Stable Crystalline Nanohoop Radical and Its Self-Association Promoted by van der Waals Interactions

A stable nanohoop radical (OR3) combining the structures of cycloparaphenylene and an olympicenyl radical is synthesized and isolated in the crystalline state. X-ray crystallographic analysis reveals that OR3 forms a unique head-to-tail dimer that further aggregates into a one-dimensional chain in the solid state. Variable-temperature NMR and concentration-dependent absorption measurements indicate that the π-dimer is not formed in solution. An energy decomposition analysis indicates that van der Waals interactions are the driving force for the self-association process, in contrast with other olympicenyl derivatives that favor π-dimerization. The physical properties in solution phase have been studied, and the stable cationic species obtained by one-electron chemical oxidation. This study offers a new molecular design to modulate the self-association of organic radicals for overcoming the spin-Peierls transition, and to prepare novel nanohoop compounds with spin-related properties.     

A Highly Stable Organic Luminescent Diradical

It is very challenging to obtain stable room-temperature luminescent open-shell singlet diradicals. Herein we report the first stable Müller's hydrocarbon TTM-PhTTM with luminescent properties. Variable-temperature electron paramagnetic resonance spectroscopy measurements and theoretical calculations show that TTM-PhTTM has an open-shell singlet ground state with a diradical character of 90 %. Because of a small singlet-triplet energy gap, the open-shell singlet ground state can be thermally excited to a triplet state. TTM-PhTTM shows room-temperature deep-red emission in various solutions. Unusually high stability of TTM-PhTTM was also observed owing to effective steric hindrance and spin delocalization. Our results are beneficial to the rational design and discovery of more stable luminescent diradical materials.     

Long-range ordering of composites for organic electronics: TIPS-pentacene single crystals with incorporated nano-fibers

Fluorescent nanofibers are incorporated into high-mobility single-crystals without substantially disrupting crystalline lattice, demonstrating a strategy to multifunctionalize semiconducting single-crystals.     

Highly Stable Photo-Assisted Zinc-Ion Batteries via Regulated Photo-Induced Proton Transfer

Photo-assisted ion batteries utilize light to boost capacity but face cycling instability due to complex charge/ion transfer under illumination. This study identified photo-induced proton transfer (photo-induced PT) as a significant process in photo-(dis)charging of widely-used V₂O₅-based zinc-ion batteries, contributing to enhanced capacity under illumination but jeopardizing photo-stability. Photo-induced PT occurs at 100 ps after photo-excitation, inducing rapid proton extraction into V₂O₅ photoelectrode. This process creates a proton-deficient microenvironment on surface, leading to repetitive cathode dissolution and anode corrosion in each cycle. Enabling the intercalated protons from photo-induced PT to be reversibly employed in charge-discharge processes via the anode-alloying strategy achieves high photo-stability for the battery. Consequently, a ~54 % capacity enhancement was achieved in a V₂O₅-based zinc-ion battery under illumination, with ~90 % capacity retention after 4000 cycles. This extends the photo-stability record by 10 times. This study offers promising advancements in energy storage by addressing instability issues in photo-assisted ion batteries.     

Platforms for Stable Carbon‐Centered Radicals

Organic radicals can potentially play important roles in functional materials owing to an unpaired electron, but they are usually highly reactive and difficult to use. Therefore, stabilization of organic radicals is important. Among organic radicals, carbon‐centered radicals are promising because of their trivalent nature, which enables structural diversity and elaborate designs, but they are also less stable because of the reactivities towards carbon–carbon bond formation and atmospheric oxygen. Recently, stable carbon‐centered radicals across diverse molecular platforms have been increasingly explored. This Minireview highlights these newly explored, stable carbon‐centered radicals, with a focus on porphyrinoid‐stabilized radicals because of their remarkable spin delocalization abilities.     

基于曙红Y氧化性猝灭的高活性和高稳定的可见光催化产氢催化剂

以曙红Y(EY)敏化Pt/TiO₂(EY-Pt/TiO₂)光催化产氢体系为模型, 研究了电子传递剂甲基紫精(MV²⁺)的加入对该体系产氢活性和稳定性的影响, 并通过紫外-可见光(UV-Vis)吸收光谱、荧光光谱和光电化学表征手段对MV²⁺的作用机制进行了研究. 结果表明, 当以三乙醇胺(TEOA)为电子给体时, MV²⁺可使EY激发态发生氧化性和还原性淬灭, 有效降低了不稳定中间体EY^3-·的形成和积累, 促进了电子由染料分子向产氢活性位点的有效传递, 从而提高了产氢体系的活性和稳定性. 两种敏化体系瞬态光电流以及产氢活性受EY浓度影响的差异进一步证明, MV²⁺作为电子传递剂有效提高了光生电子的传递和利用效率.     

Post‐Synthesis Treatment gives Highly Stable Siliceous Zeolites through the Isomorphous Substitution of Silicon for Germanium in Germanosilicates

Germanosilicates, an important family of zeolites with increasing number of members and attractive porosities, but containing a large quantity of unstable Ge atoms in the framework, meet with great obstacles in terms of limited thermal and hydrothermal stability when it comes to practical use. A facile stabilization method thus has been developed to substitute isomorphously Ge atoms for Si atoms, giving rise to ultrastable siliceous analogues of the pristine germanosilicates.     

CO2重整甲烷反应高效稳定Ni/ZrO2催化剂的纳米结构特点

分别通过在常压流动N2气中加热处理ZrO(OH)2醇凝胶和在空气中焙烧ZrO(OH)2水凝胶制备了含不同晶相组成和不同尺寸ZrO2纳米粒子的Ni/ZrO2催化剂.Ni/ZrO2催化剂上CO2重整CH4反应的活性和稳定性以及多种催化剂表征(XRD,TEM,TPR及TPD等)数据表明,高效稳定的Ni/ZrO2催化剂必须具有“金属/氧化物”纳米复合物的特征.ZrO2纳米粒子的晶相组成对CO2重整甲烷反应中纳米复合物型Ni/ZrO2催化剂的稳定性没有明显影响.     

Regioselective cyclization of 2-alkynylbenzoic acid in water for the synthesis of isocoumarin

In this work, a regioselective synthesis of isocoumarins from 2-alkynylbenzoic acid is reported. The transformations proceed smoothly with good yields in water via a metal-free radical pathway. When catalytic TBAB is employed, the reaction provides various isocoumarin derivatives according to the structures of the corresponding precursors. It is believed that TBAB serves as a phase transfer catalyst and radical initiator in the reaction. Compared to previous methodologies, the synthetic procedure reported herein provides a more environmentally benign route for the synthesis of isocoumarins.     

Bio-Inspired Polyanionic Electrolytes for Highly Stable Zinc-Ion Batteries

For zinc-ion batteries (ZIBs), the non-uniform Zn plating/stripping results in a high polarization and low Coulombic efficiency (CE), hindering the large-scale application of ZIBs. Here, inspired by biomass seaweed plants, an anionic polyelectrolyte alginate acid (SA) was used to initiate the in situ formation of the high-performance solid electrolyte interphase (SEI) layer on the Zn anode. Attribute to the anionic groups of −COO⁻, the affinity of Zn²⁺ ions to alginate acid induces a well-aligned accelerating channel for uniform plating. This SEI regulates the desolvation structure of Zn²⁺ and facilitates the formation of compact Zn (002) crystal planes. Even under high depth of discharge conditions (DOD), the SA-coated Zn anode still maintains a stable Zn stripping/plating behavior with a low potential difference (0.114 V). According to the classical nucleation theory, the nucleation energy for SA-coated Zn is 97 % less than that of bare Zn, resulting in a faster nucleation rate. The Zn||Cu cell assembled with the SA-coated electrode exhibits an outstanding average CE of 99.8 % over 1,400 cycles. The design is successfully demonstrated in pouch cells, where the SA-coated Zn exhibits capacity retention of 96.9 % compared to 59.1 % for bare Zn anode, even under the high cathode mass loading (>10 mg/cm²).     

Stable Near-infrared-emitting Radical Nanoparticles for Fluorescence Imaging

Stable neutral luminescent radicals with unpaired electrons exhibit unique spin-allowed doublet-doublet transitions, which has attracted significant attention. Although they are pure organic molecules without metal ions thus thought to have low biological toxicity, the application of luminescent radicals to bioimaging has rarely been reported. Here, a stable radical with efficient near-infrared(NIR) emission and good photostability was designed and synthesized. After being wrapped into nanoparticles, it was applied to cell fluorescence imaging. The cytotoxicity experiments suggested that the nanoparticles have remarkable biocompatibility and excellent stability. An NIR fluorescent signal was successfully observed in the cytoplasm of HCT116 cells. The experimental results gave the first example of NIR emitting radical nanoparticles for cell fluorescence imaging and proved the feasibility of the application of luminescent radicals to fluorescence imaging.     

A Water‐Stable Uranyl Organic Framework as a Highly Selective and Sensitive Bifunctional Luminescent Probe for Fe3+ and Tetracycline Hydrochloride

A new coordination polymer (H₂bpy)_0.5?[(UO₂)_1.5(ipa)₂(H₂O)] ( 1 ) (H₂ipa=isophthalic acid, bpy=4,4′‐bipyridine) was synthesized by hydrothermal condition. It was characterized by IR spectroscopy, elemental analysis, TG‐DTA analysis, and powder X‐ray diffraction. Analysis of single‐crystal X‐ray diffraction results showed that the title compound exhibited a double chain bridged by the different uranyl ions and ipa^2? ligands. Through the hydrogen bond interactions and π???π stacking interactions, the double chains were assembled into the three‐dimensional supramolecular framework. Furthermore, the compound can be used as a promising bifunctional luminescence sensor for detecting and identifying Fe³⁺ and tetracycline hydrochloride antibiotic molecules with high selectivity and sensitivity in aqueous solutions. Moreover, the luminescent sensing mechanisms for different analytes were proposed. Moreover, the electronic properties of title compound were explored by density functional theory (DFT) calculations. The sensor system has been successfully applied for the detection of Fe³⁺ and tetracycline hydrochloride with high recovery percentages and low relative standard deviation in real river water samples.     

Polymers Based on Stable Phenoxyl Radicals for the Use in Organic Radical Batteries

Polymers with pendant phenoxyl radicals are synthesized and the electrochemical properties are investigated in detail. The monomers are polymerized using ring‐opening metathesis polymerization (ROMP) or free‐radical polymerization methods. The monomers and polymers, respectively, are oxidized to the radical either before or after the polymerization. These phenoxyl radicals containing polymers reveal a reversible redox behavior at a potential of −0.6 V (vs Ag/AgCl). Such materials can be used as anode‐active material in organic radical batteries (ORBs).

     

Engineering a Highly Regioselective Fungal Peroxygenase for the Synthesis of Hydroxy Fatty Acids

The hydroxylation of fatty acids is an appealing reaction in synthetic chemistry, although the lack of selective catalysts hampers its industrial implementation. In this study, we have engineered a highly regioselective fungal peroxygenase for the ω-1 hydroxylation of fatty acids with quenched stepwise over-oxidation. One single mutation near the Phe catalytic tripod narrowed the heme cavity, promoting a dramatic shift toward subterminal hydroxylation with a drop in the over-oxidation activity. While crystallographic soaking experiments and molecular dynamic simulations shed light on this unique oxidation pattern, the selective biocatalyst was produced by Pichia pastoris at 0.4 g L⁻¹ in a fed-batch bioreactor and used in the preparative synthesis of 1.4 g of (ω-1)-hydroxytetradecanoic acid with 95 % regioselectivity and 83 % ee for the S enantiomer.     

一种高稳定性合成直链烷基苯催化剂

以具有中、大双孔结构的γ-Al2O3为载体制备了固载化AlCl3催化剂,并在悬浮床反应器中考察了其苯与1-C1=2烷基化反应活性。结果表明,该催化剂具有较高的转化率、选择性和催化稳定性。在1000小时连续反应过程中,烯烃转化率高于94%,单烷基苯选择性达到92%,其中2-苯基异构体选择性为42%。     

Combining Electronic and Steric Effects for Highly Stable Unsymmetric Pentacenes

This paper describes the reactivity of unsymmetrically substituted pentacenes to photochemical oxidation. Acenes in general, and pentacenes in particular, are a key family of compounds for a variety of organic electronics applications. The instability of many pentacene derivatives, particularly to oxidation, is an important restriction in their applicability. Several substitution strategies for decreasing the reactivity of pentacene exist, but these almost always involve symmetrically substituted derivatives, restricting the chemical space of structures from which to choose. In this paper, we demonstrate that combining electronic and steric effects yields highly stable unsymmetrically substituted pentacenes.     

N‐Iodosuccinimide: A Highly Effective Regioselective Reagent for Iodoesterification of Alkenes

A rapid, convenient, and efficient method has been achieved for regioselective iodoesterification of alkenes with aliphatic and aromatic acids, and protected amino acids in the presence of N‐iodosuccinimide (NIS) in nearly quantitative yields. Optically enriched iodohydrins have been achieved by LiAlH₄ (LAH) reduction of diastereoisomeric iodo esters.     

Several Rules for Treating Phenol Wastewater via Oxidation by O3/UV-formed Radicals

IntroductionA large amount of phenol wastewater comes fromdifferent sources with potential severe impact to life andenvironment.Phenol is a prototype poison,which istoxic to all living creatures.Phenol can coagulate pro-tein and devitalize cells,especiall…     

Monolithic Phosphate Interphase for Highly Reversible and Stable Zn Metal Anode

Zinc metal battery (ZMB) is promising as the next generation of energy storage system, but challenges relating to dendrites and corrosion of the zinc anode are restricting its practical application. Here, to stabilize Zn anode, we report a controlled electrolytic method for a monolithic solid-electrolyte interphase (SEI) via a high dipole moment solvent dimethyl methylphosphonate (DMMP). The DMMP-based electrolytes can generate a homogeneous and robust phosphate SEI (Zn₃(PO₄)₂ and ZnP₂O₆). Benefiting from the protecting impact of this in situ monolithic SEI, the zinc electrode exhibits long-term cycling of 4700 h and a high Coulombic efficiency 99.89 % in Zn|Zn and Zn|Cu cell, respectively. The full V₂O₅|Zn battery with DMMP-H₂O hybrid electrolyte exhibits a high capacity retention of 82.2 % following 4000 cycles under 5 A g⁻¹. The first success in constructing the monolithic phosphate SEI will open a new avenue in electrolyte design for highly reversible and stable Zn metal anodes.     

The Highly Regioselective Synthesis of Novel Imidazolidin-2-Ones via the Intramolecular Cyclization/Electrophilic Substitution of Urea Derivatives and the Evaluation of Their Anticancer Activity

A series of novel 4-(het)arylimidazoldin-2-ones were obtained by the acid-catalyzed reaction of (2,2-diethoxyethyl)ureas with aromatic and heterocyclic C-nucleophiles. The proposed approach to substituted imidazolidinones benefits from excellent regioselectivity, readily available starting materials and a simple procedure. The regioselectivity of the reaction was rationalized by quantum chemistry calculations and control experiments. The anti-cancer activity of the obtained compounds was tested in vitro.