Circularly Polarized Phosphorescence of Benzils Achieved by Chiral Supramolecular Polymerization

Abstract

In current approaches for circularly polarized phosphorescent materials, the crystallization of chiral phosphors suffers from poor processability, while integrating them into an amorphous polymer matrix results in unsatisfactory chiroptical signals due to the absence of chirality communication. Here, we have developed an innovative strategy through chiral supramolecular polymerization of benzil phosphors facilitated by intermolecular hydrogen bonds. The inherent film‐forming capabilities of non‐covalent supramolecular polymers obviate the need for an external polymer matrix. The pronounced helical asymmetry of benzil phosphors resulting from chiral supramolecular polymerization leads to enhanced circularly polarized phosphorescence compared to their non‐hydrogen‐bonded counterparts. The circularly polarized phosphorescent signals can be further modulated by varying the location of stereogenic centers or introducing halogen bonding to benzils. Incorporation of platinum(II) phosphor into the benzil supramolecular polymers induces both chirality and triplet‐to‐triplet energy transfer, leading to a change in circularly polarized phosphorescent color from yellow to red. In summary, chiral supramolecular polymerization of phosphors represents a novel and effective approach to circularly polarized phosphorescent materials.

Chiral Coordination Assembly-Induced Phosphorescent Frameworks for Circularly Polarized Phosphorescence

“…In recent years, some organic materials with CPP activity have been prepared. − Zhang and co-workers incorporated the achiral phosphorescent chromophore dibenzofuran into a chiral cholesterol substrate, enabling the cholesteric liquid crystal to emit CPRTP . An et al reported that axial chiral chromophores, when doped into the polymer chain through free radical cross-linking polymerization, enabled the amorphous copolymers to exhibit CPRTP …”

Stimuli-Triggered Dynamic Transformations in Supramolecular Polymers

“…The noncovalent connection renders inherent responsiveness to supramolecular polymers . For example, the strength of hydrogen bonds varies with solvent and temperature, making them suitable for constructing stimuli-responsive supramolecular polymers that react to changes in solvent polarity and heat. − Particularly, temperature increases can significantly reduce viscosity, facilitating the processing of supramolecular polymeric materials and enabling applications in inkjet printing or coatings for thermosensitive substrates. , In addition to the inherent responsiveness, another intriguing strategy is to incorporate additional stimuli-responsive units into supramolecular polymers. This allows for tailored responses to specific stimuli such as pH values, , chemical additives, , light, − redox, , or mechanical force. − Stimuli-responsiveness can modify the intrinsic properties of monomeric building blocks or influence their noncovalent bonding mode.…”

Synthesis and Properties of Mesogen-Jacketed Liquid Crystal Copolymers with Long-Lived Circularly Polarized Room-Temperature Phosphorescence

“…Attributed to the promising applications in many fields such as 3D display, information encryption, and asymmetric synthesis, − chiral luminescent materials with circularly polarized luminescence (CPL) properties have been widely reported in recent years. Typically, CPL materials consist of chiral and chromophore components that interact in various ways. − To date, many strategies have been developed to prepare high-performance CPL materials with high luminescence quantum yield and a large luminescence asymmetry factor ( g lum ), such as construction of chiral luminescent liquid crystals, , chiral supramolecular assembly, − fluorescence resonance energy transfer (FRET), , and so forth. However, most reported CPL materials mainly focused on the fluorescence, − and the research on circularly polarized phosphorescence (CPP) materials is limited.…”