Two‐Dimensional Chiral Polyrotaxane Monolayer with Emergent and Steerable Circularly Polarized Luminescence

Abstract

Here, we propose a mechanically interlocked strategy to achieve a 2D chiral polyrotaxane (2D CPR) monolayer with emergent and steerable CPL activity by utilizing β‐cyclodextrin as the chiral wheel and a luminescent dynamic covalent organic framework as 2D polymeric axle. Such methodology, integrating host–guest and dynamic covalent chemistry, enabled the direct construction of a delaminated 2D CPR monolayer with extraordinarily large size (up to tens of micrometers) and simultaneously endowed chirality to the extended 2D CPR network to generate CPL activity. Importantly, not only the structure but also the CPL performance of the 2D CPR network can be further regulated by the feeding amount of β‐cyclodextrin. This work demonstrated a monolayered 2D CPR with CPL activity for the first time. The insightful structure–property relationship of the induced CPL will be of benefit for a deeper understanding of the excited‐state chirality of 2D chiral nanomaterials.

Circularly polarized luminescence from chiral macrocycles and their supramolecular assemblies

“…Combining the two strategies of mechanical interlocking and dynamic covalent chemistry, our group used β-CD as a chiral wheel and a 2D covalent organic framework as a luminous axis to successfully obtain a 2D chiral polyrotaxane (2D CPR) monolayer with emergent and steerable CPL activity. 113 As shown in Fig. 23, a pyrene diamine and a C 3 -symmetric trialdehyde formed a mechanically interlocked dynamic covalent organic framework through the β-ketoenamine linkage without chirality.…”

Chiral Induction in 2D Borophene Nanoplatelets through Stereoselective Boron–Sulfur Conjugation

“…Chirality is ubiquitous in nature ranging from macroscopic to microscopic systems, with implications for biological and physiological processes. − The concept of chirality has therefore infiltrated numerous areas of research including pharmaceuticals, bioengineering, agriculture and biosensing. − Due to their chiroptical activity and self-assembling capabilities, chiral inorganic nanostructures especially have been a key ingredient in optoelectronics, sensors, and enantioselective catalysis. − These biomimetic nanoparticles display both molecular and nanoscale chirality, corresponding to the geometry of surface ligands and of the nanoparticles as a whole. − By unraveling chirality-dependent interactions on the nano- and molecular scale, these developments have helped us better understand how chirality is selected in biological systems and demonstrated the potential for chiral nanostructures in life science. − Some of the widely used chiral two-dimensional (2D) materials toward this direction are graphene, boron nitride, graphitic carbon nitride, transition metal dichalcogenides, phosphorene, etc. , Borophene, a relatively newer addition to the portfolio of 2D nanomaterial, demonstrates unique chemical and metallic properties with varied structural polymorphism. − The polymorphic nature of borophene, is derived from the bonding configurations among boron atoms, which further distinguishes it from other 2D materials and allows for customization of its material properties. , One of the other interesting facts for this emerging boron allotrope is behind its anisotropic Dirac properties that are hypothesized to largely influence biological interactions. − However, imepdiment in imparting chirality to such materials, the challenge of sustainability, purity of enantiomers, solubility, and stability are growing concerns. Scientists have generally used enantioselective organic–inorganic interactions, template-induced synthetic approaches, and photon-induced methods to introduce chirality in nanomaterials. ,…”

Light-driven self-assembly of spiropyran-functionalized covalent organic framework

“…delivery systems [30][31][32] . Stimuli-responsive self-assembly of one-and twodimensional supramolecular materials, including polyrotaxanes [33][34][35][36][37][38][39][40] , nanotubes 41,42 , nanowires [43][44][45][46][47][48] , and nanosheets 43,[49][50][51][52] , has already been extensively studied 46,47,52,53 . However, the modulation of morphology in response to light has rarely been reported despite being one of the most environmentally friendly sources of external stimuli that is commonly accessible in our daily life 19,20,54,55 .…”