Monolithic perovskite/organic tandem solar cells (TSCs) have gained significant attention due to their easy device integration and the potential to surpass the Shockley–Queisser limit of single-junction solar cells. However, the surfaces of wide-bandgap perovskite films are densely populated with defects, leading to severe non-radiative recombination and energy loss. As a consequence, the power conversion efficiency (PCE) of perovskite/organic TSCs lags behind that of other TSC counterparts. To address these issues, we designed a functional ammonium salt, 4-(2-hydroxyethyl)piperazin-1-ium iodide (PZOI), comprising a piperazine iodide and a terminated hydroxyl group, which was applied for post-treating the perovskite surface. Our findings reveal that PZOI reacts with and consumes residual PbX 2 (X: I or Br) to form a 2D perovskite component, thereby eliminating Pb 0 defects, while the terminated hydroxyl group in PZOI can also passivate uncoordinated Pb 2+. Consequently, the shallow/deep-level defect densities of the 2D/3D perovskite film were significantly reduced, leading to an enhanced PCE of single-junction 2D/3D wide-bandgap perovskite solar cells to 18.18% with a reduced energy loss of 40 meV. Importantly, the corresponding perovskite/organic TSCs achieved a remarkable PCE of 24.05% with enhanced operational stability ( T 90 ∼500 h).
An asymmetric isomerization/intramolecular coupling reaction of allylic alcohols to synthesize chiral dihydrocoumarins was successfully accomplished through ruthenium catalysis. This method demonstrates a wide substrate applicability, excellent tolerance for various functional groups, and good enantioselectivities (up to 90% ee). It provides a convenient pathway to produce a diverse range of structurally distinct chiral dihydrocoumarins in good efficiency.
An efficient electrochemical approach has been developed for the construction of 3-sulfanylquinoline derivatives by treating phenylethynylbenzoxazinanones with disulfides in an undivided cell. The protocol provided a convenient route to functionalized quinolines with good functional group tolerance. Moreover, it does not require any metal catalysts or additives, furnishing a series of biological quinolines in moderate to good yields.
Although various routes have been reported for haloazidation, unavoidable problems exist, such as environmentally unfriendly monomer halogen, the need for in situ generation of unstable halogen azides (XN 3), applicability to one type of haloazidation and inability to precisely control selectivity. Herein, we developed a universal strategy for haloazidation of alkenes through controlling the reactivity of IBA-N 3 by switching halogen salts, allowing for the synthesis of a diversity of halogen azide products. Mechanistic studies have shown that by tuning the reactivity of IBA-N 3 via switching halogen salts, different intermediates can be controllably produced to achieve regioselectivity and chemoselectivity in the haloazidation of alkenes.
We present a facile synthetic strategy to create mesoporous Cu 2O nanocrystals with tunable pore structures and surface functional groups of amine derivatives for efficient and preferable electrochemical conversion of CO 2 into ethylene. The structural characteristics of these Cu 2O nanocrystals can be manipulated using a set of amine derivatives, such as pyridine, 4, 4’-bipyridine, and hexamethylenetetramine, during the oxidative etching process of Cu nanocrystals by bubbling gaseous oxygen in N, N-dimethylformamide solution. These amine derivatives not only serve as surface functional groups but also significantly affect the resulting pore structures. The synergistic effect of pore structure confinement and surface amine functionalization leads to the superb Faradaic efficiency (FE) of 51.9% for C 2H 4, respectively, together with the C 2H 4 partial current density of -209.4 mA·cm −2 at -0.8 V vs. reversible hydrogen electrode (RHE). The relatively high selectivity towards C 2H 4 was investigated using DFT simulations, where 4, 4’-bipyridine functionalized Cu 2O seemed to favor the C 2H 4 formation with the low free energy of the intermediates. This study provides a feasible strategy to manipulate the pore structure and surface functionalization of mesoporous Cu 2O nanocrystals by regulating the oxidative etching process, which sheds light on the rational preparation of high-performance CO 2RR electrocatalysts.
An alkyl radical initiated cyclization/tandem reaction of alkyl bromides and alkyl electrophiles by using potassium metabisulphite (K 2S 2O 5) as a connector is developed for the synthesis of various lactam-substituted alkyl sulfones. Notably, this process does not require a metal catalyst or metal powder reductant, highlighting its environmentally friendly features. The reaction demonstrates outstanding substrate adaptability and a high tolerance towards diverse functional groups. Furthermore, the biologically active molecules and commercially available drugs with a late-stage modification are also highly compatible with this transformation. Mechanistic studies revealed that the reaction proceeds through a single-step process involving intramolecular radical cyclization, “SO 2” insertion, and external alkyl incorporation.
By rational modification of electronic and steric properties of pincer ligands, a Co/Fe dual catalyst system is developed for one-pot sequential Markovnikov alkyne hydrosilylation and stereoselective alkene isomerization. The protocol provides an atom-economical and efficient approach to trisubstituted ( E)-alkenyl silanes from widely accessible terminal alkynes with high regio- and stereoselectivities under mild conditions. The utility of this reaction was demonstrated by gram-scale synthesis and derivatization of bioactive molecules. The radical clock and trapping experiments indicated that radical pathway might be operative in the alkene isomerization step.
The aggregation of α-synuclein (α-syn) is strongly influenced by membrane interfaces, but the mechanism of transition from monomers to oligomers at early aggregation stage is not clear. Here, we investigate the adsorption and structure changes of α-syn on oppositely charged aromatic interfaces through in-situ surface-enhanced infrared absorption (SEIRA) spectroscopy and nano-IR technique. The results show that the synergy of electrostatic and hydrophobic interactions leads to a “fast-slow” two-step aggregation pathway on negatively charged interface. Surface adsorption induces the formation of an extended helix structure and subsequently partial helix unwinding in NAC region, which enables the hydrophobic stacking between nearby NAC regions. Stable antiparallel β-sheet rich aggregates are gradually emerging as further interactions of monomers with the fast formed “first layer”. Monomers electrostatically adsorb on positively charged interface by C-terminus with NAC region and N-terminus stretched in solvent, which serve as an aggregation core and induce further adsorption and gradual formation of aggregates with C-terminus exposure. Our results demonstrate the modulation of surface charge and synergy of electrostatic and hydrophobic interactions on the interaction modes and aggregation pathways, which provide insights into dynamic conformation changes of α-syn at early aggregation stage and imply the important role of spatial-temporal heterogeneity of membranes in α-synucleinopathies.
Localized surface plasmon resonance has been demonstrated to provide effective photophysical enhancement mechanisms in plasmonic photocatalysis. However, it remains highly challenging for distinct mechanisms to function in synergy for a collective gain in catalysis due to the lack of spatiotemporal control of their effect. Herein, the anisotropic plasmon resonance nature of Au nanorods was exploited to achieve distinct functionality towards synergistic photocatalysis. Photothermal and photochemical effects were enabled by the longitudinal and transverse plasmon resonance modes, respectively, and were enhanced by partial coating of silica nanoshells and epitaxial growth of a reactor component. Resonant excitation leads to a synergistic gain in photothermal-mediated hot carrier-driven hydrogen evolution catalysis. Our approach provides important design principles for plasmonic photocatalysts in achieving spatiotemporal modulation of distinct photophysical enhancement mechanisms. It also effectively broadens the sunlight response range and increases the efficacy of distinct plasmonic enhancement pathways towards solar energy harvesting and conversion.
Porous organic polymers (POPs) have attracted great attention in past decades. Although diverse functional POPs have been developed, multistimuli-responsive POPs with excellent aggregate-state luminescence together with good chiroptical properties have rarely been reported. Herein, two pairs of Salen-type enantiomeric POPs with multistimuli-responsive luminescence and chiral features were designed and synthesized by facile polycondensation reactions between polyfunctional aggregation-induced emission luminogen (AIEgen)-containing salicylaldehyde derivatives and chiral diamines. With Salen units in polymer backbones as tetradentate ligands, a series of POP-metal complexes were further prepared. The obtained POPs and metal complexes show good porosity, high thermal stability, and obvious circular dichroism signals. Moreover, benefiting from the coexistence of AIEgen and Salen units in polymer structures, these POPs exhibit excellent luminescence performance in aggregate states and tunable fluorescence behaviors in response to external stimuli of Zn 2+ ion, mechanical forces, organic solvent, and acids. Due to the dynamic feature of Schiff base C=N bonds, the present POPs can efficiently undergo hydrolysis reactions under strong acidic conditions to reproduce the AIEgen- containing monomers, and such an acid-induced degradation process can be directly visualized and dynamically monitored via fluorescence variation. These properties collectively make the POPs candidate materials for applications in heterogeneous asymmetric catalysis, fluorescence sensing, biomedicine, etc.
A novel macrocycle based on conformation-adaptive and electron-rich dihydrophenazine was designed and synthesized. On the one hand, the macrocycle showed host-guest interactions with tetracyanoquinodimethane (TCNQ) driving by charge transfer interaction between them. Meanwhile, host-guest complexation was accompanied by fluorescence quenching and conformational change of the macrocycle. On the other hand, the oxidation of the macrocycle resulted in its diradical cation analogue and induced the release of the guest molecule TCNQ, thereby accomplishing reversible binding dynamics. Therefore, this work well illustrates the chemical and structural versatility of dihydrophenazine in the synthesis of macrocycles and their host-guest chemistry.
Ten novel isocoumarins, including four pairs of enantiomers, were isolated from Artemisia dubia var. subdigitata (Asteraceae). Compounds 1, 2 and 3a/ 3b possessed a unique 6/6/6-tricyclic system comprising an unusual 1-(2-methylcyclohexyl) propan-1-one moiety fused with isocoumarin core skeleton. Compounds 4a/ 4b were characterized as an unexpected 2, 5-dimethylcyclohexan-1-one scaffold, and compounds 5a/ 5b and 6a/ 6b were rare 1, 2- seco-isocoumarin. Their structures and absolute configurations were elucidated through spectroscopic data, X-ray crystallography, ECD and NMR calculations with DP4+ analyses. Plausible biosynthetic pathways were proposed from the naturally occurring isocoumarin. Network pharmacological analysis suggested that the targets of compound 1 were significantly enriched in the cell cycle and PI3K-Akt signaling pathway. The molecular docking revealed that compound 1 had high binding affinity with CDK2 (total score: 6.8717). Furthermore, compounds 1 and 2 exhibited inhibitory activity on three human hepatoma cell lines, with inhibitory ratios of 85.1% and 84.5% (HepG2), 88.2% and 87.3% (Huh7), and 69.2% and 69.1% (SK-Hep-1) at 200 µmol·L –1, respectively.
Comprehensive Summary: Organic fluorine compounds are ubiquitous and pivotally important organic molecules, yet their activation and transformation have long been a formidable challenge due to the high energy and low reactivity of C—F bonds. Organic electrosynthesis, an environmentally benign synthetic method in organic chemistry, enables a myriad of chemical transformations without the need for external redox reagents. In recent years, organic electrochemistry has emerged as a powerful tool for achieving the activation and transformation of C—F bonds in fluorine-containing compounds. This review aims to succinctly recapitulate the latest advancements in the electrochemical defluorinative transformations of C—F bonds and to delve into the reaction design, mechanistic insights, and developmental prospects of these methods.
Key Scientists: In 1959, Lund was the first to pioneer the electroreduction of CF3 to CH3 group. Electrochemistry has lately provided new opportunities for efficient conversion of organic fluorides. In 2020, Zhou and coworkers discovered the electrochemical defluorinative carboxylation of α-CF3 alkenes. Lambert and colleagues reported electrophotocatalytic defluorinative amination of aryl fluorides. Electrochemical hydrodefluorination of trifluoromethylketones was developed by Lennox and coworkers in 2021. In the same year, Wang and Guo disclosed electrochemical radical defluorinative alkylation of α-CF3 alkenes with Katritzky salts as the alkyl radical precursors. Subsequently, Wu and Liao described a transition-metal-free, site-selective C—F arylation of polyfluoroarenes with (het)arenes using paired electrophotocatalysis. In 2023, numerous efforts were made to achieve electrochemical C—F bond activation. Xia and Guo developed an organoboron-controlled method for the chemoselective electrochemical sequential (deutero)hydrodefluorination of trifluoroacetamides.