectly saved in solid state.In this subject, we will utilize CD, NMR, IR and UV to realize the mechanism of the system and discuss the effect factors, such as temperature, chirality and polarity.This subject aim to develop a new type of polyphenylacetylene having thermotropic helix-inducing ability and it will have the important value on the development in the related fields.

本项目基于申请人近期发现的一种基于聚苯乙炔主链构象转变且具有临界转变温度的均相聚苯乙炔热至单向螺旋化系统。此系统由聚苯乙炔衍生物/手性胺/低极性溶剂组成，低温时系统中聚苯乙炔为顺反式构象且无圆二色吸收，当温度跨过临界温度时，聚苯乙炔圆二色吸收急剧增强，其主链构象亦随之转变为全顺式单向螺旋构象。由于聚合物侧链间分子内氢键作用，高温下所得聚苯乙炔螺旋结构信息可在沉淀分离后以固体材料形式得以完好保存。以上发现在国内外均无类似报道。本项目旨在发展一系列具有热至螺旋化性能和固态手性记忆能力的聚苯乙炔，揭示其热至螺旋化行为作用机制及影响因素。本项目涉及手性化学、高分子化学及超分子化学，对相关领域的交叉发展具有探索意义并为此类新型螺旋聚乙炔的后续应用奠定理论基础。

本项目发现了一种基于聚苯乙炔主链构象转变且具有临界转变温度的均相聚苯乙炔热致单向螺旋化系统。此系统由聚苯乙炔衍生物/手性胺/低极性溶剂组成，低温时系统中聚苯乙炔为顺反式构象且无圆二色吸收，当温度跨过临界温度时，聚苯乙炔圆二色吸收急剧增强，其主链构象亦随之转变为全顺式单向螺旋构象。由于聚合物侧链间分子内氢键作用，高温下所得聚苯乙炔螺旋结构信息可在沉淀分离后以固体材料形式得以完好保存。本课题系统研究了该系统中聚苯乙炔分子的热致螺旋化作用机制、研究了聚苯乙炔分子结构、手性小分子、溶剂、溶液浓度以及系统热历史等对体系中聚苯乙炔热致螺旋化行为的影响。研究了溶液中聚苯乙炔分子热致螺旋化的可逆性及其固态手性记忆效应。本课题执行期间发表SCI论文8篇，获得黑龙江省科学技术奖二等奖1项，在国际学术会议做学术报告2次，在国内学术会议做学术报告2次，申请发明专利1项。本项目实现了系统临界热致螺旋化温度的调控，并得到一系列具有热致螺旋化性能和固态手性记忆能力的聚苯乙炔。本项目涉及手性化学、高分子化学及超分子化学的交叉融合，对相关领域的交叉发展具有探索意义并为此类新型螺旋聚乙炔的后续应用奠定了理论基础。