Roy & Diana Vagelos Laboratories, Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States.
Department of Physics and Astronomy , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6396 , United States.
J Am Chem Soc. 2019 Apr 17;141(15):6162-6166. doi: 10.1021/jacs.9b02206. Epub 2019 Apr 2.
Frank-Kasper phases and liquid quasicrystals self-organize from supramolecular spheres of dendrimers, block copolymers, surfactants and other self-assembling molecules. These spheres are expected to be achiral due to their isotropic shape. Nevertheless, supramolecular spheres from short helical stacks of crown-like dendrimers self-organize a Pm3̅ n cubic (Frank-Kasper A15) phase which exhibits chirality on the macroscopic scale. However, the chirality of classic isotropic supramolecular micellar-like spheres, generated from conical dendrons, is unknown. Here we report a library of second and third generation biphenylpropyl dendrons with chiral groups at their apex that produces single-handed chiral supramolecular spheres. Up to 480 conical dendrons self-assemble to form micellar-like spheres, with a molar mass of up to 1.1 × 10 g/mol, that self-organize into a Pm3̅ n phase with chirality detectable on the macroscopic scale. This demonstration of chirality in micellar-like spheres of a Frank-Kasper phase raises the fundamental question whether micellar-like spheres forming 3D phases generated from other soft matter such as block copolymers, surfactants, and other molecules are chiral.
弗兰克-卡珀相和液体准晶从树枝状大分子、嵌段共聚物、表面活性剂和其他自组装分子的超分子球体中自组织形成。由于它们的各向同性形状，这些球体预计是手性的。然而，由冠形树枝状大分子的短螺旋堆叠自组织形成的超分子球体呈现出立方 Pm3̅ n（弗兰克-卡珀 A15）相，在宏观尺度上表现出手性。然而，由锥形树枝状大分子生成的经典各向同性超分子胶束状球体的手性尚不清楚。在这里，我们报告了一系列具有手性基团的第二代和第三代联苯丙基树枝状大分子，它们产生单手性超分子球体。多达 480 个锥形树枝状大分子自组装形成胶束状球体，摩尔质量高达 1.1×10 g/mol，这些球体自组织成具有宏观尺度上可检测到手性的 Pm3̅ n 相。在弗兰克-卡珀相中胶束状球体的手性证明了一个基本问题，即是否由其他软物质（如嵌段共聚物、表面活性剂和其他分子）形成的 3D 相的胶束状球体是手性的。
