Inversion of Supramolecular Helicity in Oligo‐p‐phenylene‐Based Supramolecular Polymers: Influence of Molecular Atropisomerism

Abstract

The helical organization of oligo‐p‐phenylene‐based organogelators has been investigated by atomic force microscopy, circular and vibrational circular dichroism, and Raman techniques. Whilst OPPs with more than two phenyl rings in the core self‐assemble into left‐handed helices, that with a biphenyl core shows an inversion of the supramolecular helicity depending on the formation conditions through the atropisomerism of the biphenyl central unit. The results presented herein outline a new example of kinetically controlled modulation of supramolecular helicity.

Chiroptical Studies on Supramolecular Chirality of Molecular Aggregates

“…They applied time‐dependent VCD, VT‐CD, and ROA methods. The sign of VCD couplet single assigned to the amide I groups inverted after 24 h . The observed change reflected the helical inversion of a p‐phenylene chain.…”

“…A number of chiroptical methods such as electronic circular dichroism (ECD), vibrational circular dichroism (VCD), and Raman optical activity (ROA) have been applied to reveal the static and dynamic features of chiral molecules . Among the methods, the VCD spectrum is an extension into the infrared and near‐infrared regions of the circular dichroism spectrum . A main advantage of the method has been its utility in determining the absolute configuration of a chiral molecule in a solution.…”

“…For example, Weiss et al recently reported a work aiming at the development of new molecules with perfluoroalkanamides to gelate fluorous liquids . In the following, the structures and properties of gels as studied by the chiroptical method are reviewed …”

Dynamic control and functionalization of supramolecular chirality

“…如图S2所示, 在Ag + 与 吡啶间配位相互作用存在的条件下, 通过改变水溶 液中分子的浓度实现了组装体在手性螺旋管和二聚 大环结构之间的可逆转变. Sánchez课题组 [40] 对齐聚 图 6 (网络版彩色)加热/冷却和超声调控的超分子手性示意图 [35] Figure 6 (Color online) Schematic illustration of the supramolecular chirality regulated by the heat-cool and sonication method [35] [44] , 并通过控制CdS 的成核与生长位点成功得到了CdS单螺旋与双螺旋 纳米结构 [45] . 刘鸣华课题组 [46] 成为液晶领域的热点之一 [53] .…”

[2 + 2] Photocycloaddition Reaction Regulated the Stability and Morphology of Hydrogels

“…In the past few decades, intelligent responsive materials have become a research hotspot in the field of material science. Supramolecular gels are excellent candidates for smart responsive materials because they can respond to a range of external stimuli, including temperature [1], light [2,3], PH [4], chemical stimulus [5,6], mechanical stress [7], enzymes [8,9], etc. Among all these responsive supramolecular gels, photoresponsive supramolecular gels have the advantages of low price, fast response speed, and spatial selectivity [10].…”