6,228 results on '"Crown ethers"'
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2. Interfacial host–guest complexation for inverted perovskite solar cells.
- Author
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Ballestas, Kevin, Milić, Jovana V., and Ramírez, Daniel
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SOLAR cells , *PEROVSKITE , *ELECTRON transport , *CROWN ethers - Abstract
Perovskite solar cells have demonstrated exceptional development over the past decade, but their stability remains a challenge toward the application of this technology. Several strategies have been used to address this, and the use of host–guest complexation has recently attracted more interest. However, this approach has primarily been exploited in conventional perovskite solar cells based on n-i-p architectures, while its use in inverted p-i-n devices remains unexplored. Herein, we employ representative crown ether, dibenzo-24-crown-8, for interfacial host–guest complexation in inverted perovskite solar cells based on methylammonium and methylammonium-free formamidinium-cesium halide perovskite compositions. Upon post-treatment of the perovskite films, we observed nanostructures on the surface that were associated with the reduced amount of trap states at the interface with the electron transport layer. As a result, we demonstrate improved efficiencies and operational stabilities following ISOS-D-2I and ISOS-L-2I protocols, demonstrating the viability of this approach to advance device stability. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Competition of intermolecular interactions in the self-assembly of co-crystals of trifluoro-meta-arylenediamines (benzene, nitrobenzene, pyridine) with 12-, 15-, and 18-membered crown ethers.
- Author
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Vaganova, Tamara, Gatilov, Yurij, Kryuchkova, Natalia, Pishchur, Denis, and Malykhin, Evgenij
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INTERMOLECULAR interactions , *CROWN ethers , *ELECTRON affinity , *NITROBENZENE , *MOLECULAR crystals , *BENZENE - Abstract
Two sets of co-formers, polyfluorinated arylenediamines with variable structural elements and macrocyclic ethers of different sizes, were used to study the patterns of self-assembly of co-crystals and to rank the intermolecular interactions. The co-crystallization stoichiometry was found to increase from 1 : 1 to 2 : 1 in the series trifluoro-1,3-phenylenediamine, 2,4-diaminotrifluoropyridine, and 2,4-diaminotrifluoronitrobenzene and with decreasing crown ether size due to restructuring of guest--host interactions and forming guest-guest interactions. 18-Crown-6 and 15-crown-5 ethers form the typical N--H...Ocr H-bonds connecting two Ocr atoms with one bifunctional proton donor NH2; when going to 12-crown-4, two Ocr atoms become connected with the Hamino atoms of two arylenediamine molecules. Modes of guest--guest bonding and supramolecular motifs in 2 : 1 co-crystals are determined by HB acceptors and p + π systems in arylenediamine: o-N--H...Nhet and p-N--H...F interactions form face-to-face dimers united in a chain; p-N-H...Onitro and o-N--H...Onitro contacts generate head-to-tail and head-to-side chains; π...π and X...π (X = F, O, N) electron interactions form off-set stacks. Quantum chemical calculations reveal an increase of the packing enthalpies and bonding energies with increasing arylenediamine electron affinity and crown ether size. According to MEP, BCP and NCI analyses, these effects are caused either by strengthening of the interactions due to a greater electrostatic contribution, or by multiplying bonding contacts. Quantifying the interactions allowed us to identify the key supramolecular synthons and related elements of the co-former structure, which can serve as tools in the molecular crystal design. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Fabrication of Azacrown Ether‐Embedded Covalent Organic Frameworks for Enhanced Cathode Performance in Aqueous Ni−Zn Batteries.
- Author
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Chen, Qing, Lin, Mengdi, Li, Xia, Du, Zhenglin, Liu, Yandie, Tang, Yisong, Yan, Yong, and Zhu, Kelong
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CROWN ethers , *ALKALINE batteries , *CATHODES , *CRYSTALLINITY , *CATALYSIS - Abstract
Crown ethers (CEs), known for their exceptional host–guest complexation, offer potential as linkers in covalent organic frameworks (COFs) for enhanced performance in catalysis and host–guest binding. However, their highly flexible conformation and low symmetry limit the diversity of CE‐derived COFs. Here, we introduce a novel C3‐symmetrical azacrown ether (ACE) building block, tris(pyrido)[18]crown‐6 (TPy18C6), for COF fabrication (ACE‐COF‐1 and ACE‐COF‐2) via reticular synthesis. This approach enables precise integration of CEs into COFs, enhancing Ni2+ ion immobilization while maintaining crystallinity. The resulting Ni2+‐doped COFs (Ni@ACE‐COF‐1 and Ni@ACE‐COF‐2) exhibit high discharge capacity (up to 1.27 mAh ⋅ cm−2 at 8 mA ⋅ cm−2) and exceptional cycling stability (>1000 cycles) as cathode materials in aqueous alkaline nickel‐zinc batteries. This study serves as an exemplar of the seamless integration of macrocyclic chemistry and reticular chemistry, laying the groundwork for extending the macrocyclic‐synthon driven strategy to a diverse array of COF building blocks, ultimately yielding advanced materials tailored for specific applications. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Effect of supramolecular complexation of alkali hydrogenselenates with crown ethers and solid-solutions with their hydrogensulfate counterparts on the solid-to-solid phase transition behaviors.
- Author
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Ocak, Samet, Braga, Dario, and d'Agostino, Simone
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PHASE transitions , *X-ray powder diffraction , *CROWN ethers , *DIFFERENTIAL scanning calorimetry , *SINGLE crystals , *SOLID solutions - Abstract
This study investigates the structural and phase transition characteristics of supramolecular complexes composed of 18-crown-6 ether and hydrogen selenate (HSeO4−) anions with various cations (K+, Rb+, Cs+). Single crystals of [18-crown-6·K]HSeO4·2H2O, [18-crown-6·Rb]HSeO4·H2O, [18-crown-6·Cs]HSeO4·H2O, [18-crown-6·K]HSeO4, and [18-crown-6·K](HSeO4)0.5(HSO4)0.5 were grown and their structures determined via single-crystal X-ray diffraction. Differential scanning calorimetry and variable-temperature powder X-ray diffraction were employed to analyse dehydration and phase transition behaviors. The inclusion of 18-crown-6 ether significantly lowered the superprotonic phase transition temperatures by approximately 40 °C compared to pure solid acids. Additionally, substituting HSO4− with HSeO4− decreased phase transition temperatures for K and Cs-complexes and modified the phase transition behavior of the Rb-complex from two-step to single-step isostructural phase transition. Attempts to form solid solutions between the HSeO4− and HSO4− complexes yielded mixed results, with notable success in modulating phase transition temperatures in K-complexes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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6. Supramolecular channels via crown ether functionalized polyaniline for proton-self-doped cathode in aqueous zinc-ion battery.
- Author
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Jiang, Chaoyan, Hu, Fang, Zhang, Hao, Tang, Yixin, Shu, Jie, and Yue, Chuang
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CROWN ethers , *CATHODES , *DIFFUSION kinetics , *POLYANILINES , *ENERGY storage , *FUNCTIONAL groups , *PROTON transfer reactions - Abstract
[Display omitted] Polyaniline (PANI) has been widely used as a cathode in aqueous zinc-ion batteries (AZIBs) because of its attractive conductivity and energy storage capability. However, the extensive application of PANI is limited by spontaneous deprotonation and slow diffusion kinetics. Herein, an 18-crown-6-functionalised PANI pseudorotaxane (18C6@PANI) cathode is successfully developed through a facile template-directed polymerisation reaction. The 18C6@PANI cathode exhibits a high specific capacity of 256 mAh g−1 at 0.2 A/g, excellent rate performance of 134 mAh g−1 at 6 A/g and outstanding cycle stability at a high current density of 3 A/g over 10,000 cycles. Experimental and theoretical analyses demonstrate the formation of the –N–Zn–O– structure. The abundant supramolecular channels in pseudorotaxane, induced by crown ether functional groups, are beneficial for achieving superior cyclability and rate capability. These encouraging results highlight the potential for designing more efficient PANI-based cathodes for high-performance AZIBs. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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7. EFFECT OF CROWN ETHERS AND POLYGLYCOLS ON THE CATALYTIC OXIDATION OF CYCLOHEXANE AND ALKYLARENES.
- Author
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Melnyk, Yu. and Melnyk, S.
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TRANSITION metal ions ,CATALYTIC oxidation ,TRANSITION metal complexes ,REDUCTION potential ,TRANSITION metals ,CROWN ethers - Abstract
The effect of crown ethers and polyglycols on the liquid-phase oxidation of cyclohexane and alkylaromatic hydrocarbons (toluene and p-xylene) with molecular oxygen catalyzed by transition metal salts has been investigated. It has been determined that crown ethers increase the reaction rate at both low and high conversion levels of cyclohexane and alkylaromatic hydrocarbons. The additives under study primarily affect the selectivity of the oxidation products. Crown ether and polyglycol additives to cobalt naphthenate increase the cyclohexanone to cyclohexanol molar ratio in cyclohexane oxidation. The crown ether additives to cobalt acetate increase the selectivity for alcohol in the initial stage of toluene and p-xylene oxidation. At higher alkylarene conversion, the additives enhance the selectivity for carboxylic acids. We assume that crown ethers and polyglycols form complexes with transition metal ions, changing the redox potential of the ions. This change in redox potential affects both the reaction rate and the selectivity of the oxidation products. The study concludes that crown ether and polyglycol additives influence the stages of the catalytic liquid-phase oxidation of hydrocarbons. [ABSTRACT FROM AUTHOR]
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- 2024
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8. High-Performance Crown Ether-Modified Membranes for Selective Lithium Recovery from High Na + and Mg 2+ Brines Using Electrodialysis.
- Author
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Yin, Xiaochun, Xu, Pei, and Wang, Huiyao
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CROWN ethers ,MEMBRANE separation ,INFRARED spectroscopy ,IMPEDANCE spectroscopy ,HYDROGEN bonding ,ELECTRODIALYSIS - Abstract
The challenge of efficiently extracting Li
+ from brines with high Na+ or Mg2+ concentrations has led to extensive research on developing highly selective separation membranes for electrodialysis. Various studies have demonstrated that nanofiltration membranes or adsorbents modified with crown ethers (CEs) such as 2-OH-12-crown-4-ether (12CE), 2-OH-18-crown-6-ether (18CE), and 2-OH-15-crown-5-ether (15CE) show selectivity for Li+ in brines. This study aims to develop high-performance cation exchange membranes (CEMs) using CEs to enhance Li+ selectivity and to compare the performance of various CE-modified membranes for selective electrodialysis. The novel CEM (CR671) was modified with 12CE, 18CE, and 15CE to identify the optimal CE for efficient Li+ recovery during brine electrodialysis. The modification process included polydopamine (PDA) treatment and the deposition of polyethyleneimine (PEI) complexes with the different CEs via hydrogen bonding. Interfacial polymerization with 1,3,5-benzenetricarbonyl trichloride-crosslinked PEI was used to create specific channels for Li+ transport within the modified membranes (12CE/CR671, 15CE/CR671, and 18CE/CR671). The successful application of CE coatings and Li+ selectivity of the modified membranes were verified through Fourier-transform infrared spectroscopy, zeta-potential measurements, and electrochemical impedance spectroscopy. Bench-scale electrodialysis tests showed significant improvements in permselectivity and Li+ flux for all three modified membranes. In brines with high Na+ and Mg2+ concentrations, the 15CE/CR671 membrane demonstrated more significant improvements in permselectivity compared to the 12CE/CR671 (3.3-fold and 1.7-fold) and the 18CE/CR671 (2.4-fold and 2.6-fold) membranes at current densities of 2.3 mA/cm2 and 2.2 mA/cm2 , respectively. At higher current densities of 14.7 mA/cm2 in Mg2+ -rich brine and 15.9 mA/cm2 in Na+ -rich brine, the 15CE/CR671 membrane showed greater improvements in Li+ flux, approximately 2.1-fold and 2.3-fold, and 3.2-fold and 3.4-fold compared to the 12CE/CR671 and 18CE/CR671 membranes. This study underscores the superior performance of 15CE-modified membranes for efficient Li+ recovery with low energy demand and offers valuable insights for advancing electrodialysis processes in challenging brine environments. [ABSTRACT FROM AUTHOR]- Published
- 2024
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9. Contents list.
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KINETIC control , *BORENES , *CAREER development , *INDOLE compounds , *COUPLING reactions (Chemistry) , *ISOQUINOLINE , *SUPRAMOLECULAR polymers , *CROWN ethers , *SECONDARY amines - Abstract
The document is the contents list for an issue of the journal Chemical Communications. It includes the titles and authors of various articles and features that will be included in the issue. The articles cover a range of topics in the field of chemistry, including recent advances in biosensing systems, continuous flow synthesis, electrochemical construction, and more. The journal is published by The Royal Society of Chemistry, a leading chemistry community. [Extracted from the article]
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- 2024
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10. Scalable organocatalytic one pot asymmetric Strecker reaction via camphor sulfonyl functionalized crown-ether-tethered calix[4]arene.
- Author
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Malik, Apoorva, Antil, Kirti, Singh, Nikhil, Sharma, Pragati R., and Sharma, Rakesh K.
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DRUG synthesis , *PLATELET aggregation inhibitors , *CROWN ethers - Abstract
In this communication, we designed a highly selective camphor sulfonyl functionalized crown-ether-tethered calix[4]arene-derived organocatalyst for asymmetric Strecker reaction to provide the desired cyano adducts in high yields (∼99.9% yield) and enantioselectivities (up to 99.3% ee). Furthermore, 2 step facile syntheses of the antiplatelet drug (S)-clopidogrel exemplify the potential of this method for the preparation of commercial compounds. [ABSTRACT FROM AUTHOR]
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- 2024
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11. TPE-embedded butterfly bis-crown ether with controllable conformation and supramolecular chiroptical property.
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Tian, Xueqi, Zuo, Minzan, Shen, Yuhong, Mao, Ni, Wang, Kaiya, Sheng, Yanshan, Velmurugan, Krishnasamy, Jiao, Jianmin, and Hu, Xiao-Yu
- Subjects
CONFORMATIONAL isomers ,SUPRAMOLECULAR chemistry ,MOLECULAR conformation ,CIRCULAR dichroism ,SODIUM ions ,CROWN ethers - Abstract
Understanding how subtle structural differences between macrocyclic conformational isomers impact their properties and separation has garnered increasing attention in the field of supramolecular synthetic chemistry. In this work, a series of tetraphenylene (TPE)-embedded butterfly bis-crown ether macrocycles (BCE[n], n = 4–7), comprising two crown ether side rings and a TPE core, are synthesized through intramolecular McMurry coupling. Unexpectedly, the presence of flexible oligoethylene chains with varying lengths are found to influence molecular conformation via multiple intramolecular interactions, resulting in the formation of two stabilized conformers with specific semi-rigid symmetric/asymmetric structures (sym-BCE[n] and asym-BCE[n], n = 5, 6). Moreover, it is noteworthy that neither symmetric nor asymmetric conformers are present in the more rigid BCE[4] or the more flexible BCE[7]. Interestingly, these conformers display distinct fluorescence properties and host-guest binding abilities, and only sym-BCE[5] can serve as a host for chiral polymer binding, resulting in the formation of chiral supramolecular assemblies through host-guest interaction induced chirality. Moreover, both circular dichroism and circularly polarized luminescence signals of the obtained assemblies can be switched off by the addition of sodium ion, suggesting potential applications in the field of dynamic chiral materials. Understanding how structural differences impact the properties of macrocyclic conformational isomers has garnered attention in the field of supramolecular chemistry. Here, the authors synthesize tetraphenylene-embedded butterfly bis-crown ether macrocycles with conformers that display distinct fluorescence properties and host-guest binding abilities. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Macrocycle-Based Supramolecular Drug Delivery Systems: A Concise Review.
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Yang, Yanrui, Li, Pengcheng, Feng, Haibo, Zeng, Rui, Li, Shanshan, and Zhang, Qixiong
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DRUG delivery systems , *MACROCYCLIC compounds , *CROWN ethers , *DRUG bioavailability , *CHEMICAL properties - Abstract
Efficient delivery of therapeutic agents to the lesion site or specific cells is an important way to achieve "toxicity reduction and efficacy enhancement". Macrocycles have always provided many novel ideas for drug or gene loading and delivery processes. Specifically, macrocycles represented by crown ethers, cyclodextrins, cucurbit[n]urils, calix[n]arenes, and pillar[n]arenes have unique properties, which are different cavity structures, good biocompatibility, and good stability. Benefited from these diverse properties, a variety of supramolecular drug delivery systems can be designed and constructed to effectively improve the physical and chemical properties of guest molecules as needed. This review provides an outlook on the current application status and main limitations of macrocycles in supramolecular drug delivery systems. [ABSTRACT FROM AUTHOR]
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- 2024
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13. Benzo‐Crown‐Ether Functionalized O‐BODIPY Probes for Cations – A Selective Fluorescent Probe for Ba2+.
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Sprenger, Tobias, Schwarze, Thomas, Holdt, Hans‐Jürgen, Hentsch, Axel, and Nazaré, Marc
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FLUORESCENCE yield , *PHOTOINDUCED electron transfer , *FLUORESCENT probes , *CROWN ethers , *FLUORESCENCE quenching - Abstract
Herein, we report the synthesis and sensing characteristics of 4,4′‐methoxy‐substituted BODIPY fluorescent probes (O‐BODIPYs) 3, 4 and 5 equipped with differently sized benzo‐crown ethers (cf. Scheme 1, 3 (benzo‐15‐crown‐5), 4 (benzo‐18‐crown‐6) and 5 (benzo‐21‐crown7)). O‐BODIPYs 3, 4 and 5 exhibited in comparison to their known F‐BODIPY analogues 3a, 4a and 5a (cf. Scheme 1) an improved solubility in aqueous medium and higher fluorescence quantum yields. Fluorometric study in aqueous solutions of 3, 4 and 5 in the presence of different cations show cation induced fluorescence enhancements (FE). Compared to the benzo‐crown ether substituted F‐BODIPY analogues 3a, 4a and 5a, we found for the free O‐BODIPYs 3, 4 and 5 higher fluorescence quantum yields (φf) but lower cation induced FEs. We show that in aqueous medium the fluorescence quenching process (OFF switching), a photoinduced electron transfer, in O‐BODIPYs 3, 4 and 5 is less effective and consequently sensitive and selective ON switching of the fluorescence by cations, too. Albeit these observations the novel benzo‐21‐crown‐7 equipped fluorescent probe 5 exhibits a good fluorometric Ba2+ selectivity and Ba2+ sensitivity in conjunction to their aqueous solubility. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Benzo‐Crown‐Ether Functionalized O‐BODIPY Probes for Cations – A Selective Fluorescent Probe for Ba2+.
- Author
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Sprenger, Tobias, Schwarze, Thomas, Holdt, Hans‐Jürgen, Hentsch, Axel, and Nazaré, Marc
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FLUORESCENCE yield ,PHOTOINDUCED electron transfer ,FLUORESCENT probes ,CROWN ethers ,FLUORESCENCE quenching - Abstract
Herein, we report the synthesis and sensing characteristics of 4,4′‐methoxy‐substituted BODIPY fluorescent probes (O‐BODIPYs) 3, 4 and 5 equipped with differently sized benzo‐crown ethers (cf. Scheme 1, 3 (benzo‐15‐crown‐5), 4 (benzo‐18‐crown‐6) and 5 (benzo‐21‐crown7)). O‐BODIPYs 3, 4 and 5 exhibited in comparison to their known F‐BODIPY analogues 3a, 4a and 5a (cf. Scheme 1) an improved solubility in aqueous medium and higher fluorescence quantum yields. Fluorometric study in aqueous solutions of 3, 4 and 5 in the presence of different cations show cation induced fluorescence enhancements (FE). Compared to the benzo‐crown ether substituted F‐BODIPY analogues 3a, 4a and 5a, we found for the free O‐BODIPYs 3, 4 and 5 higher fluorescence quantum yields (φf) but lower cation induced FEs. We show that in aqueous medium the fluorescence quenching process (OFF switching), a photoinduced electron transfer, in O‐BODIPYs 3, 4 and 5 is less effective and consequently sensitive and selective ON switching of the fluorescence by cations, too. Albeit these observations the novel benzo‐21‐crown‐7 equipped fluorescent probe 5 exhibits a good fluorometric Ba2+ selectivity and Ba2+ sensitivity in conjunction to their aqueous solubility. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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15. Halogen bonded associates of iodonium salts with 18-crown-6: does structural flexibility or structural rigidity of the σ-hole donor provide efficient substrate ligation?
- Author
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Sysoeva, Alexandra A., Novikov, Alexander S., Il'in, Mikhail V., and Bolotin, Dmitrii S.
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IODONIUM salts , *HALOGENS , *BINDING constant , *CROWN ethers , *IODINE , *CYCLIC ethers , *ATOMS in molecules theory - Abstract
1H NMR titration of 18-crown-6 with diphenyliodonium triflate and dibenziodolium triflate indicated that the acyclic iodine(III)-containing species has a higher binding constant value compared with the cyclic analogue. Formation of triple associates diphenyliodonium⋯18-crown-6⋯diphenyliodonium was observed in CD3CN. DFT calculations and QTAIM analysis indicated that the acyclic iodonium salt forms a higher number of interactions with the crown ether compared with the cyclic cation, which results in the formation of triple associates. The formation of dibenziodolium⋯18-crown-6⋯dibenziodolium triple associates turned out to be energetically unfavorable, which agrees with the experimentally obtained data. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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16. Supramolecular Assembly of Cesium Copper Iodine Resulting in Rich Emission Properties.
- Author
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Jiang, Meifeng, Lu, Xinle, Chen, Maosheng, Tong, Wenyi, Lin, Hechun, Luo, Chunhua, Peng, Hui, and Duan, Chungang
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ENERGY levels (Quantum mechanics) , *CROWN ethers , *METAL halides , *EXCITED states , *CESIUM , *COPPER - Abstract
Crown ether‐assisted supramolecular assembly is a robust strategy for manipulating low‐dimensional metal halides. In this study, the supramolecular assembly of 0D‐Cs3Cu2I5 is presented. Upon the addition of 15‐crown‐5 (15C5) to Cs3Cu2I5, 15C5 immediately coordinates with Cs+ to form the cone‐shaped [(15C5)Cs]+. Simultaneously, one of the iodine atoms is removed from the [Cu2I5]3‐ cluster, resulting in the formation of a sub‐planar rhombic [Cu2I4]2− unit. This process leads to white emission, specifically [(15C5)Cs]2[Cu2I4], which exhibits a photoluminescence quantum yield (PLQY) close to unity. The [(15C5)Cs]+ further reacts with 15C5 to form the sandwich‐type cationic structure [(15C5)2Cs]+, accompanied by the generation of red emission [(15C5)2Cs]2[Cu2I4]. By carefully controlling the amount of 15C5, various emission composites can be achieved, particularly tunable white emission. The assembly process is reversible. The pristine Cs3Cu2I5 can be recovered after thermal curing because of the volatility of crown ether and the weak Cs‐crown ether bond. Theoretical calculations have demonstrated that the coordination of the crown ether primarily affects the energy level, leading to changes in the excited state and photophysical properties. The applications in anticounterfeiting and LED phosphors have been demonstrated. This work provides a new approach for the development of low‐dimensional copper halides with promising applications in optoelectronics. [ABSTRACT FROM AUTHOR]
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- 2024
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17. Dynamic control of circumrotation of a [2]catenane by acid‐base switching.
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Shi, Kelun, Jia, Guohui, Wu, Ying, Zhang, Shilong, and Chen, Jiawen
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CROWN ethers , *SALTS , *MOLECULES , *MACHINERY - Abstract
Dynamic control of the motion in a catenane remains a big challenge as it requires precise design and sophisticated well‐organized structures. This paper reports the design and synthesis of a donor‐acceptor [2]catenane through mechanical interlocking, employing a crown ether featuring two dibenzylammonium salts on its side arms as the host and a cyclobis(paraquat‐p‐phenylene) (CBPQT ⋅ 4PF6) ring as the guest molecule. By addition of external acid or base, the catenane can form self‐complexed or decomplexed compounds to alter the cavity size of the crown ether ring, consequently affecting circumrotation rate of CBPQT ⋅ 4PF6 ring of the catenane. This study offers insights for the design and exploration of artificial molecular machines with intricate cascading responsive mechanisms. [ABSTRACT FROM AUTHOR]
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- 2024
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18. All‐Weather Solar‐Powered Desalination and Synchronous Cs+ Extraction for Salt‐Lake Water Enabled by Crown‐Ether‐Decorated Phase‐Change Microcapsules.
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Zhang, Hongyu, Zhou, Shiliang, Liu, Huan, Qian, Zhiqiang, and Wang, Xiaodong
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CESIUM ions , *CESIUM , *SALINE water conversion , *HEAT storage , *TECHNOLOGICAL innovations , *CROWN ethers , *PHASE change materials , *ENERGY harvesting - Abstract
Solar‐powered interfacial evaporation is recognized as an emerging technology for desalination of salt‐lake water but suffers from insufficient evaporation mass under intermittent sunlight illumination. Meanwhile, salt‐lake water contains abundant noble metal ions; however, there is no effective strategy to extract them during evaporation. Hereby, an interfacial evaporator integrated with crown‐ether‐functionalized phase‐change microcapsules (Crown‐MicPCM) is designed to realize all‐weather desalination and synchronous caesium ion (Cs+) extraction of salt‐lake water. Crown‐MicPCM is constructed with an
n ‐docosane core for photothermal energy storage, a magnetic SiO2/Fe3O4 composite shell for easy recyclability, a polydopamine inner coat for sunlight absorption, and a crown ether outer coat for selective Cs+ adsorption. Through integrating the functions of solar energy harvest, latent heat storage, and selective Cs+ adsorption within Crown‐MicPCM, such an innovative design boosts the evaporation and adsorption performance of the developed evaporator significantly. The developed Crown‐MicPCM‐integrated evaporator exhibits a considerable improvement in freshwater production and Cs+ extraction, achieving a Cs+ adsorption capacity of 32.6 mg g−1 and an evaporation rate of 1.43 kg m−2 h−1 under one‐sun illumination. Compared with the evaporator without a phase‐change material, the Crown‐MicPCM‐integrated evaporator obtains an increase in freshwater yield by 47% and in adsorption efficiency of Cs+ by 12% under natural sunlight illumination. [ABSTRACT FROM AUTHOR]- Published
- 2024
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19. Comprehensively understanding the distinct properties of crystal structure, phase transition and dielectrics in [M(crown)n]ReO4 (M+ = Na+, K+, NH4+; crown = 15-crown-5, 18-crown-6; n = 1 or 2)
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Yuan, Guo-Jun, Pan, Xue-Wei, Gao, Yan, Jiang, You-Fang, Li, Li, and Ren, Xiao-Ming
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PHASE transitions , *REVERSIBLE phase transitions , *CRYSTAL structure , *DIELECTRICS , *CROWN ethers , *X-ray powder diffraction - Abstract
In this study, three supramolecular compounds, namely [Na(18-crown-6)]ReO4 (1), [K(18-crown-6)]ReO4 (2) and [NH4(15-crown-5)2]ReO4 (3) were synthesized and characterized using microanalysis, thermogravimetric, differential scanning calorimetric and powder X-ray diffraction techniques, among others. Herein, 15-crown-5 and 18-crown-6 represent 1,4,7,10,13-pentaoxacyclopentadecane and 1,4,7,10,13,16-hexaoxacyclooctadecane, respectively. Both 1 and 2 experienced one-step reversible phase transition at ∼436 K and ∼360 K, respectively, while 3 underwent three steps of reversible phase transitions at ∼289 K, ∼352 K and ∼380 K. A dielectric anomaly occurred at ∼433 K (∼363 K) for 1 (2), consistent with the temperature obtained from DSC measurement. In the dielectric spectra of 3, anomalies were observed at ∼386 K and ∼433 K, corresponding to two thermal anomalies observed at higher temperatures in the DSC plot. However, there was an absence of dielectric response around 289 K where a thermal anomaly appeared in the DSC plot. The distinct crystal structures, phase transitions and dielectric properties in 1–3 stem from the degree of compatibility between the radii of M+ (Na+, K+ and NH4+) and the ring sizes of crown ethers (18-crown-6 and 15-crown-5). [ABSTRACT FROM AUTHOR]
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- 2024
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20. Pressure‐Induced Encapsulation of Cs+ Cations within an 18‐Crown‐6 Cavity: Insights from X‐ray Diffraction, Raman Spectroscopy, and DFT Calculations.
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Rusanov, Eduard B., Wörle, Michael D., Kovalenko, Maksym V., Domasevitch, Kostiantyn V., and Rusanova, Julia A.
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RAMAN spectroscopy , *X-ray diffraction , *DIAMOND anvil cell , *UNIT cell , *CELL size , *CROWN ethers - Abstract
This study utilizes single‐crystal X‐ray diffraction in a diamond anvil cell (DAC) to explore the structural response of [Cs(18‐Crown‐6)][SbCl6] under high pressure (HP). Notably, the pressure drives large Cs atoms closer to the center of the crown ether cavity, ultimately requiring pressures of 3 GPa for its complete encapsulation. Remarkably, the absence of short contacts in the crystal classifies the material as a "loose crystal" offering a unique model for understanding compression mechanisms. The crystal exhibits highly anisotropic compression behavior with an impressive volume reduction and non‐linear pressure – unit‐cell parameters relationships facilitated by the absence of short CH⋅⋅⋅Cl contacts up to 0.9 GPa. Beyond this pressure, steric repulsion due to shortening H⋅⋅⋅Cl and H⋅⋅⋅H interactions hinders further effective compression, so pressure dependence on unit cell parameters and volume becomes more linear. The behavior of [Cs(18‐Crown‐6)][SbCl6] at different conditions was studied using Raman spectroscopy and supplemented by DFT calculations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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21. Polyethylene glycol: an efficient solid–liquid transfer agent for K2CO3-catalyzed oxidative coupling reaction of alkyl mercaptan with sulfur as oxidant.
- Author
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Jiang, Shan, Wang, Rui, Jin, Changzi, Li, Fei, and Jiang, Heng
- Subjects
- *
COUPLING reactions (Chemistry) , *OXIDATIVE coupling , *CHEMICAL yield , *SULFUR , *CROWN ethers , *HYDROXYL group , *DISULFIDES , *POLYETHYLENE glycol - Abstract
The solid–liquid phase transfer catalyzed (S-L PTC) properties of polyethylene glycol (PEG) were investigated in the preparation of dialkyl disulfide (R2S2) by oxidative coupling of alkyl mercaptan and sulfur with K2CO3 as catalyst under atmospheric pressure and solvent-free conditions. The results have showed that the S-L PTC properties of PEG are not significantly different from those of crown ether. The S-L PTC properties of PEG are reduced due to methylation of the terminal hydroxyl groups, indicating that the terminal hydroxyl group in PEG plays an important role in stabilizing the [PEG-K2+ CO32−] complex. The results of infrared spectral analysis confirm that CO32− in K2CO3 has a strong interaction with the terminal hydroxyl group in PEG. At the fixed molar ratio of –CH2CH2O-/K2CO3, the increase of PEG chain length has a positive correlation with the S-L PTC performance. The reaction rate and yield of R2S2 can be improved by increasing the amount of K2CO3 and the molar ratio of -CH2CH2O-/K2CO3 appropriately. The PEG400/K2CO3 system exhibits very high catalytic activity for the oxidative coupling reaction of alkyl mercaptan with sulfur as oxidant. The yield of the reaction product (n-C8H17)2S2 can still reach more than 97% by using 0.1 mol% K2CO3 and 0.006 mol% PEG400 (based on sulfur). [ABSTRACT FROM AUTHOR]
- Published
- 2024
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22. Crown Ether Electrolyte Induced Li2O2 Amorphization for Low Polarization and Long Lifespan Li‐O2 Batteries.
- Author
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Li, Meng, Wu, Jiaxin, You, Zichang, Dai, Zhongqin, Gu, Yuanfan, Shi, Lei, Wu, Meifen, and Wen, Zhaoyin
- Subjects
- *
LITHIUM-air batteries , *AMORPHIZATION , *LITHIUM cells , *ELECTROLYTES , *STORAGE batteries , *ENERGY density , *ELECTRIC batteries , *CROWN ethers - Abstract
Lithium‐oxygen batteries possess an extremely high theoretical energy density, rendering them a prime candidate for next‐generation secondary batteries. However, they still face multiple problems such as huge charge polarization and poor life, which lay a significant gap between laboratory research and commercial applications. In this work, we adopt 15‐crown‐5 ether (C15) as solvent to regulate the generation of discharge products in lithium‐oxygen batteries. The coronal structure endows C15 with strong affinity to Li+, firmly stabilizes the intermediate LiO2 and discharge product Li2O2. Thus, the crystalline Li2O2 is amorphized into easily decomposable amorphous products. The lithium‐oxygen batteries assembled with 0.5 M C15 electrolyte show an increased discharge capacity from 4.0 mAh cm−2 to 5.7 mAh cm−2 and a low charge overpotential of 0.88 V during the whole lifespan at 0.05 mA cm−2. The batteries with 1 M C15 electrolyte can cycle stably for 140 cycles. Furthermore, the amorphous characteristic of Li2O2 product is preserved when matched with redox mediators such as LiI, with the charge polarization further decreasing to 0.74 V over a cycle life of 190 cycles. This provides new possibilities for electrolyte design to promote Li2O2 amorphization and reduce charge overpotential in lithium‐oxygen batteries. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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23. Superior sodiophilicity and molecule crowding of crown ether boost the electrochemical performance of all-climate sodium-ion batteries.
- Author
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Qian Yao, Cheng Zheng, Deluo Ji, Yingzhe Du, Jie Su, Nana Wang, Jian Yang, Shixue Dou, and Yitai Qian
- Subjects
- *
CROWN ethers , *SODIUM ions , *MOLECULES , *LITHIUM-ion batteries , *STORAGE batteries - Abstract
Sodium-ion batteries (SIBs) as one of the promising alternatives to lithium-ion batteries have achieved remarkable progress in the past. However, the all-climate performance is still very challenging for SIBs. Herein, 15-Crown-5 (15-C-5) is screened as an electrolyte additive from a number of ether molecules theoretically. The good sodiophilicity, high molecule rigidity, and bulky size enable it to reshape the solvation sheath and promote the anion engagement in the solvated structures by molecule crowding. This change also enhances Na-ion transfer, inhibits side reactions, and leads to a thin and robust solid-electrolyte interphase. Furthermore, the electrochemical stability and operating temperature windows of the electrolyte are extended. These profits improve the electrochemical performance of SIBs in all climates, much better than the case without 15-C-5. This improvement is also adopted to μ-Sn, μ-Bi, hard carbon, and MoS2. This work opens a door to prioritize the potential molecules in theory for advanced electrolytes. [ABSTRACT FROM AUTHOR]
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- 2024
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24. Studying Cation Exchange in {Cr7Co} Pseudorotaxanes: Preparatory Studies for Making Hybrid Molecular Machines.
- Author
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Bennett, Tom S., Geue, Niklas, Timco, Grigore A., Whitehead, George F. S., Vitorica‐Yrezabal, Inigo J., Barran, Perdita E., McInnes, Eric J. L., and Winpenny, Richard E. P.
- Subjects
- *
NUCLEAR magnetic resonance spectroscopy , *CATIONS , *MASS spectrometry , *CROWN ethers , *DYNAMICAL systems , *MACHINE design - Abstract
In the design of dynamic supramolecular systems used in molecular machines, it is important to understand the binding preferences between the macrocycle and stations along the thread. Here, we apply 1H NMR spectroscopy to investigate the relative stabilities of a series of linear alkylammonium templated pseudorotaxanes with the general formula [H2NRR'][Cr7CoF8(O2CCH2tBu)16] by exchanging the cation in solution. Our results show that the pseudorotaxanes are able to exchange threads via a dissociative mechanism. The position of equilibrium is dependent upon the ammonium cation and solvent used. Short chain primary ammonium cations are shown to be far less favourable macrocycle stations than secondary ammonium cations. Collision‐induced dissociation mass spectrometry (CID‐MS) has been used to look at disassembly of the pseudorotaxanes in a solvent‐free environment and stability trends compared to those in acetone‐d6. The energy needed to induce 50 % of the precursor ion loss (E50) is used and shows a similar trend to the equilibria measured by NMR. The relative stabilities of these hybrid inorganic‐organic pseudo‐rotaxanes are different to those of host‐guest compounds involving crown ethers and this may be valuable for the design of molecular machines. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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25. Copper‐kryptofix‐21‐Fe3O4/MCM‐41: A powerfully recoverable nanocatalyst for clean regioselective 1,2,3‐triazole synthesis‐click reactio n.
- Author
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Ojaghi Aghbash, Khadijeh and Noroozi Pesyan, Nader
- Subjects
- *
NANOPARTICLES , *POROUS materials , *COPPER , *ETHYNYL benzene , *CATALYTIC activity , *CROWN ethers - Abstract
A novel porous and magnetic nanoparticle, composed of Fe3O4/MCM‐41 functionalized with a kryptofix‐21 crown ether, has been successfully synthesized. This was achieved through the treatment of 3‐chloropropyl functionalized Fe3O4/MCM‐41 with the crown ether, followed by the grafting of Cu (II) onto the material, resulting in the formation of Fe3O4/MCM‐41/kryptofix‐21/Cu. The material's 2D‐hexagonally ordered mesophases were analyzed using small‐angle‐PXRD and TEM‐imaging. The Cu (II)‐anchored porous material, Fe3O4/MCM‐41/kryptofix‐21/Cu, exhibited remarkable catalytic activity in the Click reaction between azides and phenylacetylene, conducted in ethylene glycol/water at a temperature of 70 °C. This reaction led to the synthesis of a diverse range of 1,4‐disubstituted 1,2,3‐triazoles. The catalyst demonstrated excellent recyclability, maintaining its catalytic activity for up to eight cycles without any significant loss. Furthermore, no significant leaching of Cu was observed, highlighting the potential of this magnetically innovative nanoporous catalyst in the regioselective formation of 1,4‐disubstituted 1,2,3‐triazolic compounds. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. New pyridine dithiaazacrown ether derivatives: synthesis, structural characterization, in silico and in vitro biological studies.
- Author
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Tran, Van T.T., Dao, Nhung T., Do, Thuyen T., Pham, Tam T.T., Le, Duan T., Khrustalev, Victor N., Nguyen, Phuong T.T., and Le, Anh T.
- Subjects
- *
LIGANDS (Chemistry) , *ETHER synthesis , *COMPLEX compounds , *ETHER derivatives , *METAL ions , *CROWN ethers - Abstract
[Display omitted] New derivatives of dithiaazacrown ethers containing ψ-arylpyridine subunits were prepared based on the Hantzsch synthesis. The obtained compounds showed potential activities toward Hep-G2 cancer cell line, in both in silico and in vitro studies. The compounds were also good ligands for complex chemistry with metal ions due to possessing up to four heteroatoms and relatively big size of the crown ring. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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27. Six‐Cyclic Crown Ether‐Type Pillar[5]Arene: Enhanced Binding Ability to Bispyridinium Derivatives.
- Author
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Wu, Huai‐Li, Zhang, Meng‐Yang, Zhou, Ting, Zhang, Le‐Ping, Qi, Qiao‐Yan, Yang, Guan‐Yu, Yang, Bo, and Li, Zhan‐Ting
- Subjects
- *
ETHYLENE oxide , *ETHER derivatives , *VOLUMETRIC analysis , *AROMATIC compounds , *ETHERS , *CROWN ethers - Abstract
A six‐cyclic crown ether‐type pillar[5]arene was synthesized, and the five ethylene oxide loops were located outside the cavity and not affected by temperature changes which was confirmed by variable‐temperature NMR experiment in DMSO‐d6 and CDCl3 and 2D 1H−1H NOESY experiment in CDCl3. The six‐cyclic pillar[5]‐crown also showed greater binding ability of host‐guest with bis(pyridinium) derivatives than conventional alkoxy pillar[5]arenes that illustrated through 1H NMR titration spectroscopic experiment in acetone‐d6/CDCl3 (1 : 1) and UV‐vis titration experiments in CHCl3 at room temperature. The five benzocrown ethers at the periphery were able to bind metal cations by 1H NMR titration spectroscopic experiment in CD2Cl2/methanol‐d4(9 : 1). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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28. Liquid–liquid extraction of strontium from acidic solutions into ionic liquids using crown ethers.
- Author
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Houzar, Jan, Cubova, Katerina, Semelova, Miroslava, and Nemec, Mojmir
- Subjects
- *
IONIC solutions , *LIQUID-liquid extraction , *STRONTIUM , *IONIC liquids , *FISSION products , *CROWN ethers - Abstract
90Sr is one of the most monitored fission products. New efficient methods for strontium separation are therefore sought. Over the past 20 years, crown ethers solutions in ionic liquids (ILs) have been confirmed to efficiently extract strontium from acidic solutions. Despite all the work done in this field, the extraction mechanism is still not completely clear. Depending on experimental conditions, the extraction is believed to proceed either in the form of an ion-association complex [Sr·CE·(NO3)2] or via exchange between [Sr·CE]2+ and two IL cations. This work aims to study the influence of several extraction parameters and compare them with the presumed mechanisms. [ABSTRACT FROM AUTHOR]
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- 2024
- Full Text
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29. Wie Kationen Zellwände durchdringen.
- Author
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Meyer, Philipp and Banerji, Amitabh
- Subjects
POTASSIUM permanganate ,SOLVENTS ,MOLECULES ,CROWN ethers - Abstract
Copyright of Nachrichten aus der Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2024
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30. Access to 1,2,3-triphospholide ligands by reduction of di-tert-butyldiphosphatetrahedrane.
- Author
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Uttendorfer, Maria K., Hierlmeier, Gabriele, Balázs, Gábor, and Wolf, Robert
- Subjects
- *
ALKALI metals , *CROWN ethers , *TETRAHEDRAL molecules , *ALKALI metal ions , *SANDWICH construction (Materials) , *POTASSIUM salts , *ISOMERS - Abstract
Di-tert-butyldiphosphatetrahedrane (tBuCP)2 (A) is a reactive tetrahedral molecule which may serve as a source of new phosphaorganic molecules and ligands. However, the redox chemistry of this compound has not yet been investigated. Here, we show that the reduction of A with alkali metals (AM = Li, Na, K, Rb and Cs) affords 1,2,3-triphospholides [AM(crown ether)][1,2,3-P3C2tBu2] (1–5, [AM(crown ether)] = [Li([12]crown-4)2]+, [Na([15]crown-5)2]+, [K([18]crown-6)]+, [Rb([18]crown-6)]+, and Cs+) with 1,3-diphospholides [AM(crown ether)][1,3-P2C3tBu3] (6–10) formed as by-products. The potassium salt 3 was isolated on a preparative scale, allowing for reactivity studies. Transmetalation with iron(II) and ruthenium(II) chlorides yielded the sandwich complexes [Cp*M(η5-1,2,3-P3C2tBu2)] (11, M = Fe; 12, M = Ru, Cp* = C5Me5) featuring η5-coordinated triphospholide ligands. Treatment of 3 with [Cp2Fe][BAr4F] or [H(Et2O)2BAr4F] (BAr4F = B{C6H3(CF3)2}4) afforded the polyphosphorus compound tBu4C4P6 (13), which presumably results from the dimerisation of a 1,2,3-triphospholyl radical intermediate (1,2,3-P3C2tBu2)˙ (3˙). Tetracyclic 13 is closely structurally related to an isomer of the hydrocarbon hypostrophene (C10H10). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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31. Catalytic synthesis of flavanone without stirring or heating.
- Author
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Shigematsu, Karin, Toriyama, Masaharu, and Miura, Motofumi
- Subjects
- *
CROWN ethers , *ELECTRICAL energy , *CESIUM , *CHALCONES - Abstract
We developed a new approach for the synthesis of flavanone from chalcones without electrical energy, such as stirring or heating, by using a cesium fluoride–crown ether complex. This "zero electrical energy reaction" is a new category of reaction that has the potential to replace the general organic reaction. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. Crown ether-like octanuclear molybdenum(V) clusters for cation binding and gas adsorption.
- Author
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Ru-Dan Dai, Zhen-Lang Xie, Cheng Liu, Dong Xina, and Zhao-Hui Zhou
- Subjects
- *
GAS absorption & adsorption , *CROWN ethers , *MOLYBDENUM , *POROUS materials , *CATIONS , *HYDROGEN bonding - Abstract
Octanuclear polyoxomolybdenum-based porous materials, Na8[Mo8O8(µ2-O)8(µ2-OH)8(3-apz)4]2·26H2O (1, 3-Hapz = 3-aminopyrazole), K8[Mo8O8(µ2-O)8(µ2-OH)8(3-apz)4]2·7H2O (2) and (NH4)4[Mo8O8(µ2- O)8(µ2-OH)4(3-apz)8]·20.5H2O (3), have been successfully synthesized by a hydrothermal method and fully characterized. X-ray structural analyses show that microporous materials 1-3 contain round pores formed by octanuclear molybdenum-oxygen groups connected sequentially with pore sizes of 4.0, 4.0, and 4.8 Å, respectively. Both 1 and 2 are composed of two {Mo8} rings, which are connected by strong intramolecular hydrogen bonds between bridging hydroxy groups and oxygen atoms to form dimeric structures. The central pores in 1 and 2 are occupied by Na+ and K+, respectively, while they are empty in 3. This reflects the structural expansion and contraction effects induced by different cations. Through intermolecular stacking, 1-3 also exhibit channels with sizes of 14.0 × 6.4, 4.6 × 2.6, and 5.4 × 5.4 Å, respectively, which were used for the studies of gas adsorption. The results show that 1-3 can selectively adsorb CO2 and O2, including the empty hole in 3, while they show little or no affinity for gases H2, N2, and CH4. Moreover, an additional polyoxomolybdenum-based species (Mo8O26)n·4n(3-H2apz) (4) has been obtained with protonated 3-aminopyrazole in the absence of a reducing agent, which can serve as an intermediate for the polyoxomolybdenum-based porous products. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. A novel potentiometric screen-printed electrode based on crown ethers/nano manganese oxide/Nafion composite for trace level determination of copper ion in biological fluids.
- Author
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Hassan, Saad S. M., El-Shalakany, Hadeel H., Fathy, Mahmoud Abdelwahab, and Kamel, Ayman H.
- Subjects
- *
CROWN ethers , *COPPER ions , *MANGANESE oxides , *NAFION , *ALZHEIMER'S disease , *IONOPHORES - Abstract
Copper levels in biological fluids are associated with Wilson's, Alzheimer's, Menke's, and Parkinson's diseases, making them good biochemical markers for these diseases. This study introduces a miniaturized screen-printed electrode (SPE) for the potentiometric determination of copper(II) in some biological fluids. Manganese(III) oxide nanoparticles (Mn2O3-NPs), dispersed in Nafion, are drop-casted onto a graphite/PET substrate, serving as the ion-to-electron transducer material. The solid-contact material is then covered by a selective polyvinyl chloride (PVC) membrane incorporated with 18-crown-6 as a neutral ion carrier for the selective determination of copper(II) ions. The proposed electrode exhibits a Nernstian response with a slope of 30.2 ± 0.3 mV/decade (R2 = 0.999) over the linear concentration range 5.2 × 10–9 – 6.2 × 10–3 mol/l and a detection limit of 1.1 × 10–9 mol/l (69.9 ng/l). Short-term potential stability is evaluated using constant current chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS). A significant improvement in the electrode capacitance (91.5 μF) is displayed due to the use of Mn2O3-NPs as a solid contact. The presence of Nafion, with its high hydrophobicity properties, eliminates the formation of the thin water layer, facilitating the ion-to-electron transduction between the sensing membrane and the conducting substrate. Additionally, it enhances the adhesion of the polymeric sensing membrane to the solid-contact material, preventing membrane delamination and increasing the electrode's lifespan. The high selectivity, sensitivity, and potential stability of the proposed miniaturized electrode suggests its use for the determination of copper(II) ions in human blood serum and milk samples. The results obtained agree fairly well with data obtained by flameless atomic absorption spectrometry. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. Preparation of Two Novel Stable Silica-Based Adsorbents for Selective Separation of Sr from Concentrated Nitric Acid Solution.
- Author
-
Liu, Chang, Zhang, Shichang, Wang, Xinpeng, Chen, Lifeng, Yin, Xiangbiao, Hamza, Mohammed F., Wei, Yuezhou, and Ning, Shunyan
- Subjects
ACID solutions ,NITRIC acid ,SORBENTS ,CROWN ethers ,ADSORPTION capacity - Abstract
Crown ethers are famous for the highly selectively grab Sr(II) from concentrated nitric acid solution due to the size match, but they suffer from the high leakage into the liquid phase caused by the presence of a large number of hydrophilic groups. To reduce their leakage, two novel porous silica-based adsorbents, (DtBuCH18C6 + Dodec)/SiAaC-g-ABSA and (DtBuCH18C6 + Dodec)/SiAaC-g-3-ABSA, were prepared by vacuum impregnation with organic contents of about 55.9 wt.% and 56.1 wt.%, respectively. The two adsorbents have good reusability and structural stability, and the total organic carbon leakage rates in 2 M HNO
3 solution are lower than 0.56 wt.% and 0.29 wt.%, respectively. Batch adsorption experiments revealed that the two adsorbents possessed good adsorption selectivity towards Sr, with SFSr/M over 40, except that of SFSr/Ba in 2 M HNO3 solution. The adsorption equilibrium of Sr in 2 M HNO3 solution was reached within 1 h, with saturated adsorption capacities of 36.9 mg/g and 37.5 mg/g, respectively. Furthermore, the XPS results indicate that the adsorption mechanism is the coordination of the crown ether ring with Sr. This work not only develops two novel adsorbents for the separation of Sr in nitric acid environments; it also provides a method for effectively reducing the water solubility of crown ethers. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
35. A Solar and Seawater Co‐Involved Durable Rechargeable Battery Enabled by Crown Ether‐Rich Polymer‐Mediated Photoelectrodes.
- Author
-
Wang, Xiaotong, Li, Jing, Liu, Cong, Lin, Yi, Yang, Fan, Zhong, Linfeng, Zhang, Yang, and Yu, Dingshan
- Subjects
- *
STORAGE batteries , *SEAWATER , *CROWN ethers , *ELECTRODE reactions , *ENERGY conversion , *CHEMICAL kinetics , *SOIL corrosion - Abstract
The first flow‐type solar and seawater co‐mediated sodium‐air rechargeable battery (SSRB) for efficient solar‐to‐electrochemical energy conversion/storage is established. Such SSRB is enabled by a robust self‐regulated CEP/ZnWO4/WO3 heterojunction photoelectrochemical electrodes (PE) by passivating predesigned crown ether‐rich photoresponsive covalent organic polymer (CEP) layers onto ZnWO4‐modified WO3 nanosheet arrays. The PE design utilizes the previously‐unexplored self‐mediated effect of CEP to endow PE with superior stability, facilitated electrode reaction kinetics, and high efficiency of spatial charge separation simultaneously. This leads to remarkable light‐enhanced oxygen evolution catalysis with impressive photocurrent density up to 6.1 mA cm−2 at 1.23 V versus RHE in seawater – surpassing metal‐oxide‐based PEs ever reported for seawater splitting. Thus, the SSRB breaks the limit of the equilibrium voltage (3.47 V) of conventional seawater sodium‐air cells to deliver a low charge voltage of 2.71 V along with stable photo‐charge over 100 h and good photo‐charge/normal discharge cycling stability over 240 h – superior to almost all existing light‐involved air batteries. Combined experimental and modeling studies for the first time unveil the multi‐regulation effects of CEP passivation which prevents detrimental Cl‐corrosion, and promote oxygen evolution kinetics. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. Proximity Effects on the Reactivity of a Nonheme Iron (IV) Oxo Complex in C−H Oxidation.
- Author
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Fagnano, Alessandro, Frateloreto, Federico, Paoloni, Roberta, Sappino, Carla, Lanzalunga, Osvaldo, Costas, Miquel, Di Stefano, Stefano, and Olivo, Giorgio
- Subjects
- *
OXYGENASES , *ABSTRACTION reactions , *OXIDATION , *CROWN ethers , *IRON , *PHYSICAL organic chemistry - Abstract
Precise control of substrate positioning and orientation (its proximity to the reactive unit) is often invoked to rationalize the superior enzymatic reaction rates and selectivities when compared to synthetic models. Artificial nonheme iron (IV) oxo (Fe(IV)=O) complexes react with C(sp3)−H bonds via a biomimetic Hydrogen Atom Transfer/Hydroxyl Rebound mechanism, but rates, site‐selectivity and even hydroxyl rebound efficiency (ligand rebound versus substrate radical diffusion) are smaller than in oxygenases. Herein, we quantitatively analyze how substrate binding modulates nonheme Fe(IV)=O reactivity by comparing rates and outcomes of C−H oxidation by a pair of Fe(IV)=O complexes that share the same first coordination sphere but only one contains a crown ether receptor that recognizes the substrate. Substrate binding makes the reaction intramolecular, exhibiting Michaelis–Menten kinetics and increased reaction rates. In addition, C−H oxidation occurs with high site selectivity for remote sites. Analysis of Effective Molarity reveals that the system operates at its maximal theoretical capability for the oxidation of these remote sites. Remarkably, substrate positioning also affects Hydroxyl Rebound, whose efficiency only increases on the sites placed in proximity by recognition. Overall, these observations provide evidence that supramolecular control of substrate positioning can effectively modulate the reactivity of oxygenases and its models. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Crown ether decorated silicon photonics for safeguarding against lead poisoning.
- Author
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Ranno, Luigi, Tan, Yong Zen, Ong, Chi Siang, Guo, Xin, Koo, Khong Nee, Li, Xiang, Wang, Wanjun, Serna, Samuel, Liu, Chongyang, Rusli, Littlejohns, Callum G., Reed, Graham T., Hu, Juejun, Wang, Hong, and Sia, Jia Xu Brian
- Subjects
LEAD poisoning ,LEAD exposure ,LEAD ,CROWN ethers ,PHOTONICS ,ORGANIC compounds - Abstract
Lead (Pb
2+ ) toxification is a concerning, unaddressed global public health crisis that leads to 1 million deaths annually. Yet, public policies to address this issue have fallen short. This work harnesses the unique abilities of crown ethers, which selectively bind to specific ions. This study demonstrates the synergistic integration of highly-scalable silicon photonics, with crown ether amine conjugation via Fischer esterification in an environmentally-friendly fashion. This realizes an integrated photonic platform that enables the in-operando, highly-selective and quantitative detection of various ions. The development dispels the existing notion that Fischer esterification is restricted to organic compounds, facilitating the subsequent amine conjugation for various crown ethers. The presented platform is specifically engineered for selective Pb2+ detection, demonstrating a large dynamic detection range, and applicability to field samples. The compatibility of this platform with cost-effective manufacturing indicates the potential for pervasive implementation of the integrated photonic sensor technology to safeguard against societal Pb2+ poisoning. Lead toxification in society is a public health crisis. The exposure to lead poisoning gives rise to a multitude of health issues. In this work, a chip-scale photonic platform that enables the highly quantitative detection of lead is demonstrated. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
38. The Cyanoketenyl Anion [NC3O]−.
- Author
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Krischer, Felix, Swamy, Varre S. V. S. N., Feichtner, Kai‐Stephan, Ward, Robert J., and Gessner, Viktoria H.
- Subjects
- *
LIGAND exchange reactions , *YLIDES , *ANIONS , *COMPLEX compounds , *SMALL molecules , *ORGANIC compounds , *CROWN ethers - Abstract
Cumulenes and heterocumulenes with three or more cumulative multiple bonds are usually reactive species that serve as valuable building blocks for more complex molecules but tend to isomerize or cyclize and therefore are difficult to isolate. Using a mild ligand exchange reaction at the carbon in α‐metalated ylides, we have now succeeded in the synthesis and gram‐scale isolation of the elusive cyanoketenyl anion [NC3O]−. Despite its assumed cumulene‐like structure and the delocalization of the negative charge across the whole 5‐atom molecule, it features a bent geometry with a nucleophilic central carbon atom. Computational studies reveal an ambiguous bonding situation in the anion, which can be illustrated only by a combination of different resonance structures. Nonetheless, the anion features remarkable stability, thus allowing the storage of its potassium‐crown ether salt and its application as a highly functional synthetic building block. The cyanoketenyl anion readily reacts with a series of small molecules to form more complex organic compounds, including industrially valuable compounds such as cyanoacetate. This work demonstrated that reactive species can be generated by novel synthesis methods and open up atom‐economic pathways to complex compounds from small abundant molecules. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
39. The Cyanoketenyl Anion [NC3O]−.
- Author
-
Krischer, Felix, Swamy, Varre S. V. S. N., Feichtner, Kai‐Stephan, Ward, Robert J., and Gessner, Viktoria H.
- Subjects
- *
LIGAND exchange reactions , *YLIDES , *ANIONS , *COMPLEX compounds , *SMALL molecules , *ORGANIC compounds , *CROWN ethers - Abstract
Cumulenes and heterocumulenes with three or more cumulative multiple bonds are usually reactive species that serve as valuable building blocks for more complex molecules but tend to isomerize or cyclize and therefore are difficult to isolate. Using a mild ligand exchange reaction at the carbon in α‐metalated ylides, we have now succeeded in the synthesis and gram‐scale isolation of the elusive cyanoketenyl anion [NC3O]−. Despite its assumed cumulene‐like structure and the delocalization of the negative charge across the whole 5‐atom molecule, it features a bent geometry with a nucleophilic central carbon atom. Computational studies reveal an ambiguous bonding situation in the anion, which can be illustrated only by a combination of different resonance structures. Nonetheless, the anion features remarkable stability, thus allowing the storage of its potassium‐crown ether salt and its application as a highly functional synthetic building block. The cyanoketenyl anion readily reacts with a series of small molecules to form more complex organic compounds, including industrially valuable compounds such as cyanoacetate. This work demonstrated that reactive species can be generated by novel synthesis methods and open up atom‐economic pathways to complex compounds from small abundant molecules. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Perfect confinement of crown ethers in MOF membrane for complete dehydration and fast transport of monovalent ions.
- Author
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Tingting Xu, Bin Wu, Wenmin Li, Yifan Li, Yanran Zhu, Fangmeng Sheng, Qiuhua Li, Liang Ge, Xingya Li, Huanting Wang, and Tongwen Xu
- Subjects
- *
CROWN ethers , *FAST ions , *MEMBRANE separation , *ACTIVATION energy , *DEHYDRATION - Abstract
Fast transport of monovalent ions is imperative in selective monovalent ion separation based on membranes. Here, we report the in situ growth of crown ether@UiO-66 membranes at a mild condition, where dibenzo-18-crown-6 (DB18C6) or dibenzo-15-crown-5 is perfectly confined in the UiO-66 cavity. Crown ether@UiO-66 membranes exhibit enhanced monovalent ion transport rates and mono-/divalent ion selectivity, due to the combination of size sieving and interaction screening effects toward the complete monovalent ion dehydration. Specifically, the DB18C6@UiO-66 membrane shows a permeation rate (e.g., K+) of 1.2 mol per square meter per hour and a mono-/ divalent ion selectivity (e.g., K+/Mg2+) of 57. Theoretical calculations and simulations illustrate that, presumably, ions are completely dehydrated while transporting through the DB18C6@UiO-66 cavity with a lower energy barrier than that of the UiO-66 cavity. This work provides a strategy to develop efficient ion separation membranes via integrating size sieving and interaction screening and to illuminate the effect of ion dehydration on fast ion transport. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. The Cyanoketenyl Anion [NC3O]−.
- Author
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Krischer, Felix, Swamy, Varre S. V. S. N., Feichtner, Kai‐Stephan, Ward, Robert J., and Gessner, Viktoria H.
- Subjects
LIGAND exchange reactions ,YLIDES ,ANIONS ,COMPLEX compounds ,SMALL molecules ,ORGANIC compounds ,CROWN ethers - Abstract
Cumulenes and heterocumulenes with three or more cumulative multiple bonds are usually reactive species that serve as valuable building blocks for more complex molecules but tend to isomerize or cyclize and therefore are difficult to isolate. Using a mild ligand exchange reaction at the carbon in α‐metalated ylides, we have now succeeded in the synthesis and gram‐scale isolation of the elusive cyanoketenyl anion [NC3O]−. Despite its assumed cumulene‐like structure and the delocalization of the negative charge across the whole 5‐atom molecule, it features a bent geometry with a nucleophilic central carbon atom. Computational studies reveal an ambiguous bonding situation in the anion, which can be illustrated only by a combination of different resonance structures. Nonetheless, the anion features remarkable stability, thus allowing the storage of its potassium‐crown ether salt and its application as a highly functional synthetic building block. The cyanoketenyl anion readily reacts with a series of small molecules to form more complex organic compounds, including industrially valuable compounds such as cyanoacetate. This work demonstrated that reactive species can be generated by novel synthesis methods and open up atom‐economic pathways to complex compounds from small abundant molecules. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. The Cyanoketenyl Anion [NC3O]−.
- Author
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Krischer, Felix, Swamy, Varre S. V. S. N., Feichtner, Kai‐Stephan, Ward, Robert J., and Gessner, Viktoria H.
- Subjects
LIGAND exchange reactions ,YLIDES ,ANIONS ,COMPLEX compounds ,SMALL molecules ,ORGANIC compounds ,CROWN ethers - Abstract
Cumulenes and heterocumulenes with three or more cumulative multiple bonds are usually reactive species that serve as valuable building blocks for more complex molecules but tend to isomerize or cyclize and therefore are difficult to isolate. Using a mild ligand exchange reaction at the carbon in α‐metalated ylides, we have now succeeded in the synthesis and gram‐scale isolation of the elusive cyanoketenyl anion [NC3O]−. Despite its assumed cumulene‐like structure and the delocalization of the negative charge across the whole 5‐atom molecule, it features a bent geometry with a nucleophilic central carbon atom. Computational studies reveal an ambiguous bonding situation in the anion, which can be illustrated only by a combination of different resonance structures. Nonetheless, the anion features remarkable stability, thus allowing the storage of its potassium‐crown ether salt and its application as a highly functional synthetic building block. The cyanoketenyl anion readily reacts with a series of small molecules to form more complex organic compounds, including industrially valuable compounds such as cyanoacetate. This work demonstrated that reactive species can be generated by novel synthesis methods and open up atom‐economic pathways to complex compounds from small abundant molecules. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Molecular vessels from preorganised natural building blocks.
- Author
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Llamosí, Arturo, Szymański, Marek P., and Szumna, Agnieszka
- Subjects
- *
MULTIVALENT molecules , *CROWN ethers , *CYCLODEXTRINS , *BUILDING design & construction , *RESORCINOL , *METALLOPORPHYRINS , *CARBOHYDRATES - Abstract
Supramolecular vessels emerged as tools to mimic and better understand compartmentalisation, a central aspect of living matter. However, many more applications that go beyond those initial goals have been documented in recent years, including new sensory systems, artificial transmembrane transporters, catalysis, and targeted drug or gene delivery. Peptides, carbohydrates, nucleobases, and steroids bear great potential as building blocks for the construction of supramolecular vessels, possessing complexity that is still difficult to attain with synthetic methods – they are rich in functional groups and well-defined stereogenic centers, ready for noncovalent interactions and further functions. One of the options to tame the functional and dynamic complexity of natural building blocks is to place them at spatially designed positions using synthetic scaffolds. In this review, we summarise the historical and recent advances in the construction of molecular-sized vessels by the strategy that couples synthetic predictability and durability of various scaffolds (cyclodextrins, porphyrins, crown ethers, calix[n]arenes, resorcin[n]arenes, pillar[n]arenes, cyclotriveratrylenes, coordination frameworks and multivalent high-symmetry molecules) with functionality originating from natural building blocks to obtain nanocontainers, cages, capsules, cavitands, carcerands or coordination cages by covalent chemistry, self-assembly, or dynamic covalent chemistry with the ultimate goal to apply them in sensing, transport, or catalysis. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Crown Ether Copolymerized Polyimide Film: Enhanced Mechanical, Thermal Properties and Low Dielectric Constant under High Frequency.
- Author
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Li, Heming, Wang, Xinming, Ding, Ziyang, Gao, Weiguo, Liu, Yan, Ma, Ke, Hu, Zhizhi, and Wang, Yongqi
- Subjects
- *
POLYIMIDES , *PERMITTIVITY , *CROWN ethers , *POLYIMIDE films , *DIELECTRIC properties , *THERMAL properties - Abstract
Polymer materials with a low dielectric constant and low dielectric loss have the potential to be applied to high-frequency signal transmissions, such as mobile phone antennas and millimeter wave radars. Two types of diamines, 4,4′-diamino-p-tetraphenyl (DPT) and crown ether diamine (CED), were prepared for ternary copolymerization with BPDA in this study. Cross-links with molecular chains were formed, increasing molecular chain distance by utilizing rings of CED. The MPI films exhibit a good thermal performance with the increase in CED addition, with Tg > 380 °C and CTE from −4 × 10−6 K−1 to 5 × 10−6 K−1. The Young's modulus can reach 8.6 GPa, and the tensile strength is above 200 MPa when 5% and 7% CED are introduced. These MPI films exhibit good mechanical performances. The dielectric constant of PI−10% film can go as low as 3.17. Meanwhile, the relationship between dielectric properties and molecular structure has been demonstrated by Molecular Simulation (MS). PI molecules are separated by low dielectric groups, resulting in a decrease in the dielectric constant. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Bis‐Alkoxide Dysprosium(III) Crown Ether Complexes Exhibit Tunable Air Stability and Record Energy Barrier.
- Author
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Xu, Wen‐Jie, Luo, Qian‐Cheng, Li, Zi‐Han, Zhai, Yuan‐Qi, and Zheng, Yan‐Zhen
- Subjects
- *
ACTIVATION energy , *DYSPROSIUM , *SINGLE molecule magnets , *CROWN ethers , *MAGNETIZATION reversal - Abstract
High‐performance and air‐stable single‐molecule magnets (SMMs) can offer great convenience for the fabrication of information storage devices. However, the controversial requisition of high stability and magnetic axiality is hard to balance for lanthanide‐based SMMs. Here, a family of dysprosium(III) crown ether complexes possessing hexagonal‐bipyramidal (pseudo‐D6h symmetry) local coordination geometry with tunable air stability and effective energy barrier for magnetization reversal (Ueff) are shown. The three complexes share the common formula of [Dy(18‐C‐6)L2][I3] (18‐C‐6 = 1,4,7,10,13,16‐hexaoxacyclooctadecane; L = I, 1; L = OtBu 2 and L = 1‐AdO 3). 1 is highly unstable in the air. 2 can survive in the air for a few minutes, while 3 remains unchanged in the air for more than 1 week. This is roughly in accordance with the percentage of buried volumes of the axial ligands. More strikingly, 2 and 3 show progressive enhancement of Ueff and 3 exhibits a record high Ueff of 2427(19) K, which significantly contributes to the 100 s blocking temperature up to 11 K for Yttrium‐diluted sample, setting a new benchmark for solid‐state air‐stable SMMs. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. Update on chiral recognition mechanisms in separation science.
- Author
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Scriba, Gerhard K. E.
- Subjects
- *
ENANTIOMERS , *NUCLEAR magnetic resonance spectroscopy , *CHIRAL recognition , *MOLECULAR spectroscopy , *CYCLODEXTRINS , *CROWN ethers , *MOLECULAR interactions , *POLYSACCHARIDES - Abstract
The stereospecific analysis of chiral molecules is an important issue in many scientific fields. In separation sciences, this is achieved via the formation of transient diastereomeric complexes between a chiral selector and the selectand enantiomers driven by molecular interactions including electrostatic, ion‐dipole, dipole‐dipole, van der Waals or π‐π interactions as well as hydrogen or halogen bonds depending on the nature of selector and selectand. Nuclear magnetic resonance spectroscopy and molecular modeling methods are currently the most frequently applied techniques to understand the selector‐selectand interactions at a molecular level and to draw conclusions on the chiral separation mechanism. The present short review summarizes some of the recent achievements for the understanding of the chiral recognition of the most important chiral selectors combining separation techniques with molecular modeling and/or spectroscopic techniques dating between 2020 and early 2024. The selectors include polysaccharide derivatives, cyclodextrins, macrocyclic glycopeptides, proteins, donor‐acceptor type selectors, ion‐exchangers, crown ethers, and molecular micelles. The application of chiral ionic liquids and chiral deep eutectic solvents, as well as further selectors, are also briefly addressed. A compilation of all published literature on chiral selectors has not been attempted. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. A New Crown Ether of Mahonia fortunei.
- Author
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Chen, C. Y., Kao, C. L., Kuo, C. E., Li, H. T., and Cheng, M. J.
- Subjects
- *
CROWN ethers , *ISOQUINOLINE alkaloids - Abstract
A new 12-crown 4-ether, 2-nonyl-1,4,7,10-tetraoxacyclododecane (1) was isolated from the leaves of Mahonia fortunei (Berberidaceae). The structure of the new crown ether was elucidated by chemical and physical evidences. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. CrownPhos: A Review of Crown Ether Derivatives Decorated with Phosphorus Donors.
- Author
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Ananthnag, Guddekoppa S.
- Subjects
- *
ETHER derivatives , *CROWN ethers , *HOST-guest chemistry , *PHOSPHORUS , *CYCLIC ethers , *POLYETHERS - Abstract
Crown ethers are cyclic polyethers of varied ring sizes. The ability to bind to cations of specific size and charge is based on the ring size, donor atoms present in the crown cavity, and geometry. The host-guest chemistry of crown ethers is further enriched by the introduction of other donor atoms into the crown cavity. For example, aza-crown ethers are crown ethers wherein one or more oxygen atoms are replaced by nitrogen donors. The replacement of donor atoms appreciably alters the ability of the crown cavity to host guest molecules. Phosphorus donors can be introduced to the crown ethers on the periphery to generate hybrid ligands. In these hybrid "CrownPhos" ligand systems, the crown cavity selectively binds to hard cations and phosphorus donors preferentially bind to soft transition metal centers. The presence of guest cations in the crown ether cavity can alter the steric and electronic properties of the phosphorus donors and thereby modulate catalytic ability. The current review focuses on various synthetic and catalytic aspects of crown ethers, aza-crown ethers, and thia-crown ethers appended with phosphorus donors on the periphery. Crownphos: Crown ethers decorated with tertiary phosphorus donors. The details of syntheses, reactivity, host-guest chemistry, and catalytic activities of functionalized crown ethers with phosphorus donors reported in the literature are discussed in the review. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Supramolecular Aza Crown Ether Modulator for Efficient and Stable Perovskite Solar Cells.
- Author
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Xia Chen, Chunyan Deng, Jihuai Wu, Qi Chen, Yitian Du, Yuan Xu, Ruoshui Li, Lina Tan, Yuelin Wei, Yunfang Huang, and Zhang Lan
- Subjects
- *
CROWN ethers , *SOLAR cells , *PEROVSKITE - Abstract
Molecular modulators have been demonstrated to be an effectual strategy for reducing the defect at the interface and in bulk of perovskite and ameliorating the performance and stability of perovskite solar cells (PSCs). Herein, 1-aza-15-crown 5-ether (A15C5), with a unique nitrogen heterocyclic structure as a molecular modulator is introduced at the interface between perovskite layer and hole transport layer of PSCs. Multiple supramolecular synergistic interaction between A15C5 and perovskite dramatically suppress and passivate defects, resulting in a 38% decrease in electron trap-state density in perovskite. The formation of two-dimensional/th3D perovskite heterojunctions induced by planar A15C5 releases residual strain of perovskite film, optimizes the match of energy level array and boosts the stability of devices. Consequently, A15C5-modulated PSC achieves an impressing efficiency of 24.13% along with excellent humidity, light and thermal stability. This work provides a typical strategy to utilize supramolecular crown ether in PSCs. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. A Platform Approach to Cleavable Macrocycles for the Controlled Disassembly of Mechanically Caged Molecules.
- Author
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Saady, Abed, Malcolm, Georgia K., Fitzpatrick, Matthew P., Pairault, Noel, Tizzard, Graham J., Mohammed, Soran, Tavassoli, Ali, and Goldup, Stephen M.
- Subjects
- *
MOLECULES , *CROWN ethers , *PEPTIDES , *OLIGONUCLEOTIDES - Abstract
Inspired by interlocked oligonucleotides, peptides and knotted proteins, synthetic systems where a macrocycle cages a bioactive species that is "switched on" by breaking the mechanical bond have been reported. However, to date, each example uses a bespoke chemical design. Here we present a platform approach to mechanically caged structures wherein a single macrocycle precursor is diversified at a late stage to include a range of trigger units that control ring opening in response to enzymatic, chemical, or photochemical stimuli. We also demonstrate that our approach is applicable to other classes of macrocycles suitable for rotaxane and catenane formation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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