Chinese Journal of Chemistry最新文献

Dimerization of small-molecule acceptors (SMAs) is an effective strategy to suppress molecular diffusion and enhance the stability of organic solar cells (OSCs), yet many dimerized SMAs (DSMAs) suffer from twisted backbones due to nonplanar SMA units and rotatable σ-bonds, limiting molecular packing and charge transport. Here, two dimerized M-series SMAs, DMS and DMSe, were designed by combining fluorinated central indanone units with thiophene or selenophene π-bridges to modulate backbone planarity and intermolecular packing. The selenophene-linked DMSe exhibits stronger intramolecular noncovalent interactions, resulting in enhanced backbone planarity, tighter π-π stacking, improved charge transport, and favorable phase-separated morphology. When blended with PM6, DMSe-based OSCs achieve a power conversion efficiency of 18.01%, surpassing 17.12% for DMS-based counterparts, while also demonstrating superior thermal and photostability. The improved performance is attributed to higher exciton dissociation, more balanced charge carrier mobilities, and increased face-on molecular orientation. These results highlight the critical role of synergistic π-bridge and central end-group engineering in modulating dimer geometry, optimizing blend morphology, and enhancing device performance and stability.

A series of tetranuclear organotin clusters (Sn-mCl, Sn-opy, Sn-mMe, and Sn-dMe) with different carboxylate ligands (mCl, meta-chloromethylbenzoate; opy, picolinate; mMe, meta-methylbenzoate; dMe, 3,5-dimethylbenzoate) were synthesized and characterized. Evaluations on thermostability and film-forming capability demonstrate the potential of Sn-opy cluster and the mixture of Sn-opy with Sn-mCl cluster additive (m₁/m₂ = 9 : 1, designated as Resist-91) as negative-tone non-chemically amplified resist (n-CAR) materials. The lithographic performances of Resist-91 and Sn-opy resist were evaluated by using electron beam lithography. Sn-opy resist can only resolve the best 22 nm half-pitch (HP) pattern at 2000 μC·cm^–2. Resist-91 exhibits superior lithographic performance and resolves 20 nm HP patterns at 1450 μC·cm^–2, demonstrating a significantly improving of the sensitivity and resolution by the introduction of Sn-mCl. Further extreme ultraviolet lithography demonstrates the capability of Resist-91 to form 20 nm HP patterns at a dose of 39 mJ·cm^–2, with the best Z-factor of 2.1 × 10^–7 mJ·nm³ among ladder-shaped tetranuclear organotin resists. Extensive mechanistic analysis of Resist-91 and model films demonstrates the substitution of Cl atom by pyridine ligand, and the generation of a network consisting of tin oxides and organics with the assistance of Sn-mCl cluster, highlighting the critical role of additives with active ligands.

Open-shell radicals, susceptible to quenching by self-coupling, have found numerous practical applications in materials science and the medical field due to their high reactivity and rich photophysical and electronic properties. Porous and highly customisable crystalline frameworks, such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), are ideal platforms for hosting radicals while suppressing their self-coupled annihilation. Yet, current strategies for introducing persistent radicals into these frameworks involve the benzannulation of sterically bulky alkyne-rich motifs and post-synthetic addition to alkyne moieties, which in turn compromise the porosity and crystallinity of the frameworks. Herein, a simple backfolded alkyne-rich diamine-terminated linker was designed and allowed to form a stable 2D COF, BF-COF. Upon facile thermocyclisation, radical-rich BF-COF-300 was obtained with retained crystallinity and porosity as well as far intense and wider light absorption than the primitive BF-COF. These also feature BF-COF-300 as a better candidate than BF-COF in both photothermal conversion and photocatalytic thioether oxidation.

Photocatalytic semihydrogenation of coal-derived acetylene using water as a hydrogen source under ambient conditions offers a sustainable and petroleum-independent route for ethylene production, yet suffers from the utilization of expensive photosensitizers, weak acetylene adsorption and insufficient generation of active hydrogen (H*). Herein, we fabricate a Co single-atom catalyst anchored on nitrogen-vacancy-rich carbon nitride (Co/C₃N₄-V_N) via in-situ co-polymerization. Owing to enhanced light absorption and charge separation efficiency, the Co/C₃N₄-V_N exhibits a considerably high ethylene production rate of 3916.5 μmol·g_cat⁻¹·h⁻¹ under 420 nm light-emitting diode (LED) illumination without photosensitizers, surpassing bulk C₃N₄ by 53-folds and outperforming previously reported photocatalysts. The photocatalytic experiments, acetylene temperature-programmed desorption analysis, in-situ photo-chemical infrared spectra and theoretical simulations together reveal that N vacancies and Co single atoms in Co/C₃N₄-V_N synergistically promote the acetylene adsorption, H* generation from water dissociation and acetylene hydrogenation, thereby accelerating the kinetics of photocatalytic acetylene semihydrogenation.

Photocatalytic synthesis of hydrogen peroxide (H₂O₂) in systems integrating efficient catalytic reactions, product separation, and in situ collection remains a tremendous challenge. Herein, we report one-pot synthesis of anthraquinone (AQ)-functionalized UiO-66(NH₂) exhibiting exceptional photocatalytic H₂O₂ production rate of 44.8 mmol·g^–1·h^–1 (80.6 times higher than that of UiO-66(NH₂)) under visible light and 191 mmol·g^–1·h^–1 under simulated sunlight, coupled with 96% selectivity for benzyl alcohol (BA) oxidation to value-added benzaldehyde (BzH). The designed photocatalyst can be selectively dispersed in H₂O/BA biphasic interface, enabling spontaneous phase segregation of photogenerated H₂O₂ and BzH for autonomous product separation and continuous collection without external energy. Notably, a remarkable cumulative concentration of 681.6 mM (5452.8 μmol) was attained within 14 h. The results showcase that AQ integration enhances oxygen adsorption and establishes a robust built-in electric field (IEF) between UiO-66(NH₂) and AQ to drive efficient charge separation, facilitating the generation of abundant electrophilic singlet oxygen (¹O₂) via energy transfer (EnT) process. Mechanistic analysis reveals an unconventional H₂O₂ synthesis pathway, in which the generated ¹O₂ is subsequently reduced by electrons to superoxide radicals (•O₂^–), which then couple with protons to yield H₂O₂. This strategy offers a sustainable route for concurrent H₂O₂ and value-added chemical production.

Recently, circularly polarized luminescence (CPL) and room-temperature phosphorescence (RTP) materials have attracted significant attention across various fields. The stereogenic biaryl units are critical sources of CPL and RTP activity, including binaphthyl, binaphthalenediol, and binaphthalenediamine derivatives. However, the stereoselective transformation and chiroptical functionalization of 1,1′-binaphthyl-2,2′-diphemyl phosphine (BINAP) and its oxide (BINAPO) are largely unexplored. Herein, a series of axially chiral luminous molecules is prepared by modular covalent-linking of BINAP/BINAPO and arylamine donors (N-phenylcarbazole (CZ) or triphenylamine (TPA)) at 4,4′-positions to study their photoluminescence and chiroptical properties. Intriguingly, the molecules based on BINAPO emit intense fluorescence, and the persistent RTP of 301−578 ms is achieved when these compounds are doped in the polymer matrixes, which contributes to the formation of the optimized energy gap and intersystem crossing (ISC) by virtue of intramolecular charge transfer (ICT) states and heavier phosphorus atoms. Circular dichroism (CD) spectral studies reveal that all BINAP/ BINAPO derivatives exhibit decent optical activity in dichloromethane (DCM) and weak CPL due to the inferior electro-magnetic transition environment. On the contrary, the co-aggregates, consisting of chiral BINAPO derivatives with helical structures and commercial nematic liquid crystals (N-LCs, 5CB), show significantly enhanced CD and CPL signals with the improved FM value of 0.05−0.10.

Borane catalysis, pioneered by BEt₃, is a powerful method for the ring-opening polymerization (ROP) of epoxides and (co)polymerization of epoxides to generate diverse kinds of polymers. Among these systems, pre-organized dinuclear boranes are highly effective due to cooperative effects. However, current examples are limited to ammonium, phosphonium, and silicon-based structures, restricting the exploration of their structure-performance relationships. Herein, malonate esters were used as precursors to synthesize preorganized dinuclear boron catalysts QC-B1 and QC-B2. These catalysts were combined with tetrabutylammonium carbonate, and the resulting binary systems were investigated for their application in the ROP of propylene oxide (PO). The QC-B1/TBAC exhibited living and controllable characteristics in the ROP of PO and showed good tolerance toward chain transfer agents (CTAs), with one boron center tolerating up to 50 equivalents of CTA. Kinetic studies show the polymerization mechanism depends on the initiator: a mono-initiator leads to intramolecular chain growth, while a dual-initiator favors an intermolecular pathway.

With the growing emphasis on green and sustainable development, the development of low-energy, environmentally friendly intelligent responsive materials has become an important direction. Among these, hydrochromic molecular switches have attracted considerable attention in recent years due to their mild stimulus (water), excellent reversibility, and ease of integration with other systems. These attributes make them particularly suitable for applications such as rewritable paper, smart labels, and environmental sensors. However, most existing molecular switches exhibit only a single visible absorption band, which inherently restricts their chromatic versatility and necessitates multi-dye blending to achieve multicolor outputs. To overcome this limitation, we present a rational molecular design strategy based on asymmetric amino modification of fluoran derivatives. By introducing distinct electron- donating and hydrophilic amino groups at the asymmetric 2- and 6-positions of the xanthene ring, we successfully constructed a series of high-performance hydrochromic molecular switches (M1–M3). Upon exposure to water, these molecules undergo a complete ring-opening isomerization, giving rise to intramolecular dual absorption in the visible region with peak separations exceeding 100 nm. Control experiments and theoretical calculations reveal that the two absorption bands originate from different localized π–π* transitions within the xanthene core, and critically depend on the 2-position amino substituent to activate the higher-energy transition channel. This unique electronic architecture enables precise color-switching behavior, yielding three distinct macroscopic colors: magenta, dark green, and purple-black. These hydrochromic molecular switches, when immobilized on solid substrates, demonstrate excellent reversibility over more than 50 write–erase cycles and maintain high optical contrast. Furthermore, they are fully compatible with water-jet printing, allowing for high-resolution, multicolor patterning on cellulose-based media for rewritable paper applications. This work not only provides a simple and efficient route to multicolor hydrochromism but also establishes asymmetric amino modification as a general principle for engineering intramolecular dual absorption, offering a new perspective for the molecular design and precise color regulation of next-generation stimuli-responsive dyes.

Herein, we report a visible-light-mediated chemo- and regio-selective installation of N and S groups onto alkynes to afford 1,2-disubstituted alkane derivatives through sequential thiol-yne click chemistry and hydroamidation of alkynes with arylthiophenols and sulfonyl azides. This transformation proceeds efficiently under mild conditions with broad substrate scope, accommodating both aromatic and aliphatic alkynes. Central to this approach is the selective activation of the aryl vinyl thioether intermediate with the excited photocatalyst via triplet-triplet energy transfer (EnT) strategy to reach its excited state, which subsequently undergoes hydrogen atom transfer (HAT) with C⁴−H bond of Hantzsch ester (HE) to result in a benzyl radical intermediate and the corresponding HE^• radical. Afterwards, these two radical species could react with sulfonyl azides, respectively, to individually yield the desired product of double hydrofunctionalization of alkynes. The afforded HE^• radical species could involve in the radical chain mechanism to furnish the product according to a combined experimental and computational study. The origins of selectivity for this reaction are also rationalized. This work establishes an alternative photocatalytic approach to tackling the challenges in selectively realizing the difunctionalization of alkynes to access 1,2-diheteroatom-substituted alkanes under mild conditions.