Chinese Journal of Chemistry最新文献

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.

Despite significant progress in catalytic asymmetric (3+X) cycloadditions of bicyclobutanes (BCBs) for constructing pharmaceutically valuable bicyclo[n.1.1]alkanes, current strategies are limited to using a single catalyst for the separate activation of BCBs or the "X" components. Herein, we report a new strategy that synergistically combines achiral Pd-catalysis for BCB activation with chiral iminium activation of α,β-unsaturated aldehydes, thereby overcoming existing limitations. These limitations include issues of chemo-, diastereo-, and enantioselectivity in the (3+2) cycloadditions of BCBs with enals for the synthesis of multisubstituted all-carbon bicyclo[2.1.1]hexanes (BCHs). Despite these challenges, up to 99% ee, >20 : 1 d.r., and 88% yield have been achieved. Moreover, the protocol demonstrates a wide range of substrates, high tolerance to various functional groups, scalable synthesis and versatile product functionalization, highlighting its practical value in constructing complex chiral BCH structures. Additionally, synergizing transition-metal catalysis and organocatalysis activation principles broadens the mechanistic and synthetic scope of the asymmetric cycloadditions of BCBs.

Perovskite solar cells (PSCs) are promising thin-film photovoltaic devices and achieve a high power conversion efficiency (PCE) of 27.3% (certified). Hole transport layer (HTL) composed of nickel oxide (NiO_x) and [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz) is extensively utilized in these devices. However, the dispersion and conductivity of NiO_x are suboptimal, and it exhibits energy-level mismatch. Meanwhile, the coverage of Me-4PACz on NiO_x is non-uniform. Herein, we synthesized magnesium ion-doped nickel oxide (Mg:NiO_x) with more surface hydroxyl groups to address these issues. More surface hydroxyl groups provided more binding sites for Me-4PACz, resulting in a denser and more uniform coverage of Me-4PACz. Consequently, fewer defects were present at the buried interface, and a better environment for the crystallization of perovskite (PVK) was established. Furthermore, Mg:NiO_x/Me-4PACz enabled better energy level alignment with PVK. The Mg:NiO_x-based PSCs achieved a champion PCE of 25.86%, representing a notable improvement over the NiO_x-based devices (24.51%). After 462 h of continuous illumination testing, the PSCs with Mg:NiO_x retained 96.8% of their initial PCE, while those with NiO_x only maintained 62.9% of their initial PCE. Thus, Mg:NiO_x effectively enhanced both the PCE and stability of PSCs.