Chiral and Achiral Pendant-Bound Poly(biphenylylacetylene)s Bearing Amide and/or Carbamate Groups: One-Handed Helix Formations and Chiral Recognition Abilities
Chiral and Achiral Pendant-Bound Poly(biphenylylacetylene)s Bearing Amide and/or Carbamate Groups: One-Handed Helix Formations and Chiral Recognition Abilities
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DOI：
10.1021/acs.macromol.2c01362
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发表时间：
2022-08-23
期刊：
影响因子：
5.5
通讯作者：
Yashima, Eiji
中科院分区：
文献类型：
--
作者：
Ikai, Tomoyuki;Okuda, Shogo;Yashima, Eiji
通过酰胺（- nhco -）或氨基甲酸酯（- nhcoo -）连接剂，通过相应的双苯基乙炔（BPA）单体聚合，制备了一系列具有手性和非手性基团的顺式聚（联苯乙炔）（PBPA）衍生物，该衍生物可由新型氨基功能化双酚A一步合成。研究了共价和非共价手性相互作用对pbpa中过量单手螺旋的诱导作用及其作为高效液相色谱手性固定相的手性识别能力。含光学纯l -氨基酸残基的pbpa在延伸螺旋和收缩螺旋之间表现出独特的两态螺旋构象变化，这是由溶剂介导的垂链之间或每个垂链上分子内氢键形成的开/关开关所调节的。螺旋型多溴联苯的手性识别能力受悬垂的l -氨基酸残基种类的显著影响。携带l -亮氨酸衍生垂链的优选手性收缩螺旋PBPA对各种外消旋化合物（包括轴性和点性手性化合物以及手性金属配合物）具有良好的手性分辨能力。一些外消旋体的螺旋构象变为延伸螺旋时，其洗脱顺序完全颠倒。另一方面，由其优选手性顺螺旋PBPA衍生的反式富集的非螺旋l -亮氨酸结合PBPA和由非共价手性相互作用和随后的螺旋性静态记忆诱导的非手性悬挂结合的顺螺旋PBPA分别表现出较差的手性识别和无手性识别。
A series of cis-poly(biphenylylacetylene) (PBPA) derivatives bearing chiral and achiral pendant groups at the 4'-position of the biphenyl units through an amide (-NHCO-) or carbamate (-NHCOO-) linker were synthesized by polymerization of the corresponding biphenylylacetylene (BPA) monomers that can be readily prepared in one step from a novel aminofunctionalized BPA. An excess one-handed helix induction in the PBPAs through covalent and noncovalent chiral interactions and their chiral recognition abilities when used as chiral stationary phases for high-performance liquid chromatography were investigated. PBPAs bearing optically pure L-amino acid residues showed unique two-state helical conformational changes between the extended and contracted helices regulated by the solvent-mediated on/off switching of the intramolecular hydrogen-bonding formations between the pendants or at each pendant. The chiral recognition abilities of the helical PBPAs were significantly influenced by the kinds of the pendant L-amino acid residues. The preferred-handed contracted helical PBPA carrying an L-leucine-derived pendant showed an excellent chiral resolving power toward various racemic compounds including axially and point chiral compounds and chiral metal complexes. The elution orders of some racemates were completely reversed when its helical conformation was changed to the extended helix. On the other hand, the trans-enriched nonhelical L-leucine-bound PBPA derived from its preferred-handed cis-helical PBPA and achiral pendant-bound cishelical PBPAs induced by noncovalent chiral interactions and subsequent static memory of the helicity showed a poor and no chiral recognition, respectively.