Chemistry - A European Journal最新文献

Donor-acceptor (D-A) conjugated polymers hold significant potential as high-potential thermoelectric (TE) materials due to their adjustable structures, efficient charge transport ability and tunable doping level. However, achieving a balance between the Seebeck coefficient (S) and electrical conductivity (σ) remains challenging. In this work, we employ thienoisoindigo (TIIG) as the acceptor and dithieno[3,2-b:2',3'-d]pyrrole (DTP) as the donor to construct two novel D-A conjugated polymers for TE application. Through introducing thiophene (T) units as spacers between DTP and TIIG, PTIIG-2T-DTP enhances the planarity of conjugated backbones compared to PTIIG-DTP. Moreover, PTIIG-2T-DTP film shows more compact packing between conjugated backbones, which improves the charge transport. Despite slightly lower doping efficiency, doped PTIIG-2T-DTP exhibits superior carrier mobility and conductivity to PTIIG-DTP. Additionally, PTIIG-2T-DTP shows a higher Seebeck coefficient at same doping concentration. Ultimately, PTIIG-2T-DTP achieves a large power factor of 23.2 µWm^-1 K^-2 with σ of 120 S cm^-1 which is much higher than that of PTIIG-DTP. This work develops an effective polymer backbone engineering strategy for developing high-performance D-A conjugated TE polymers.

The development of high-capacity and selective adsorbents for fluoride (F^-) removal is hindered by its inherent characteristics, including its small ionic radius, high charge density, strong hydration ability, high mobility and solubility, as well as the weak diffusion driving force at low concentrations. In this study, a novel composite adsorbent was prepared by loading UiO-66-NH₂ onto carboxymethylated cellulose beads (UiO-66-NH₂@CMCBs) via an in-situ generation strategy for efficient adsorption and recovery of F^-. The highly porous structure and abundant surface carboxyl groups of CMCBs provide favorable coordination sites, promoting the growth of UiO-66-NH₂. Under environmental conditions (25°C, pH 7.4), UiO-66-NH₂@CMCBs completely remove F^- from aqueous solutions with an initial concentration of 10.0 mg L^-1. Furthermore, UiO-66-NH₂@CMCBs demonstrated excellent column adsorption performance and outstanding reusability, maintaining a removal efficiency exceeding 80% after 5 cycles. These results highlight the potential of UiO-66-NH₂@CMCBs as an efficient and recyclable adsorbent for the practical treatment of fluoride-contaminated water.

Aqueous Zn-I₂ batteries suffer from short cycle life due to zinc (Zn) dendrite growth and polyiodide shuttle-induced corrosion. To address these key challenges, a multifunctional protective film of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIMTFSI) ionic liquid, denoted as IL@Zn, was constructed on the Zn anode surface via a tape-casting method to improve the cycle life of Zn-I₂ batteries. EMIM⁺ cations preferentially adsorb on Zn, creating a water-lean inner Helmholtz plane (IHP) and providing steric hindrance for uniform Zn nucleation, while hydrophobic TFSI^- anions enrich at the surface to build a water-repellent interface that excludes H₂O and suppresses parasitic reactions. Moreover, EMIM⁺ hinders iodine dissolution and forms an EMIM⁺-I₃ ^- dominant phase, mitigating the polyiodide shuttle and the associated Zn corrosion. Consequently, IL@Zn symmetric cells deliver over 350 h of stable cycling at 5.0 mA cm^-2. Zn-I₂ full cells with IL@Zn anodes retain 82% capacity after 2000 cycles at 2 A g^-1 and exhibit higher Coulombic efficiency (CE) after self-discharge than cells with unprotected Zn anodes. This work demonstrates a facile strategy for aqueous Zn-I₂ batteries that effectively addresses the challenges of dendrite formation and the shuttle effect.

Understanding and controlling the reactivity of radical species remains a major challenge in many chemical reactions, with the goal of steering and precisely tuning key processes. Recognized as a simple and efficient method for the preparation of 2D nanomaterials, diazonium electrografting is a prime example of a functionalization technique that still requires deeper mastery to meet the demands of future bottom-up approaches. In this work, supported by multiphysics simulations, we achieve an unprecedented understanding of the grafting mechanism involved in nitrobenzene diazonium electrografting and its impact on the resulting nanofilm composition. It is demonstrated that film growth arises from a competition between aryl and diazenyl radicals, leading to the incorporation of variable amounts of azo-bridged nitrophenyl units. By implementing control strategies using radical scavengers and redox inhibitors, corroborated by simulations, we show that diazenyl radicals are preferentially grafted at the substrate/film interface rather than within the film structure itself. Finally, we demonstrate that selective trapping of aryl radicals over diazenyl radicals enables the formation of azo-enriched films, thus opening the way for precise tuning of film composition and selective radical reactivity.

Recent development in the field of organic luminescent materials has gained tremendous attention, particularly due to the materials which exhibit efficient room temperature phosphorescence (RTP). The extensive research in the field has led to variety of metal-free pure organic systems exhibiting excellent performance such as high quantum yield, longer lifetime, and afterglow at ambient conditions. A wide range of strategies were developed to enhance the RTP efficiency, among which the incorporation of chalcogen atoms such as O, S, Se, and Te at bridging position in pure organic system has emerged as a promising strategy. The bridging of the chalcogens atoms not only facilitates the strong spin orbit coupling (SOC) and efficient intersystem crossing (ISC), but also provide more rigid molecular framework to reduce the nonradiative decay pathways and stabilizes the triplet excitons, resulting in RTP with higher quantum yield and longer lifetime. This review focuses on the development of bridged chalcogen-containing pure organic RTP materials with various strategies to achieve more efficient RTP and their applications. In particular, we discuss and compare a broad range of chalcogen containing organic phosphors, highlighting their structural differences and design strategies that affect the phosphorescence under ambient condition.

Organic semiconductor electrocatalysts (OSEs), which integrate the properties of organic semiconductors with electrocatalytic performance, have emerged as promising alternatives to traditional noble metal catalysts due to their low cost, earth abundance, and design flexibility. This article reviews the unique structural features of organic material systems, including small organic molecules, conjugated polymers, covalent organic frameworks (COFs), and organic hybrid materials. It elucidates the structure-activity relationship between the features of organic catalysts and their catalytic advantages. It discusses design strategies, including molecular engineering and interface regulation. Also, it explores applications in key reactions, including the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO₂RR), and nitrogen reduction reaction (NRR). Despite challenges in stability and large-scale preparation, OSEs show great potential in sustainable energy conversion, offering insights for advancing clean energy technologies.

Spin qubits are among the most promising candidates for quantum information processing and sensing technologies. Their potential to function even at elevated temperatures makes them particularly attractive for future devices. However, while extensive studies have been carried out on S = 1/2 systems, high-spin complexes remain much less explored as spin qubit platforms. In this study, we prepared a Zn(II)-based MOF, [CH₆N₃][Zn(HCOO)₃], doped with trace amounts of Mn(II) ions (S = 5/2, 0.2, and 0.02 mol%). Magnetic measurements under static fields revealed slow relaxation phenomena dominated by direct and Raman-like processes. Importantly, Q-band pulsed ESR confirmed quantum coherence between M_S = ±1/2 sublevels, achieving phase memory times (T₂) up to 5.4 µs at 10 K, which is significantly longer than those reported in other Mn(II)-based systems. Rabi nutation experiments verified coherent spin control and multilevel transitions, while Wigner matrix analysis revealed reorientation of the nuclear quantization axis during spin flips. Notably, coherence persisted above 150 K, attributed to the stabilization provided in the MOF's hydrogen-bonded lattice. This work represents the first demonstration of high-spin Mn(II) qubits with measurable coherence at elevated temperatures, underscoring MOFs as versatile and tunable platforms for advancing quantum materials and molecular spin-based technologies.

γ-Butenolides are widespread structural motifs found in many natural and unnatural products which display an impressive range of biological activities. Among them, ε-keto-γ-butenolides represent underestimated butenolide frameworks, which could serve as valuable platforms to build complex structures, for example, heterobicyclic derivatives. Quite unexpectedly, despite the apparent simplicity of their structures, efficient synthetic methodologies enabling the construction of chiral, ε-keto-γ-butenolide architectures are quite underdeveloped. In this context, herein we present a novel, photoinduced regio- and chemoselective γ-alkylation of 2-silyloxyfurans with 2-bromoketones providing a practical access to ε-ketobutenolide scaffolds in racemic format, in one single step and high yields. The usefulness of these products as starting materials to build chiral, fused-heterobicycle lactone derivatives was demonstrated by the implementation of a two-step strategy which successfully delivered unprecedented phenyltetrahydrofuro[3,2-b]furan-2(3H)-one and tetrahydrofuro[3,2-c]pyridazin-6(1H)-one chemotypes.

Fluorocycloparaphenylenes (F-CPPs) are strained, cyclic, π-conjugated molecules with unique electronic and supramolecular properties. Here, we report a novel synthetic approach to create F-CPPs via the formation of macrocyclic palladium complexes that contain covalent Pd-C bonds. The thermal stability of the fluorinated biaryl Pd motifs and the reversibility of the formation of Pd-C bonds enable the self-assembly of macrocyclic Pd complexes. Subsequent ligand exchange with Xantphos facilitates reductive elimination, yielding various F-CPPs that incorporate tetrafluorophenylene, phenylene, or thienylene units. A structural analysis revealed that the thienylene-based F-CPPs adopt tubular packing structures due to their high fluorine content. Optical measurements and time-dependent density-functional-theory (TD-DFT) calculations demonstrated size- and structure-dependent absorption and emission behavior. This Pd-mediated synthetic strategy provides a new platform for the synthesis of functionalized CPPs with tailored properties for potential applications in nanomaterials and supramolecular chemistry.

The Scholl reaction has long stood as a powerful tool for forging C-C bonds in polycyclic aromatic hydrocarbons (PAHs) yet controlling regioselectivity and accessing new reactivity remains a formidable challenge. Here, we unveil a strategically designed platform that exploits electronic tuning within tetraarylthiophenes (TATs) to achieve highly selective [c]-face oxidative cyclodehydrogenation, delivering phenanthro[9,10-c]thiophenes in exceptional yields, a pathway previously inaccessible. Beyond annulation, we uncover a novel oxidative ring-opening reaction, wherein these phenanthrothiophenes undergo selective C─S bond cleavage to yield 9,10-diaroylphenanthrenes-a transformation unprecedented in thiophene chemistry under Scholl-type reaction. Remarkably, we integrate both steps into a one-pot cascade protocol, streamlining direct synthesis from TATs to complex diketone architectures in notable yields. Mechanistic studies, including radical trapping and EPR spectroscopy, point out toward radical (cation/anion) pathways governing these transformations. This dual reactivity-from ring construction to ring cleavage-spotlights new horizons in Scholl chemistry, expanding synthetic access to diverse PAH frameworks and edition of functional edges, that may have potential applications as functional materials in organic electronics.