Latest ArticlesIn the exploration of circularly polarized luminescence (CPL) materials, doping cholesteric liquid crystals (CLCs) with achiral dyes is a common strategy. Conjugated polymers are favored as achiral dyes for their superior luminescent properties. In this study, a series of oligomers (M1-M3) and the conjugated polymer F8BT were synthesized to systematically assess the impact of the length of the conjugated backbone on CPL signals of CLCs doped with conjugated polymers. As the length rose from M1 to M3, CPL intensity concurrently increased (glum increased from 0.35 to 0.84), attributable to enhanced dichroism (order parameter, SF increased from 0.20 to 0.56). In contrast, F8BT polymer resulted in diminished CPL intensity (|glum| = 0.64) due to the reduced compatibility. Achieving a balance between dichroism and compatibility is crucial for optimizing CPL in conjugated polymer-doped CLCs. The guiding principle established here may have broad applicability in other CPL assemblies, offering a strategic avenue to engineer high-performance CPL materials with conjugated polymer.
Metal-catalyzed alkene arylalkoxylation is a powerful complexity-building strategy for the synthesis of oxygen heterocycles from simple γ-unsaturated alcohols, but only a few examples of catalytic enantioselective methods exist. Herein, an efficient palladium-catalyzed enantioselective arylalkoxylation of γ-hydroxyalkenes with aryl halides is reported. The salient features of this transformation include a remarkable broad substrate scope, mild reaction conditions, and good functional group tolerance, delivering a series of chiral tetrahydrofurans containing a tertiary or quaternary stereocenter in good yields with up to 95% ee. The Xu10 ligand with a suitable side-arm was responsible for the high reactivity and good enantioselectivity of this transformation.
Highly active transition metal nitrides are desirable for electrocatalytic reactions, but their long-term stability is still unsatisfactory and thus limiting commercial applications. Herein, for the first time, we report a unique and universal room-temperature urea plasma method for controllable synthesis of N-doped carbon coated metal (Fe, Co, Ni, etc.) nitrides arrays electrocatalysts. The preformed metal oxides arrays can be successfully converted into metal nitrides arrays with preserved nanostructures and a thin layer of N-doped carbon (N-C) via one-step urea plasma. Typically, as a representative case, N-C@CoN nanowire arrays are illustrated and corresponding formation mechanism by plasma is proposed. Notably, the designed N-C@CoN catalysts deliver excellent electrocatalytic activity and long-term stability both in oxygen evolution reaction (OER) and urea oxidation reaction (UOR). For OER, a low overpotential (264 mV at 10 mA/cm2) and high stability (>50 h at 20 mA/cm2) are acquired. For UOR, a current density of 100 mA/cm2 is achieved at only 1.39 V and maintain over 100 h. Theoretical calculations reveal that the synergetic coupling effect of CoN and N-C can significantly facilitate the charge-transfer process, optimize adsorbed intermediates binding strength and further greatly decrease the energy barrier. This strategy provides a novel method for fabrication of N-C@ metal nitrides as highly active and stable catalysts.
In 2023, The MOE Key Laboratory of Macromolecular Synthesis and Functionalization in Zhejiang University had achieved several important results in the five research directions. First, for controllable catalytic polymerization, a new silicon-centered organoboron binary catalyst was developed for copolymerization of epoxides, and a series of cooperative organocatalysts were proposed for ring-opening copolymerization of chalcogen-rich monomers. Second, with respect to microstructure and rheology, axially encoded metafiber demonstrated its capacity for integrating multiple electronics, while artificial nacre materials showed improved strength and toughness due to interlayer entanglement. Third, concerning separating functional polymers, interfacial polymerization was monitored via aggregation-induced emission, and vacuum filtration was applied to assist interfacial polymerization. Fourth, in terms of biomedical functional polymers, we designed antibacterial materials such as a novel quaternary ammonium salt that enables polyethylene terephthalate recycling and its antibacterial function, nanozyme-armed phage proved its efficiency in combating bacterial infection, and also transition metal nanoparticles showed capacities in antibacterial treatments. We also made achievements in biomedical materials, including polymeric microneedles for minimally invasive implantation and functionalization of cardiac patches, as well as ROS-responsive/scavenging prodrug/miRNA balloon coating to promote drug delivery efficiency. Besides, methods and mechanisms of RNA labeling has been developed. Fifth, about photo-electro-magnetic functional polymers, through-space conjugation was successfully manipulated by altering subunit packing modes, room-temperature phosphorescent hydrogels were synthesized via polymerization-induced crystallization of dopant molecules, and single crystals of both fullerene and non-fullerene acceptors were grown in crystallized organogel, with their photodetection performance further explored. The related works are reviewed in this paper.
A series of novel crown aldoxime ethers were synthesized, demonstrating notable thermal and hydrolysis stability. The showcased acid-catalyzed and photo-induced cis/trans isomerization, which enables orthogonal control over both guest complexation and the chiroptical effects of these crown aldoxime ethers, manifesting a regulation of complexation through isomerization at binding heteroatoms.
Stimulus-responsive room-temperature phosphorescence (RTP) materials have gained significant attention for their important optoelectronic application prospects. However, the fabrication strategy and underlying mechanism of stimulus-responsive RTP materials remain less explored. Herein, we present a reliable strategy for achieving pH-responsive RTP materials by integrating poly(vinyl alcohol) (PVA) with carboxylic acid or amino group functionalized terpyridine (Tpy) derivatives. The resulting Tpy derivatives-based RTP materials displayed reversible changes in emission color, intensity, and lifetime of both prompt and delayed emission. Notably, the RTP emission undergoes a significant diminish upon exposure to acid due to the protonation of Tpy units. Taking advantage of the decent RTP emission and pH-responsiveness of these RTP films, a spatial-time-resolved anti-counterfeiting application is demonstrated as a proof-of-concept for largely enhancing the security level. This study not only provides new prospects for developing smart RTP materials but also promotes the advancement of optical anti-counterfeiting applications.
Shape-persistent arylene ethynylene molecular cages have been investigated as transmembrane channels for ions and small molecules. The molecular cages were obtained starting from tetrayne monomers through alkyne metathesis cyclooligomerization. We found these porphyrin-based rigid molecular cages can insert into the lipid bilayer and efficiently transport ions and small molecules (e.g., calcein). Our study reveals longer hydrophobic alkyl chains on the cage molecule promote the channeling efficiency, while shorter and/or more polar side chains impair such activity. Kinetic analysis shows linear correlation between the rate of proton transport and the concentration of the cage, suggesting the active species is likely a monomeric cage. We found that C70-encapsulated cages are nearly inactive for transmembrane ion transportation, indicating that ions are likely transported through the internal cavity of the cage. Discrete shape-persistent organic cages represent highly stable synthetic ion channels or pores, which could have interesting applications in biomimetic signaling and drug delivery.
The electrocatalytic reduction of nitrate (NO3–) not only facilitates the environmentally sustainable production of ammonia (NH3) but also purifies water by removing NO3–, thereby transforming waste into valuable resources. The process of converting NO3– to NH3 is complex, involving eight electron transfers and multiple intermediates, making the choice of electrocatalyst critical. In this study, we report a cobalt selenide (CoSe2) nanowire array on carbon cloth (CoSe2/CC) as an effective electrocatalyst for the NO3– to NH3 conversion. In an alkaline medium with 0.1 mol/L NO3–, CoSe2/CC demonstrates exceptional NH3 Faradaic efficiency of 97.6% and a high NH3 yield of 517.7 µmol h–1 cm–2 at –0.6 V versus the reversible hydrogen electrode. Furthermore, insights into the reaction mechanism of CoSe2 in the electrocatalytic NO3– reduction are elucidated through density functional theory calculations.
A photocatalyst-free visible-light-promoted three-component reaction of thianthrenium salts, isothiocyanates, and amines is presented, which affords a rapid and efficient approach to S-arylisothioureas under mild conditions. This developed method exhibits the advantages of readily available raw materials, broad substrate scope, good functional tolerance, and operational simplicity. It is worth mentioning that the byproduct thianthrene can be recycled in quantity, ultimately maximizing the atomic economy of the reaction and avoiding chemical waste. Mechanism investigations support the strategy involving a photoinduced EDA complex.
Benzo[4,5]imidazo[1,2-a]pyrimidine-based derivatives play crucial roles in medicines, pesticides, tracers and photoelectric materials. However, their synthesis approach still needs to be optimized, and their fluorescent properties in intracellular microenvironment are unclear. Here, a Cu(Ⅱ)-catalyzed cascade coupling cyclization reaction was successfully developed to synthesize benzo[4,5]imidazo[1,2-a]pyrimidine scaffold with mild reaction conditions, broad substrate scopes and high yields. After a system study, we found that compound 4aa displayed an optimal viscosity-specific response with remarkable fluorescence enhancement (102-fold) for glycerol at 490 nm. Particularly, 4aa possessed excellent structure-inherent targeting (SIT) capability for lysosome (P = 0.95) with high pH stability and large Stokes shift. Importantly, 4aa was validated for its effectiveness in diagnosing lysosomal storage disorders (LSD) in living cells. The 4aa also showed its potential to map the micro-viscosity and its metabolism process in zebrafish. This work not only affords an efficient protocol to fabricate benzo[4,5]imidazo[1,2-a]pyrimidine derivatives, reveals this skeleton has excellent SIT features for lysosome, but also manifests that 4aa can serve as a practical tool to monitor lysosomal viscosity and diagnose LSD.