Visible Helicity Induction and Memory in Polyallene toward Circularly Polarized Luminescence, Helicity Discrimination, and Enantiomer Separation

Abstract

Inspired by biological helices (e.g., DNA), artificial helical polymers have attracted intense attention. However, precise synthesis of one-handed helices from achiral materials remains a formidable challenge. Herein, a series of achiral poly(biphenyl allene)s with controlled molar mass and low dispersity were prepared and induced into one-handed helices using chiral amines and alcohols. The induced one-handed helix was simultaneously memorized, even after the chiral inducer was removed. The switchable induction processes were visible to naked eye; the achiral polymers exhibited blue emission (irradiated at 365 nm), whereas the induced one-handed helices exhibited cyan emission with clear circularly polarized luminescence. The induced helices formed stable gels in various solvents with helicity discrimination ability: the same-handed helix gels were self-healing, whereas the gels of opposite-handed helicity were self-sorted. Moreover, the induced helices could separate enantiomers via enantioselective crystallization with high efficiency and switchable enantioselectivity.

Spontaneous and photomechanical twisting of a cyanostilbene-based molecular crystal

“…The three-dimensional (3D) helical structure can be widely found in nature, 8,9 and has been shown to activate some unexpected properties of crystalline materials. For instance, the twisted crystal can exhibit circularly polarized emission 10,11 and act as the rotator to control the photonic polarization. 12 Also, the twisted crystals have higher charge carrier mobility.…”

Dynamic Axial‐to‐Helical Communication Mechanism in Poly[(allenylethynylenephenylene)acetylene]s under External Stimuli

“…Dynamic helical polymers have attracted the attention of the scientific community during the last decades due to their stimuli-responsive properties, [1][2][3][4][5][6] which allow tuning their helical sense [7][8][9] or elongation, [10][11][12][13][14] once they have been prepared, via external stimuli such as temperature, pH, chiral additives, cations, or anions among others. [15][16][17][18][19][20][21][22][23][24] Moreover, helical polymers find applications in other fields such as asymmetric synthesis, [25][26][27] or chiral stationary phases in High Performance Liquid Chromatography (HPLC), [28,29] due to their structure/function relationship.…”

Microemulsion-Based Fabrication of Organic Nanocrystals for Persistent Phosphorescence Bioimaging

“…Therefore, crystal formation is an excellent approach to bring persistent phosphorescent materials into biological application. It is gradually coming into the highlight in the past few years since the first research work of crystallization-induced organic phosphorescent compounds. , However, the large size of these crystals makes them unsuitable for bioapplications; in addition, the water insolubility nature of these organic molecules further renders them impractical for bioimaging. − Up to now, several attempts have been made to overcome this bottleneck mainly including saponin encapsulation, self-assembly methods, − and nanocrystallization based on ultrasonication . However, with the development of persistent phosphorescence and the urgent need for bioapplication, more convenient and efficient methods are still needed for the fabrication of water-soluble organic persistent phosphorescent nanocrystals in a controllable manner since the saponin delivery system forms nanoprecipitation with a wide range of nanoparticle sizes.…”