Han-Yuan Gong

Peripheral benzannulation reorganizes the solid-state packing from isolated bilayers into extended intermolecular π-overlap and enables intense red circularly polarized luminescence at 682 nm with | g _lum | values of up to 1.79 × 10 ⁻² .

BN dative bonds, derived from Lewis acid–base interactions, have emerged as versatile motifs for self‐assembly because they combine directionality, reversibility, and coordination‐induced geometric adaptability. These features support the formation of architectures ranging from macrocycles and cages to interlocked systems, crystalline polymers, and boron–nitrogen organic frameworks. This review surveys the development of BN‐bond‐driven self‐assembly in both discrete and extended systems, with emphasis on how Lewis acidity/basicity, steric effects, linker geometry, secondary interactions, and activation conditions govern structure and function. Representative studies show that B–N self‐assembly enables host–guest recognition, switching, separation, sensing, photocatalysis, and robust porous materials. Persistent challenges, however, include bond lability, competing cyclization and polymerization pathways, framework collapse, interpenetration, and the difficulty of achieving stable three‐dimensional porous architectures. Overall, this review provides a unified perspective on the design principles, functional scope, and future development of B–N‐based self‐assembled materials.

Chiral amplification in host-guest systems remains difficult to control because structures tend to be either too rigid to accommodate a guest or too flexible to maintain stable helicity. This is a limitation where binding of chiral substrates is a key to chiroptical induction and the production of, e.g., a circular dichroism (CD) or circularly polarized luminescence (CPL) response. Here, we introduce a supramolecular-based adaptive-locking chirality (ALC) strategy that integrates chirality induction and helicity control within a molecular organic cage (Cg). This cage is flexible and able to bind a broad range of chiral acids. After the capture of four guests and saturation of the four available binding sites, conformational locking of Cg occurs, which stabilizes a single helical configuration. Structural, spectroscopic, and kinetic analyses reveal a guest-dependent progression from rapid helix interconversion to a structure characterized by fully immobilized chirality. These structural changes were found to correlate directly with the emergence of increasingly strong chiroptical signals. The |g_abs| and |g_lum| values for the resulting complexes were found to reach 0.044 and 0.012. A quantitative correlation between desymmetrization as inferred from NMR spectroscopic analyses (Δν) and the |g_lum| values was observed. This enables a predictive assessment of the chiroptical performance for Cg and may provide a general strategy for evaluating a priori high-performance chiroptical materials.

Helicenes, known for their helical π ‐conjugated structures and pronounced chiroptical properties, hold great promise for optoelectronic and photonic applications. However, simultaneously enhancing their configurational stability, emission efficiency, and chiral luminescence remains a synthetic challenge. Herein, we introduce an indolo[3,2,1‐jk]carbazole (ICz) core incorporation strategy to construct two structurally defined, expanded helicenes: rac‐1 and meso‐1 . This strategy, when synergistically combined with π ‐extension via aromatic fusion, significantly improves molecular rigidity, suppresses non‐radiative decay, and enhances photophysical and chiroptical performance. Structural analysis confirms that both compounds adopt well‐defined helical architectures with high configurational stability. Remarkably, rac‐1 exhibits narrowband red fluorescence (full width at half maximum (FWHM) = 16–20 nm), a high quantum yield ( Φ _F = 0.54), and good circularly polarized luminescence (| g _lum | = 1.17 × 10 ⁻³ ; B _CPL = 66.6 M ⁻¹ cm ⁻¹ ), outperforming previous analogs. Both helicenes also show excellent resistance to protonation, oxidation, and thermal racemization. These results underscore the power of the ICz core incorporation design in stabilizing the helicene framework and unlocking new levels of optical and chiral performance, offering a versatile platform for next‐generation functional chiral materials.

Precise control over interlayer organization in nanographenes is a central challenge in carbon materials science because stacking geometry governs their electronic, supramolecular and chiroptical behaviors. Here we report a topological...

Precise control of covalent bonding in nanographene is crucial for tuning its structure-dependent properties and enabling advanced functional materials. Herein, we report a nitrogen-doped nanographene featuring a C₂-symmetric bilayer framework via incomplete Scholl oxidation. Structural, spectroscopic, and computational analyses reveal distinct optical behavior, environmental responsiveness, and quasi-reversible redox characteristics. The inability to resolve enantiomers highlights rapid chiral inversion. These findings offer valuable insights into designing stimuli-responsive heteroatom-doped nanographenes through covalent bond modulation.

Chiral imidazolium-based bismacrocycles exhibiting aggregation-induced emission (AIE) display an unusual, reversible inversion of circular dichroism (CD) signals upon aggregation in 1,4-dioxane solution. In the solid state, exposure to 1,4-dioxane vapor significantly enhances fluorescence intensity and quantum yield, accompanied by a concomitant reversal in CD helicity. These results demonstrate a rare example of solvent-responsive chiroptical switching in macrocyclic AIE systems, driven by aggregation and vapor-induced structural reorganization.

Neutral organic radicals have attracted interest for their stability and redox activity. We synthesized π-extended triarylmethanol (1-OH) with three HBC units, which undergoes SnCl₂-mediated radical transformation into nanographenes. Protonation with trifluoroacetic acid forms a carbocation (1⁺) that rapidly reverts to 1-OH in air, reflecting the destabilizing effect of π extension. These findings reveal how extended aromatic frameworks influence radical and cation stability, offering guidance for the design of 3D nanographene-based materials.

The aggregation state modification of graphene, including nanographene molecules, is essential for optimizing their performance in various applications. However, the current understanding of how to regulate the structures and features of nanographene aggregates primarily relies on non‐covalent bonding interactions, while achieving exact control remains a significant challenge. Herein, we describe unique occurrence in which a σ‐bond is reversibly constructed and subsequently broken to produce dimeric nanographene and monomeric analogues. These molecules are fused with azulene unit(s) at the edge. The acid‐driven transformation occurs with a radical mechanism. Moreover, the manipulation of the chemical employed to terminate the reaction can regulate the selective creation of dimer and monomer. As compared to the monomer, the dimer with a helical structure exhibited a substantial rise in the molar absorbance coefficient (ɛ), fluorescence emission, a greater range of electrochemical characteristics, and much enhanced chirality stability. This study presents an unprecedented strategy that can precisely control and modulate the structures of aggregation state and characteristics of nanographene by regulating covalent bond cleavage and formation.