Chinese Journal of Chemistry最新文献

Thermally activated delayed fluorescence (TADF) materials that simultaneously exhibit short-range (SR) and long-range (LR) charge-transfer (CT) excited states represent a promising new class of emitters for organic light-emitting diodes (OLEDs). Such systems combine the advantages of conventional donor–acceptor (D–A) and multi-resonance (MR) emitters, including high photoluminescence quantum yield (PLQY), fast radiative decay (k_r) and reverse intersystem crossing rates (k_RISC), and narrowband emission profiles. However, their molecular design principles and structure–property relationships remain largely unexplored. In this work, two new TADF emitters featuring both SR-CT and LR-CT excited states were developed by attaching electron donors to an MR fragment via a boron–meta–donor linkage. Together with reference compounds, these emitters enable a systematic investigation of the influence of the donor structure and linkage mode on the key photophysical properties of such light-emitting materials. Compared with conventional boron–para–donor linked emitters, the boron–meta–donor linked designs display highly hybridized SR–LR–CT character, manifested in distinctive emission bandwidths, enhanced solvatochromism, and donor-strength-dependent excited-state kinetics. Leveraging these features, high-performance narrowband OLEDs were fabricated, achieving a maximum external quantum efficiency (EQE_max) of 35.1% and exhibiting remarkably low efficiency roll-off, with an EQE of 18.1% maintained at a luminance of 10,000 cd·m⁻².

α-Nitroketones represent an important class of organic compounds in synthetic chemistry because of the synergistic interaction between their adjacent carbonyl and nitro functional groups. However, current reporting methods often pose environmental concerns and require harsh reaction conditions, such as the use of noble metal catalysts and external oxidants. Herein, we report a novel and environmentally benign electrochemical bifunctional groups strategy for the efficient synthesis of α-nitroketones directly from olefins. This approach is based on a dual-source system, in which Fe(NO₃)₃·9H₂O serves as a versatile precursor, simultaneously supplying the nitro group, while trace amounts of water inherently present in the electrolyte act as the oxygen source for carbonyl formation. This tandem oxidation–nitration process enables the direct construction of the valuable α-nitroketone scaffold from simple starting materials in a single operational step. A primary advantage of this methodology lies in its inherently green and sustainable nature. Compared with conventional methods, this strategy markedly decreases the necessity of using hazardous and volatile nitromethane as a nitro source and avoids the routine application of stoichiometric condensation or oxidizing agents that tend to produce large quantities of chemical waste. Instead, electricity functions as a traceless redox agent, driving the transformation under mild conditions—generally at room temperature or with minimal heating and under ambient pressure. This leads to a significantly reduced environmental footprint and enhances operational safety. The reaction demonstrates remarkable synthetic utility, characterized by a broad substrate scope. A wide variety of olefins, including those bearing aryl, aliphatic, and heterocyclic substituents, are smoothly converted into the corresponding α-nitroketones in moderate to good yields. In summary, we have developed a mild, efficient, and sustainable electrochemical route to α-nitroketones. By integrating atom-economic principles with the advantages of electrosynthesis—including inherent safety and scalability—this work provides a powerful and practical alternative to conventional methods, aligning with the growing demands of modern green chemistry.

Organic photovoltaic (OPV) cells hold great promise as next-generation green energy owing to their tunable photoelectronic properties and compatibility with large-area solution printing. However, most high-performance materials have been optimized primarily for standard sunlight, with limited strategies for multi-spectral illuminations. Here, we report two wide-bandgap donor polymers, PDBQx-γ and PDBQx-β, integrating a dibenzo[f,h]quinoxaline unit and a two-dimensional benzodithiophene unit linked by alkyl-thiophene π-spacers. Optimized molecular design of PDBQx-β enables enhanced molecular packing, favorable morphology, and superior charge transport, delivering a power conversion efficiency (PCE) of 13.7% for PDBQx-β:FTCC-Br based on single-junction OPV cells under AM 1.5G illumination. Furthermore, the fabricated large-area OPV modules (23.6 cm²) achieve remarkable PCEs of 26.4% under 660 nm laser, 20.8% under underwater illumination, and 27.3% under indoor light. This study demonstrates a molecular design strategy for wide-bandgap polymers intrinsically compatible with diverse light sources, advancing OPV technology toward multi-scene applications.

Presently, few methods offer broad applicability for optimizing thick-film organic solar cells (OSCs). Here, we identify and implement a functional aid, 4-iodobiphenyl (IBP), in OSCs to optimize active layer morphology and significantly boost device efficiency. In the PM6:A4T-16 system, the optimized volatility of IBP promotes acceptor recrystallization and ordered molecular alignment during thermal annealing, leading to the formation of large aggregates and a fibrous morphology that facilitates efficient charge transport. As a result, the power conversion efficiency (PCE) of IBP-treated devices increases by 20% compared with those using conventional additives such as DIO and DIB. Notably, IBP exhibits broad compatibility, delivering substantial efficiency enhancements in PM6:BTP-eC9 and PM6:D18:L8-BO systems, with the latter reaching a high PCE of 20%. Furthermore, IBP enables thickness-insensitive performance, maintaining a PCE of ~17% at an active layer thickness exceeding 360 nm. These results demonstrate IBP as a highly effective processing aid for multiple donor:acceptor pairs, offering a promising strategy for morphology engineering and advancing the fabrication of high-performance OSCs.

One of the most profound goals of modern organic chemistry is to enrich synthetic method and compound library serving as the foundation of pharmaceutical and material sciences. Meanwhile, the synthesis of structurally complex compounds necessitates tedious multistep procedures. This is certainly not in line with the requirements of green chemistry. Therefore, there is a strong impetus for the development of more concise and sustainable approaches to obtaining such compounds. So far, a number of state-of-the-art strategies for this purpose have been developed. Among them, molecular skeleton editing stands out for its capability of rapidly building or pruning functional molecules. Given the ubiquity of rings in drugs, skeletal editing leading to the generation of biologically privileged cyclic systems is particularly useful. Presented herein is a concise construction of privileged isoindolone fused CF₃-benzooxazocine scaffold based on the cascade reaction of 2-aryl-4H-benzo[d][1,3]oxazine 1 with CF₃-ynone 2. This novel reaction is initiated by aryl C−H alkenylation of 1 with 2 followed by intramolecular aza-Michael addition to form the isoindoline ring, water-promoted oxazine ring-opening and intramolecular oxo-nucleophilic addition to form the oxazocine ring. In forming the isoindoline scaffold, 1 acts as a C3N1 synthon and 2 acts as a C1 synthon. In forming the oxazocine skeleton, 1 acts as another version of C3N1 synthon while 2 acts as a C3 synthon and water acts as an O1 synthon. To our knowledge, this is the first example of one-pot tandem generation of both isoindolone and CF₃-oxazocine scaffold through directing group-assisted C−H bond activation-initiated skeleton editing of easily obtainable substrates. Importantly, some of the products thus obtained showed excellent in vitro anti-Zika virus (ZIKV) activity and moderate to good anti-proliferative activity against three human cancer cell lines.

End group modification is an effective strategy to modulate the energy levels, molecular packing and intermolecular interactions of small molecule acceptors (SMAs) in organic solar cells (OSCs). However, conventional end group linking site in giant molecule acceptors (GMAs) based on SMA subunits often occupies halogen substitution sites of end group, limiting further modification of GMAs and the improvement of their power conversion efficiency (PCE). Here, we developed a serious of GMAs, G-5H6H, G-5F6H and G-5F6F, by shifting the linking site to the 4-position of the 1,1-dicyanomethylene-3-indanone (IC) unit in the SMAs, enabling stepwise halogenation at the 5- and 6-positions. Due to the di-fluorination of inner IC end group, G-5F6F shows enhanced planarity and intramolecular charge transfer effect, resulting in the red-shifted absorption and highly ordered molecular packing. As a result, the OSCs based on D18:G-5F6F achieve the highest PCE of 18.29%. Furthermore, incorporating G-5F6F as the second acceptor into the D18:BTP-eC9 based OSCs has resulted in a remarkable PCE of 19.52% and enhanced device stability. This work demonstrates a synergistic molecular design strategy integrating linking site relocation and fluorination for high-performance OSCs based on GMAs.

The high reactivity and transient nature of non-stabilized sp³-hybridized carbocations have long limited their application in enantiocontrolled transformations. In particular, the difficulty in regulating their lifetime and stereochemical environment has posed a fundamental challenge for asymmetric catalysis. Here, we report a catalytic strategy that addresses these challenges by harnessing cyclopropylcarbinyl cations as reactive yet controllable intermediates. These cations, known for their propensity to undergo rapid rearrangement, are strategically stabilized and directed within a chiral ion-pairing framework. Despite their rarity in asymmetric catalysis, these electrophiles enable highly enantioselective asymmetric Friedel–Crafts alkylation reactions when paired with newly developed phosphoramidimidate catalysts functioning as chiral Brønsted acids. The confined chiral environment provided by these catalysts effectively governs carbocation rearrangement pathways, allowing for precise stereochemical control. This method delivers excellent enantioselectivity and yields across a broad range of arenes, highlighting its generality in arene functionalization. Unlike conventional methods requiring substrate preactivation, our approach directly utilizes alcohol as electrophile precursors, forming water as the sole byproduct through an S_N1-type mechanism. The catalytic system promotes selective desymmetrization of prochiral substrates, converting simple and readily available starting materials into structurally complex chiral products. Importantly, controlled rearrangement of cyclopropylcarbinyl cations plays a key role in expanding molecular diversity without sacrificing enantioselectivity. Overall, this strategy significantly broadens the electrophile scope accessible in asymmetric synthesis. By integrating rearrangement control and chiral Brønsted acid catalysis, the present work establishes a new paradigm for exploiting highly reactive carbocation intermediates. These findings not only advance asymmetric catalysis but also open new avenues for enantiocontrolled transformations involving nonclassical carbocation chemistry.

The catalytic asymmetric synthesis of atropisomers incorporating both axial and central chirality represents an attractive but formidable challenge in synthetic chemistry. We disclose herein a nickel-catalyzed diastereo- and enantioselective silacycloaddition that achieves the atroposelective assembly of multistereogenic aromatic amide-derived atropisomers. This transformation combines dynamic kinetic resolution of racemic aromatic amide atropisomers with asymmetric Si–C bond activation of benzosilacyclobutenes. Employing chiral BINOL-derived phosphoramidite ligand featuring chiral cavity of optimal size, this method provides efficient access to a novel class of phosphorus-containing aromatic amide atropisomers, delivering structurally diverse axially chiral phosphines with concomitant central chirality in good yields, excellent enantioselectivities, and moderate to good diastereoselectivities. This methodology exhibits high configurational stability, as confirmed by both experimental and computational studies, along with remarkable synthetic versatility exemplified by its facile conversion to secondary alcohol-containing atropisomers via desilylation of such organosilicon compounds. Beyond its immediate utility for constructing modular ligand libraries, this work establishes a transformative platform that promises to inspire phosphine substrate-compatible asymmetric transformations, addresses long-standing challenges in the synthesis of stereochemically complex atropisomers, and enables innovative applications across asymmetric catalysis and related fields.