2,025 results
Search Results
2. Photo‐Controllable Ultralong Room‐Temperature Phosphorescence: State of the Art.
- Author
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Nie, Fei and Yan, Dongpeng
- Subjects
PHOTOCHROMIC materials ,PHOSPHORESCENCE ,ELECTRONIC paper ,INORGANIC polymers ,DIARYLETHENE ,SMALL molecules ,OPTOELECTRONICS ,MOIETIES (Chemistry) - Abstract
In this concept, we showcase the upsurge in the studies of dynamic ultralong room‐temperature phosphorescence (RTP) materials containing inorganic and/or organic components as versatile photo‐responsive platforms. The goal is to provide a comprehensive analysis of photo‐controllable RTP, and meanwhile delve into the underlying RTP properties of various classes of photochromic materials including metal‐organic complexes, organic‐inorganic co‐crystals, purely organic small molecules and organic polymers. In particular, the design principles governing the integration of the photochromic and RTP moieties within a single material system, and the tuning of dynamic RTP in response to light are emphasized. As such, this concept sheds light on the challenges and opportunities of using these tunable RTP materials for potential applications in optoelectronics, particularly highlighting their use of reversible information encryption, erasable light printing and rewritable smart paper. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Cd/Cd(OH)2 Nanosheets Enhancing the Electrocatalytic Activity of CO2 Reduction to CO.
- Author
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Jia, Xiaoyan, Qi, Kongsheng, Yang, Jie, Fan, Zixi, Hua, Zhixin, Wan, Xiaoqi, Zhao, Yuhua, Mao, Yidan, and Yang, Dexin
- Subjects
NANOSTRUCTURED materials ,ELECTROLYTIC reduction ,GREENHOUSE effect ,CARBON dioxide ,CARBON paper ,ENERGY shortages ,ELECTRIC charge - Abstract
Electric‐driven conversion of carbon dioxide (CO2) to carbon monoxide (CO) under mild reaction conditions offers a promising approach to mitigate the greenhouse effect and the energy crisis. Surface engineering is believed to be one of the prospective methods for enhancing the electrocatalytic activity of CO2 reduction. Herein, hydroxyl (OH) groups were successfully introduced to cadmium nanosheets to form cadmium and cadmium hydroxide nanocomposites (i. e. Cd/Cd(OH)2 nanosheets) via a facile two‐step method. The as‐prepared Cd/Cd(OH)2/CP (CP indicates carbon paper) electrode displays excellent electrocatalytic activity for CO2 reduction to produce CO. The Faradaic efficiency of CO reaches 98.3 % and the current density achieves 23.8 mA cm−2 at −2.0 V vs. Ag/Ag+ in a CO2‐saturated 30 wt% 1‐butyl‐3‐methylimidazole hexafluorophosphate ([Bmim]PF6)‐65 wt% acetonitrile (CH3CN)‐5 wt% water (H2O) electrolyte. And the CO partial current density can reach up to 71.6 mA cm−2 with the CO Faradaic efficiency of more than 85 % at −2.3 V vs. Ag/Ag+, which stands out against Cd/CP, Cd(OH)2/CP, and Cd/CdO/CP electrodes. The excellent electrocatalytic performance of the Cd/Cd(OH)2/CP electrode can be attributed to its unique structural properties, suitable OH groups, perfect interaction with electrolyte, abundant active sites and fast electron transfer rate. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. Room Temperature Hydroxyl Group‐Assisted Preparation of Hydrophobicity‐Adjustable Metal‐Organic Framework UiO‐66 Composites: Towards Continuous Oil Collection and Emulsion Separation.
- Author
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Xiang, Wenlong, Liu, Huiwen, Zhu, Jiabin, Gong, Hongyang, and Cao, Qizheng
- Subjects
METAL-organic frameworks ,SUPERHYDROPHOBIC surfaces ,EMULSIONS ,PETROLEUM ,CONTACT angle ,FILTER paper - Abstract
Developing a straightforward and effective hydrophobic modification for metal−organic frameworks (MOFs) under mild conditions is meaningful for MOF applications. Here, a post‐synthetic modification approach assisted with metal hydroxyl groups at room temperature is reported to induce hydrophobicity in the hydrophilic UiO‐66. The bonding between Zr−OH in UiO‐66 and n‐tetradecylphosphonic acid (TDPA) is the vital force for the modifier TDPA. Superhydrophobic and superoleophilic composites were constructed for efficient oil‐water separation by coating TDPA‐modified UiO‐66 (P‐UiO‐66) on commercial melamine sponges (MS) and filter papers (FP) with water contact angles of 153.2° and 155.6°, respectively. The P‐UiO‐66/MS composite could quickly and selectively absorb oily liquids up to 43 times its weight from water. The P‐UiO‐66/MS achieved continuous oil collection with high separation efficiencies (≥99.4 %). In addition, P‐UiO‐66/FP and P‐UiO‐66/MS showed high separation efficiencies for water‐in‐oil emulsions (≥98.5 %) and oil‐in‐water emulsions, respectively, with high resistance to low/high temperatures and acid/base conditions. The metal hydroxyl group‐assisted post‐synthetic modification strategy offers a facile and broad way to prepare hydrophobic MOFs for promising applications in environmental fields. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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5. Disulphide Cross‐Linked Ultrashort Peptide Hydrogelator for Water Remediation.
- Author
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Kanti Das, Basab, Samanta, Raju, Ahmed, Sahnawaz, and Pramanik, Bapan
- Subjects
PEPTIDES ,AMINO acid sequence ,WATER pollution ,BUFFER solutions ,FILTER paper - Abstract
A single amino acid in a peptide sequence can play an important role to tune the self‐assembly and hydrogelation behaviour. Here, a C‐terminal cysteine‐containing ultrashort peptide hydrogelator forms hydrogel through non‐covalent and covalent interactions. Interestingly, the hydrogel is insoluble in water and buffer solutions at different pH values (1‐13) and is thixotropic and injectable. In recent years, removing dyes from contaminated water has become a significant concern because of the shortage of freshwater resources. Therefore, the adsorption of dyes through a reliable, straightforward, nontoxic, cheap, and environmentally friendly adsorbent has become a popular topic. Hence, the hydrogelator was exploited to remove organic dyes from wastewater, harnessing its applicability in the gel phase and solid supports (filter paper and cotton). [ABSTRACT FROM AUTHOR]
- Published
- 2023
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6. Electrochemically Assisted Cycloaddition of Carbon Dioxide to Styrene Oxide on Copper/Carbon Hybrid Electrodes: Active Species and Reaction Mechanism.
- Author
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Li, Wenze, Qi, Ke, Lu, Xingyu, Qi, Yujie, Zhang, Jialong, Zhang, Bingsen, and Qi, Wei
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STYRENE oxide ,CARBON dioxide ,RING formation (Chemistry) ,CARBON electrodes ,CARBON paper ,SURFACE charges - Abstract
A novel electrochemically assisted cycloaddition process is proposed, in which highly efficient coupling of CO2 with styrene oxide (SO) can be achieved to form styrene carbonate (SC) as a high‐value‐added product. A series of Cu catalysts with different morphologies and chemical states were fabricated on carbon paper (CP) by using in‐situ electrodeposition, and the sample with nano‐dendrimer structure was found to exhibit a relatively high activity of 74.8 % SC yield with 92.7 % SO conversion under gentle reaction conditions, thus showing its potential for practical applications. The relatively high electrochemically active surface area and charge transfer ability of dendrimer‐like Cu benefited the electrochemical reaction. In particular, the Cu2+ species that were formed in situ during the reaction played a vital role in enhancing the activity and selectivity of the proposed Cu/CP hybrid catalyst. Cu2+ atoms served as active sites that can not only electrochemically activate CO2 but also facilitate the ring opening of SO. Mechanistic analysis suggested that the reaction followed electrochemical and liquid‐phase heterogeneous paths, which provide a new green and sustainable route for efficient utilization of CO2 resources for fine chemical electrosynthesis. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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7. Luminescent Organic‐Inorganic Hybrid Metal Halides: An Emerging Class of Stimuli‐Responsive Materials.
- Author
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Wang, Zeping and Huang, Xiaoying
- Subjects
- *
METAL halides , *ELECTRONIC paper , *ORGANIC conductors , *ORGANOMETALLIC compounds - Abstract
Luminescent organic‐inorganic metal halides (OIMHs) are well known as a new materials family in recent years. Novel materials and applications of luminescent OIMHs have been explored by changing either the organic component or the metal halide species. Thereinto, the stimuli‐responsive (SR) phenomena in OIMHs have drawn much attention recently, for not only their attractive application potential but also the helpfulness in understanding the stability of OIMHs to the external environment. Herein, the luminescent OIMHs that are sensitive to external stimuli including contact, pressure, mechanical grinding, light, heat, and gas molecules, are reviewed, with an emphasis on analyses of the structural change during the SR process. The applications of SR luminescent OIMHs in widespread fields, including gas sensing, information encryption, and rewritable luminescent paper are summarized. Finally, the challenges that deserve to be further explored in this research field are discussed, which provides certain guidance for the future study of SR luminescent OIMHs. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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8. Porous Anionic Co(II) Metal‐Organic Framework, with a High Density of Amino Groups, as a Superior Luminescent Sensor for Turn‐on Al(III) Detection.
- Author
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Chand, Santanu, Verma, Gaurav, Pal, Arun, Pal, Shyam Chand, Ma, Shengqian, and Das, Madhab C.
- Subjects
AMINO group ,METAL-organic frameworks ,DETECTORS ,FREE groups ,FILTER paper ,ION channels - Abstract
Accumulation of high concentrations of Al(III) in body has a direct impact on health and therefore, the trace detection of Al(III) has been a matter for substantial concern. An anionic metal organic framework ({[Me2NH2]0.5[Co(DATRz)0.5(NH2BDC)] ⋅ xG}n; 1; HDATRz=3,5‐diamino‐1,2,4‐triazole, H2NH2‐BDC=2‐amino‐1,4‐benzenedicarboxylic acid, G=guest molecule) composed of two types of secondary building units (SBU) and channels of varying sizes was synthesized by employing a rational design mixed ligand synthesis approach. Free −NH2 groups on both the ligands are immobilized onto the pore surface of the MOF which acts as a superior luminescent sensor for turn‐on Al(III) detection. Furthermore, the large channels could allow the counter‐ions to pass through and get exchanged to selectively detect Al(III) in presence of other seventeen metal ions with magnificent luminescence enhancement. The observed limit of detection is as low as 17.5 ppb, which is the lowest among the MOF‐based sensors achieved so far. To make this detection approach simple, portable and economic, we demonstrate MOF filter paper test for real time naked eye observation. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
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9. Sustainable and Robust Graphene Cellulose Paper Decorated with Lithiophilic Au Nanoparticles to Enable Dendrite‐free and High‐Power Lithium Metal Anode.
- Author
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Diao, Wan‐Yue, Xie, Dan, Li, Yan‐Fei, Jiang, Ru, Tao, Fang‐Yu, Sun, Hai‐Zhu, Wu, Xing‐Long, Zhang, Xiao‐Ying, and Zhang, Jing‐Ping
- Subjects
GOLD nanoparticles ,CELLULOSE ,METALS ,LITHIUM cell electrodes ,GRAPHENE ,CELLULOSE nanocrystals ,HYDROGEN evolution reactions ,GRAPHITE oxide - Abstract
Lithium metal anodes (LMAs) with high energy density have recently captured increasing attention for development of next‐generation batteries. However, practical viability of LMAs is hindered by the uncontrolled Li dendrite growth and infinite dimension change. Even though constructing 3D conductive skeleton has been regarded as a reliable strategy to prepare stable and low volume stress LMAs, engineering the renewable and lithiophilic conductive scaffold is still a challenge. Herein, a robust conductive scaffold derived from renewable cellulose paper, which is coated with reduced graphene oxide and decorated with lithiophilic Au nanoparticles, is engineered for LMAs. The graphene cellulose fibres with high surface area can reduce the local current density, while the well‐dispersed Au nanoparticles can serve as lithiophilic nanoseeds to lower the nucleation overpotential of Li plating. The coupled relationship can guarantee uniform Li nucleation and unique spherical Li growth into 3D carbon matrix. Moreover, the natural cellulose paper possesses outstanding mechanical strength to tolerate the volume stress. In virtue of the modulated deposition behaviour and near‐zero volume change, the hybrid LMAs can achieve reversible Li plating/stripping even at an ultrahigh current density of 10 mA cm−2 as evidenced by high Coulombic efficiency (97.2 % after 60 cycles) and ultralong lifespan (1000 cycles) together with ultralow overpotential (25 mV). Therefore, this strategy sheds light on a scalable approach to multiscale design versatile Li host, promising highly stable Li metal batteries to be feasible and practical. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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10. Cover Feature: Diiminium Nucleophile Adducts Are Stable and Convenient Strong Lewis Acids (Chem. Eur. J. 58/2023).
- Author
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Bormann, Niklas, Ward, Jas S., Bergmann, Ann Kathrin, Wenz, Paula, Rissanen, Kari, Gong, Yiwei, Hatz, Wolf‐Benedikt, Burbaum, Alexander, and Mulks, Florian F.
- Subjects
LEWIS acids ,ELECTRONIC paper ,DEHYDRATION reactions ,ELECTRIC potential - Abstract
Keywords: amides; carbodications; carbocations; cations; Lewis acids EN amides carbodications carbocations cations Lewis acids 1 1 1 10/24/23 20231018 NES 231018 B Dicationic diiminium pyridine adducts b distinctively concentrate their positive charges at the diiminium carbon atom, a characteristic vividly portrayed in their molecular electrostatic potential. Amides, carbodications, carbocations, cations, Lewis acids. [Extracted from the article]
- Published
- 2023
- Full Text
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11. Thioxanthylium Cations: Highly Reversible Hydrochromic Mate‐rials with Tunable Color and Moisture Sensitivity.
- Author
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Chua, Ming Hui, Soo, Xiang Yun Debbie, Goh, Wei Peng, Png, Zhuang Mao, Zhu, Qiang, and Xu, Jianwei
- Subjects
MOISTURE ,CATIONS ,TRIFLUOROACETIC acid ,COLOR ,HUMIDITY - Abstract
Hydrochromic materials, which change color in response to moisture, are highly sought‐after due to some unique applications such as moisture detection, humidity monitoring, anti‐counterfeiting, and sweat‐pore mapping. We herein report a new thioxanthene‐9‐ols/thioxanthylium cations hydrochromic system. The hydrochromic thioxanthylium cations can be generated/regenerated by exposing a chemically stable thioxanthene‐9‐ol to trifluoroacetic acid (TFA). The intensely colored thioxanthylium cations can be chemically reverted to the colorless thioxanthene‐9‐ol. Interestingly, the conversion between thioxanthene‐9‐ol and its cation species was found to be highly reversible in most cases (up to 50 activation‐deactivation cycles). The color and moisture‐sensitivity of thioxanthylium cations were also validated to be tunable via functionalization of the thioxanthene core with different aliphatic and aromatic groups at its 9 or 2,7‐positions. Finally, paper probes were prepared using solution‐immersion and inkjet‐printing techniques to demonstrate the system's potential applications in humidity sensing and anti‐counterfeiting [ABSTRACT FROM AUTHOR]
- Published
- 2022
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12. Developing Flexible Quinacridone‐Derivatives‐Based Photothermal Evaporaters for Solar Steam and Thermoelectric Power Generation.
- Author
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Shen, Meihua, Zhao, Xinpeng, Han, Lu, Jin, Nanxi, Liu, Song, Jia, Tao, Chen, Zhijun, and Zhao, Xiuhua
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THERMOELECTRIC power ,THERMOELECTRIC apparatus & appliances ,SOLAR heating ,SOLAR stills ,WATER supply ,SOLAR thermal energy ,THERMOELECTRIC generators - Abstract
Solar‐driven interfacial vaporization by localizing solar‐thermal energy conversion to the air−water interface has attracted tremendous attention. In the process of converting solar energy into heat energy, photothermal materials play an essential role. Herein, a flexible solar‐thermal material di‐cyan substituted 5,12‐dibutylquinacridone (DCN−4CQA)@Paper was developed by coating photothermal quinacridone derivatives on the cellulose paper. The DCN−4CQA@Paper combines desired chemical and physical properties, broadband light‐absorbing, and shape‐conforming abilities that render efficient photothermic vaporization. Notably, synergetic coupling of solar‐steam and solar‐electricity technologies by integrating DCN−4CQA@Paper and the thermoelectric devices is realized without trade‐offs, highlighting the practical consideration toward more impactful solar heat exploitation. Such solar distillation and low‐grade heat‐to‐electricity generation functions can provide potential opportunities for fresh water and electricity supply in off‐grid or remote areas. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
13. Fenton‐Like Reaction: Recent Advances and New Trends.
- Author
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Xiao, Jiaying, Guo, Sufang, Wang, Dong, and An, Qi
- Subjects
HABER-Weiss reaction ,HYDROGEN peroxide ,SOIL degradation ,IRON ions ,OIL spills ,SOIL pollution - Abstract
The Fenton reaction refers to the reaction in which ferrous ions (Fe2+) produce hydroxyl radicals and other reactive oxidizing substances by decomposing hydrogen peroxide (H2O2). This paper reviews the mechanism, application system, and materials employed in the Fenton reaction including conventional homogeneous and non‐homogeneous Fenton reactions as well as photo‐, electrically‐, ultrasonically‐, and piezoelectrically‐triggered Fenton reactions, and summarizes the applications in the degradation of soil oil pollutions, landfill leachate, textile wastewater, and antibiotics from a practical point of view. The mineralization paths of typical pollutant are elucidated with relevant case studies. The paper concludes with a summary and outlook of the further development of Fenton‐like reactions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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14. The Utilization of Metal‐Organic Frameworks and Their Derivatives Composite in Supercapacitor Electrodes.
- Author
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Liu, Qianwen, Li, Ruidong, Li, Jie, Zheng, Bingyue, Song, Shuxin, Chen, Lihua, Li, Tingxi, and Ma, Yong
- Abstract
Up to now, the mainstream adoption of renewable energy has brought about substantial transformations in the electricity and energy sector. This shift has garnered considerable attention within the scientific community. Supercapacitors, known for their exceptional performance metrics like good charge/discharge capability, strong power density, as well as extended cycle longevity, have gained widespread traction across various sectors, including transportation and aviation. Metal‐organic frameworks (MOFs) with unique traits including adaptable structure, highly customizable synthetic methods, and high specific surface area, have emerged as strong candidates for electrode materials. For enhancing the performance, MOFs are commonly compounded with other conducting materials to increase capacitance. This paper provides a detailed analysis of various common preparation strategies and characteristics of MOFs. It summarizes the recent application of MOFs and their derivatives as supercapacitor electrodes alongside other carbon materials, metal compounds, and conductive polymers. Additionally, the challenges encountered by MOFs in the realm of supercapacitor applications are thoroughly discussed. Compared to previous reviews, the content of this paper is more comprehensive, offering readers a deeper understanding of the diverse applications of MOFs. Furthermore, it provides valuable suggestions and guidance for future progress and development in the field of MOFs. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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15. Structural Self‐Assembly and Applications of Metal–Organic Molecular Containers with Flexible Backbones.
- Author
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Yang, Lu, Huang, Xiaoxue, Wang, Suna, Zhang, Daopeng, and Zhou, Zhen
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FLEXIBLE packaging ,SUPRAMOLECULAR chemistry ,MOLECULAR recognition ,CHEMICAL properties ,FUNCTIONAL groups ,SPINE - Abstract
Supramolecular chemistry has become an interdisciplinary discipline of chemistry, physics, and biology. As a huge subunit of supramolecular compounds, the functional metal–organic supramolecular systems with well‐defined cavities which are able to accommodate size‐suitable guests via benign host‐guest behavior, have been known as "metal–organic molecular containers" (MOMCs) and attracted much attentions for their rich chemical properties and wide potential applications in molecular recognition, catalysis, bio‐medical and other fields. In particular, the MOMCs with flexible backbones exhibit a unique feature both in the aspect of structural construction and applications, due to the free rotation and self‐adaptively of the specific functional groups in the skeletons. In this paper, we review several selected examples of the coordination‐driven metal–organic supramolecular systems from the aspects of self‐assembly construction to the various applications. The self‐assembly strategies, especially the different choice of organic ligands with flexible backbones during the construction, leading to quite diverse configurations compared to the rigid ligands, have been also discussed to show a different perspective of metal–organic system construction. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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16. A Foldable Aqueous Zn‐Ion Battery with Gear‐Structured Composite as Freestanding Cathode.
- Author
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Liu, Jinyun, Zhu, Yajun, Han, Tianli, Zhang, Huigang, Hu, Chaoquan, and Niu, Junjie
- Subjects
SELF-healing materials ,IONIC conductivity ,POLYVINYL alcohol ,CATHODES ,ELECTRONIC equipment ,SURFACE diffusion ,GLYCERIN - Abstract
A foldable battery with high flexibility provides great potential in various wearable electronic devices for health and fitness tracking, chronic disease management, performance monitoring, navigation tracking, and portable gears for soldiers. We report a highly flexible, self‐healing Zn‐ion battery with a free‐standing cathode that is composed of a 3D gear‐like NH4V4O10@C composite on carbon paper. The battery retained a capacity of up to 102.4 mAh g−1 even after being folded 60 times with a high angle of 180°. An aqueous hydrogel consisting polyvinyl alcohol, glycerin and Zn(CF3SO3)2 was used as electrolyte, which showed as high as 580 % tensile strain under a loading weight of 78 N. The battery exhibited a better capacity retention of over 100 mAh g−1 and Coulombic efficiency of over 99.8 % after cutting and twisting to 90°, thereby indicating a great self‐healing performance. The gear‐like geometry greatly improved the volume accommodation due to the increased interval space between the blades and the outward configuration. Meanwhile the Zn2+ ionic conductivity was improved by rapid re‐binding of many existing hydroxy groups from the electrolyte and the enhanced contact surface area and diffusion route from the cathode material. The highly flexible, safe aqueous Zn‐ion battery opens a practical way to power various carry‐on electronics under mechanical agitation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
17. Macroscopic Polarization Change of Mononuclear Valence Tautomeric Cobalt Complexes Through the Use of Enantiopure Ligand.
- Author
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Cheng, Feng, Wu, Shuqi, Zheng, Wenwei, Su, Shengqun, Nakanishi, Takumi, Xu, Wenhuang, Sadhukhan, Pritam, Sejima, Hibiki, Ikenaga, Shimon, Yamamoto, Kaoru, Gao, Kaige, Kanegawa, Shinji, and Sato, Osamu
- Subjects
VALENCE fluctuations ,SPACE groups ,CHARGE exchange ,COBALT ,COMPUTER storage devices ,ENANTIOMERS - Abstract
The crystallization of a complex having electron transfer properties in a polar space group can induce the polarization switching of a crystal in a specific direction, which is attractive for the development of sensors, memory devices, and capacitors. Unfortunately, the probability of crystallization in a polar space group is usually low. Noticing that enantiopure compounds crystallize in Sohncke space groups, this paper reports a strategy for the molecular design of non‐ferroelectric polarization switching crystals based on the use of intramolecular electron transfer and chirality. In addition, this paper describes the synthesis of a mononuclear valence tautomeric (VT) cobalt complex bearing an enantiopure ligand. The introduction of enantiomer enables the crystallization of the complex in the polar space group (P21). The polarization of the crystals along the b‐axis direction is not canceled out and the VT transition is accompanied by a change in the macroscopic polarization of the polar crystal. Polarization switching via electron transfer is realized at around room temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
18. Chalcogen Bonding (ChB) as a Robust Supramolecular Recognition Motif of Benzisothiazolinone Antibacterials.
- Author
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Pizzi, Andrea, Daolio, Andrea, Beccaria, Roberta, Demitri, Nicola, Viani, Fiorenza, and Resnati, Giuseppe
- Subjects
ANTIFOULING paint ,BINDING sites ,GRAM-negative bacteria ,ANTIBACTERIAL agents ,CHEMICAL reactions ,COVALENT bonds - Abstract
1,2‐benzisothiazol‐3(2H)‐one derivatives are highly active against a broad spectrum of fungi as well as Gram positive and Gram negative bacteria. For this reason they are extensively used, for example, as additives in detergents, leather products, paper coatings, and antifouling paintings. In this paper experimental findings are reported proving that the sulfur atom of benzisothiazolinones have a remarkable tendency to form short and directional chalcogen bondings on the extension of the covalent N−S bond and, to a lesser extent, of the C−S bond. Analyses of the Cambridge Structural Database confirm the interaction as a primary recognition motif of these systems. The electrophilicity of sulfur is crucial in the chemical reactions initiating the cascade of events resulting in the biopharmacological activities of benzisothiazolinones. The reported results suggest that the electrophility of sulfur may play a role also at earlier stages than the reactive ones, namely it may pin the compounds at the active site of target enzymes via chalcogen bondings that preorganize the system in the conformation required for the bonds formation/cleavage determining the biopharmacological activity [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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19. Emergent Properties in Chemistry ‐ Relating Molecular Properties to Bulk Behavior.
- Author
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Sieroka, Norman, Lossau, Tammo, and Neudecker, Tim
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QUANTUM phase transitions ,CHEMICAL properties - Abstract
Certain properties of an object only emerge when a sufficient number of those objects are present in a definite arrangement. For example, one or two water molecules cannot said to be in a liquid state, but a drop of water can be. This concept of emergence has been studied extensively, but only occasionally discussed explicitly in the context of chemistry. In this paper, we aim to show the fruitfulness of the concept of emergence for chemical inquiry by considering four case studies of emergent chemical properties, i. e., the liquidity and freezing of water, structural properties of crystals, thermodynamical phase transitions and quantum mechanical phenomena. We show that some of these properties emerge gradually, some at discrete points, and some should be taken to emerge only when the number of constituents tends to infinity. We argue that studying the way in which chemical properties emerge presents a useful avenue for research that promises greater insight into the nature of those properties. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
20. Palladium‐Catalyzed Enantioselective [4+2] Cycloaddition of 4‐Vinylbenzodioxinones with Barbiturate‐Derived Alkenes: Con‐struction of Chiral Spirobarbiturate−Chromanes.
- Author
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Tang, Yi, Huang, Mingxia, Ding, Siyuan, Liu, Xinyao, Huyang, Xiaochun, Wang, Bo, and Guo, Hongchao
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ALKENES ,RING formation (Chemistry) ,PALLADIUM ,CATALYSIS - Abstract
In this paper, Pd‐catalyzed [4+2] decarboxylative cycloaddition of 4‐vinylbenzodioxinones with barbiturate‐derived alkenes has been developed, leading to various spirobarbiturate−chromane derivatives in high yields with excellent diastereo‐ and enantioselectivities. The scale‐up reaction and further derivation of the product were demonstrated. A plausible reaction mechanism was also proposed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
21. Recent Advances of Flexible MXene and its Composites for Supercapacitors.
- Author
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Jiang, Shiben, Lu, Linghong, and Song, Yan
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ELECTRIC conductivity ,SURFACE chemistry - Abstract
MXenes have unique properties such as high electrical conductivity, excellent mechanical properties, rich surface chemistry, and convenient processability. These characteristics make them ideal for producing flexible materials with tunable microstructures. This paper reviews the laboratory research progress of flexible MXene and its composite materials for supercapacitors. And introduces the general synthesis method of MXene, as well as the preparation and properties of flexible MXene. By analyzing the current research status, the electrochemical reaction mechanism of MXene was explained from the perspectives of electrolyte and surface terminating groups. This review particularly emphasizes the composite methods of freestanding flexible MXene composite materials. The review points out that the biggest problem with flexible MXene electrodes is severe self‐stacking, which reduces the number of chemically active sites, weakens ion accessibility, and ultimately lowers electrochemical performance. Therefore, it is necessary to composite MXene with other electrode materials and design a good microstructure. This review affirms the enormous potential of flexible MXene and its composite materials in the field of supercapacitors. In addition, the challenges and possible improvements faced by MXene based materials in practical applications were also discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
22. Synthesis of [1]Benzothieno[3,2‐b][1]benzothiophenes through Iodine‐Mediated Sulfur Insertion Reaction.
- Author
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Ito, Kazuki, Nakamura, Kohei, and Yoshida, Kazuhiro
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ORGANIC field-effect transistors ,SULFUR ,THIOPHENES - Abstract
[1]Benzothieno[3,2‐b][1]benzothiophenes (BTBTs) are important molecules that have been extensively studied as high‐performance organic field‐effect transistors (OFETs). Therefore, it is important to develop a simple synthetic method for these molecules. In this paper, a synthetic method to obtain the BTBTs from 2‐arylbenzo[b]thiophenes and elemental sulfur, in which two C−S bonds are formed at once, is described. In this method, molecular iodine plays a very important role as an additive. The role of iodine is discussed in the presumed reaction pathways. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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23. Versatile Polymerization‐Induced Emission Polymers from Barbier Polymerization of Cinnamic Esters with Tunable Emission.
- Author
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Sun, Xiao‐Li, Chen, Yu‐Jiao, Cai, Hua‐Wen, Gu, Xi‐Yao, Li, De‐Shan, Wu, Liang‐Tao, and Wan, Wen‐Ming
- Subjects
HYDROXYCINNAMIC acids ,ESTERS ,POLYMERIZATION ,POLYMERS ,CHEMICAL structure ,EXPLOSIVES - Abstract
Cinnamic ester is a common and abundant chemical substance, which can be extracted from natural plants. Compared with traditional esters, cinnamic ester contains α,β‐unsaturated carbonyl structure with multiple reactive sites, resulting in more abundant reactivities and chemical structures. Here, a versatile polymerization‐induced emission (PIE) is successfully demonstrated through Barbier polymerization of cinnamic ester. Attributed to its abundant reactivities of α,β‐unsaturated carbonyl structure, Barbier polymerization of cinnamic esters with different organodihalides gives polyalcohol and polyketone via 1,2‐addition and 1,4‐addition, respectively, which is also confirmed by small molecular model reactions. Meanwhile, these organodihalides dependant polyalcohol and polyketone exhibit different non‐traditional intrinsic luminescence (NTIL) from aggregation‐induced emission (AIE) type to aggregation‐caused quenching (ACQ) type, where novel PIE luminogens (PIEgens) are revealed. Further potential applications in explosive detection are carried out, where it achieves TNT detection sensitivity at ppm level in solution and ng level on the test paper. This work therefore expands the structure and functionality libraries of monomer, polymer and NTIL, which might cause inspirations to different fields including polymer chemistry, NTIL, AIE and PIE. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. Plasma Technology for Advanced Electrochemical Energy Storage.
- Author
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Liang, Xinqi, Liu, Ping, Qiu, Zhong, Shen, Shenghui, Cao, Feng, Zhang, Yongqi, Chen, Minghua, He, Xinping, Xia, Yang, Wang, Chen, Wan, Wangjun, Zhang, Jun, Huang, Hui, Gan, Yongping, Xia, Xinhui, and Zhang, Wenkui
- Subjects
LITHIUM-air batteries ,ENERGY storage ,LITHIUM sulfur batteries ,CARBON offsetting ,RADICALS (Chemistry) ,LITHIUM-ion batteries - Abstract
"Carbon Peak and Carbon Neutrality" is an important strategic goal for the sustainable development of human society. Typically, a key means to achieve these goals is through electrochemical energy storage technologies and materials. In this context, the rational synthesis and modification of battery materials through new technologies play critical roles. Plasma technology, based on the principles of free radical chemistry, is considered a promising alternative for the construction of advanced battery materials due to its inherent advantages such as superior versatility, high reactivity, excellent conformal properties, low consumption and environmental friendliness. In this perspective paper, we discuss the working principle of plasma and its applied research on battery materials based on plasma conversion, deposition, etching, doping, etc. Furthermore, the new application directions of multiphase plasma associated with solid, liquid and gas sources are proposed and their application examples for batteries (e. g. lithium‐ion batteries, lithium‐sulfur batteries, zinc‐air batteries) are given. Finally, the current challenges and future development trends of plasma technology are briefly summarized to provide guidance for the next generation of energy technologies. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
25. Charge‐Assisted Ionic Hydrogen‐Bonded Organic Frameworks: Designable and Stabilized Multifunctional Materials.
- Author
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Chen, Xu‐Yong, Cao, Li‐Hui, Bai, Xiang‐Tian, and Cao, Xiao‐Jie
- Subjects
IONIC structure ,GAS absorption & adsorption ,HYDROGEN as fuel ,CRYSTAL structure ,SEPARATION of gases - Abstract
Hydrogen‐bonded organic frameworks (HOFs) are a class of crystalline framework materials assembled by hydrogen bonds. HOFs have the advantages of high crystallinity, mild reaction conditions, good solution processability, and reproducibility. Coupled with the reversibility and flexibility of hydrogen bonds, HOFs can be assembled into a wide diversity of crystalline structures. Since the bonding energy of hydrogen bonds is lower than that of ligand and covalent bonds, the framework of HOFs is prone to collapse after desolventisation and the stability is not high, which limits the development and application of HOFs. In recent years, numerous stable and functional HOFs have been developed by π–π stacking, highly interpenetrated networks, charge‐assisted, ligand‐bond‐assisted, molecular weaving, and covalent cross‐linking. Charge‐assisted ionic HOFs introduce electrostatic attraction into HOFs to improve stability while enriching structural diversity and functionality. In this paper, we review the development, the principles of rational design and assembly of charge‐assisted ionic HOFs, and introduces the different building block construction modes of charge‐assisted ionic HOFs. Highlight the applications of charge‐assisted ionic HOFs in gas adsorption and separation, proton conduction, biological applications, etc., and prospects for the diverse design of charge‐assisted ionic HOFs structures and multifunctional applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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26. Controlling Cyclic Dienamine Reactivity in Radical tert‐Alkylation for Molecular Diversity to Synthesize Multicyclic Compounds Possessing a Quaternary Carbon.
- Author
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Kusano, Shinjiro and Nishikata, Takashi
- Subjects
RADICALS (Chemistry) ,ORGANIC synthesis ,ALKYL compounds ,CARBON ,ALKYLATION ,ENAMINES - Abstract
Synthesis of diverse sterically congested molecules from a single important intermediate is one of the ideal synthetic strategies in organic synthesis. In this paper, we found that γ‐oxoalkyl substituted cyclohexenone derivatives (OAC) possessing a quaternary carbon are a useful key intermediate to derive both congested fused [5,6] rings and spirocycles. For this purpose, we have established an efficient synthetic method to obtain OAC by tertiary alkylation of β‐methylcyclohexenone derivatives using α‐bromocarbonyl compounds as a tertiary alkyl source. The key to the success of this reaction is controlling the reactivity of the dienamine intermediate. While there have been many reports on enamine reactions, dienamine reactions have not been well studied. Herein, we report controlling reactivity of dienamines and molecular diversification from OAC. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. One‐Step Photochemical Preparation of CdS/Poly(MMA‐co‐MAA) Composite with Enhanced Photocatalytic Activity.
- Author
-
Huang, Zhenxun, Ma, Qingrong, and Sun, Fengqiang
- Subjects
PHOTOCATALYSTS ,METHYL methacrylate ,METHACRYLIC acid ,ENVIRONMENTAL chemistry ,PHOTODEGRADATION ,SILVER phosphates - Abstract
This paper presents a one‐step photochemical method for the preparation of CdS/Poly(MMA‐co‐MAA) composite photocatalyst, based on the concept of simultaneous photocatalytic polymerization of organic monomers during UV‐light induced formation of CdS. The preparation is carried out in an aqueous solution of Na2S2O3, CdSO4, methyl methacrylate (MMA) and methacrylic acid (MAA), under a UV lamp. The continuously formed CdS particles with photocatalytic activity act the role of initiator to directly initiate the copolymerization of MMA and MAA, resulting in the in situ formation of the composite and full contact of the CdS particles with the oxygen‐containing groups in the polymer. Taking the photocatalytic degradation of methylene blue as a case study, the composite exhibited significantly higher activity under simulated solar light compared to the pure CdS. By analysis on various data, the enhanced photocatalytic activity is attributed to the enhanced visible light absorption, and especially the high electron‐hole separation efficiency caused by the electrostatic interaction between photogenerated holes and carbonyl oxygen atoms with negatively charged features. Furthermore, the composite displays excellent sunlight activity and recyclability, suggesting its potential for practical applications. Such a one‐step construction strategy relying only on photo‐energy is green, low‐cost and promising in obtaining high‐performance semiconductor/polymer composite photocatalysts. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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28. Celebrating Maurizio Prato's Passion, Talent and Imagination.
- Author
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Bianco, Alberto, Bonchio, Marcella, Bonifazi, Davide, Da Ros, Tatiana, Maggini, Michele, Mateo‐Alonso, Aurelio, and Tecilla, Paolo
- Subjects
YLIDES ,NANOSCIENCE ,MATERIALS science ,PHOTOINDUCED electron transfer ,EDUCATORS ,ORGANIC reaction mechanisms ,CHLOROPLASTS ,ORGANIC chemistry - Abstract
This article introduces a special collection of papers dedicated to Maurizio Prato, a renowned scientist in the field of carbon nanostructures and molecular nanoscience. The collection showcases Prato's team's achievements in integrating complex frontier research with groundbreaking advancements in these fields. Prato's work focuses on designing and synthesizing carbon nanostructures for applications in regenerative medicine and solar energy research. The article highlights Prato's scientific journey, his contributions to sustainable materials, and his impact on shaping functional nano-interfaces through precision chemistry. The Prato lab has made significant contributions to nanotechnology, particularly in the area of functionalized carbon nanotubes (f-CNT). Their research has shown that f-CNT are more biocompatible and easily cleared from the body compared to nonfunctionalized CNT. The lab has applied this knowledge to develop solutions for challenging problems such as healing spinal cord injuries and using water as a solar fuel. Their work in regenerative medicine has shown promising results in repairing severe and irreversible nervous system lesions, while their research in energy conversion has explored the use of f-CNT for solar energy conversion. Maurizio Prato, the leader of the lab, has fostered an interdisciplinary and collaborative environment, encouraging his team to explore diverse research avenues and promoting intellectual freedom. His mentorship and open-mindedness have been instrumental in the lab's success. [Extracted from the article]
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- 2024
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29. Pd‐Catalysed Direct Arylation of Distyrylbenzene: Strong Dual‐state Fluorescence and Electrochromism.
- Author
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Nipate, Atul B. and Rao, M. Rajeswara
- Subjects
FLUORESCENCE yield ,ELECTROCHROMIC effect ,ARYLATION ,FLUORESCENCE ,ARYL group ,CARBAZOLE ,TRIPHENYLAMINE - Abstract
Distyrylbenzenes (DSBs) are well‐known for their strong multicolour fluorescence. Fluorescence tuning of DSB via further functionalization/arylation, on the other hand, is uncommon. This paper reports a Pd‐catalysed direct arylation approach for introducing different aryl groups onto fluorobenzene‐containing DSB moiety (7) in high yields (67–72 %). The versatile methodology allows the substitution of neutral [tolyl (1)], electron‐deficient [p‐formyl benzene (2), p‐acetyl benzene (3), p‐nitrobenzene (4)] and electron‐rich [carbazole (5), triphenylamine (6)] aryl groups. The electron‐deficient aryls render mono‐substitution, while the electron‐rich counterparts promote di‐substitution. The compounds (1–6) show blue, green, and yellow fluorescence in both the solution and solid states; the fluorescence quantum yields reach >98 % and the peak maxima span from 425 to 560 nm. The mono‐carbazole DSB (5) exhibit white light emission (WLM) in polar solvents (acetone, DMF, CH3CN, DMSO and NMP) with very high fluorescence quantum yields (φf) of 60–80 %. For WLM, such high efficiency (φf) is somewhat uncommon. Moreover, visible‐to‐NIR reversible electrochromism is demonstrated by the TPA‐integrated DSB (6). The colour of 6 changes from pristine light yellow to orange, and the absorption maxima shifts from 372 to 1500 nm when a positive potential of 1.0 V vs Ag/Ag+ is applied. Moreover, the system shows high colouration efficiency in the NIR region with fast switching speeds for colouration and decolouration as fast as 0.98 s and 1.05 s. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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30. Nucleophilic Substitution at Phosphorus Centres – Old and Recent Studies and a Final Solution of Mechanistic and Related Stereochemical Problems.
- Author
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Mikołajczyk, Marian
- Subjects
NUCLEOPHILIC substitution reactions ,PHOSPHORUS compounds ,PHOSPHORUS ,CYCLIC compounds ,STEREOCHEMISTRY ,PHOSPHORUS in water ,SUBSTITUTION reactions - Abstract
Among many problems of a fundamental value in the heteroatom chemistry the mechanism and stereochemistry of the nucleophilic substitution reaction at the phosphorus and other heteroatom centres have attracted great attention of phosphorus chemists already in the middle of the last century. This review, which does not have a comprehensive character, summarizes the selected original contributions aimed at solution of the mechanism of SN2−P reaction and its relationship with stereochemistry. The breakthrough in these studies was the Westheimer's concept and his rules which is presented at the beginning of this article. Next, a series of papers is presented where the stereochemistry of the substitution at phosphorus was investigated in cyclic five‐, four‐ and six‐membered ring phosphorus compound. The majority of these reactions have been found to occur with retention of the P‐configuration. In the third part of this account, the selected examples of substitution reactions at phosphorus in acyclic compounds are discussed. As the results of all the investigations discussed did not allow to undoubtedly ascribe the mechanism (SN2 or A−E) to the investigated reactions, in the last part the SN‐P reactions are presented, the mechanism of which has been established by combination of the stereochemical and DFT‐studies. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Dansylated Nitrile N‐Oxide as the Fluorescent Dye Clickable to Unsaturated Bonds without Catalyst.
- Author
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Oku, Yuki, Nakajima, Noriyuki, Hamada, Masahiro, and Koyama, Yasuhito
- Subjects
FLUORESCENT dyes ,THREE-dimensional printing ,NITRILE oxides ,FLUORESCENCE spectroscopy ,NITRILE derivatives ,POLYMER blends ,MOLECULAR spectra - Abstract
Fluorescent polymeric materials have been exploited in the fields of aesthetical purposes, biomedical engineering, and three‐dimensional printing applications. While the fluorescent materials are prepared by the polymerization of fluorescent monomer or the blending a fluorescent dye with common polymer, the covalent immobilization of fluorescent dye onto common polymers is not the practical technique. In this paper, dansylated nitrile N‐oxide (Dansyl‐NO) has been designed and synthesized to be a stable nitrile N‐oxide as the derivative of 2‐hydroxy‐1‐naphthaldehyde. While Dansyl‐NO shows good reactivity to an alkene and an alkyne to give fluorescent Dansyl‐Ene and Dansyl‐Yne, respectively, it hardly reacts to a nitrile. The results indicate that Dansyl‐NO serves as a fluorescent dye clickable to alkenes and alkynes. To know the effects of solvent on the fluorescent properties, the UV‐vis and fluorescence spectra of Dansyl‐Ene are measured in three solvents. Dansyl‐Ene shows fluorescent solvatochromism, which appears to be red‐shifted along with the increase in solvent polarity. Poly(styrene‐co‐butadiene) directly reacts with Dansyl‐NO to give fluorescent modified SB. The emission spectrum of modified SB is blue‐shifted compared with that of Dansyl‐Ene. The blue‐shift could be possibly attributed to the presence of less polar polymer skeleton around the dansyl moieties of modified SB. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. Engineered Nanomaterials for Tumor Immune Microenvironment Modulation in Cancer Immunotherapy.
- Author
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Xing, Hao and Li, Xiaomin
- Abstract
Tumor immunotherapy, represented by immune checkpoint blocking and chimeric antigen receptor (CAR) T cell therapy, has achieved promising results in clinical applications. However, it faces challenges that hinder its further development, such as limited response rates and poor tumor permeability. The efficiency of tumor immunotherapy is also closely linked to the structure and function of the immune microenvironment where the tumor resides. Recently, nanoparticle‐based tumor immune microenvironment (TIME) modulation strategies have attracted a great deal of attention in cancer immunotherapy. This is primarily due to the distinctive physical characteristics of nanoparticles, which enable them to effectively infiltrate the TIME and selectively modulate its key constituents. This paper reviews recent advances in nanoparticle engineering to improve anti‐cancer immunotherapy. Emerging nanoparticle‐based approaches for modulating immune cells, tumor stroma, cytokines and immune checkpoints are discussed, aiming to overcome current challenges in the clinic. In addition, integrating immunotherapy with various treatment modalities such as chemotherapy and photodynamic therapy can be facilitated through the utilization of nanoparticles, thereby enhancing the efficacy of cancer treatment. The future challenges and opportunities of using nanomaterials to reeducate the suppressive immune microenvironment of tumors are also discussed, with the aim of anticipating further advancements in this growing field. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
33. Catalyst‐Free Synthesis of Thiosulfonates and 3‐Sulfenylindoles from Sodium Sulfinates in Water.
- Author
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Li, Shaoke, Huang, Zijun, Wang, Xin, Yingxiong, Hui, Niu, Guohao, Chen, Ziyan, and Zhang, Zhenlei
- Abstract
This paper presents a green and efficient aqueous‐phase method for the synthesis of thiosulfonates, which has the benefits of no need for catalysts or redox reagents and a short reaction time, providing a method with great economic value for synthesizing thiosulfonates. Furthermore, 3‐Sulfenylindoles can be easily synthesized using this method, which expands the potential applications of this reaction. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. Unravelling the Role of Free Radicals in Photocatalysis.
- Author
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Chen, Yao, Xu, Shuyang, Fang Wen, Chun, Zhang, Hanyun, Zhang, Ting, Lv, Fujian, Yue, Yinghong, and Bian, Zhenfeng
- Abstract
Free radicals are increasingly recognized as active intermediate reactive species that can participate in various redox processes, significantly influencing the mechanistic pathways of reactions. Numerous researchers have investigated the generation of one or more distinct photogenerated radicals, proposing various hypotheses to explain the reaction mechanisms. Notably, recent research has demonstrated the emergence of photogenerated radicals in innovative processes, including organic chemical reactions and the photocatalytic dissolution of precious metals. To harness the potential of these free radicals more effectively, it is imperative to consolidate and analyze the processes and action modes of these photogenerated radicals. This conceptual paper delves into the latest advancements in understanding the mechanics of photogenerated radicals. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. Suppressing Cis/Trans ‘Ring‐Flipping’ in Organoaluminium(III)‐2‐Pyridyl Dimers–Design Strategies Towards Lewis Acid Catalysts for Alkene Oligomerisation.
- Author
-
Choudhury, Dipanjana, Lam, Ching Ching, Farag, Nadia L., Slaughter, Jonathan, Bond, Andrew D., Goodman, Jonathan M., and Wright, Dominic S.
- Abstract
Owing to its high natural abundance compared to the commonly used transition (precious) metals, as well as its high Lewis acidity and ability to change oxidation state, aluminium has recently been explored as the basis for a range of single‐site catalysts. This paper aims to establish the ground rules for the development of a new type of cationic alkene oligomerisation catalyst containing two Al(III) ions, with the potential to act co‐operatively in stereoselective assembly. Five new dimers of the type [R2Al(2‐py′)]2 (R=Me,
i Bu; py′=substituted pyridyl group) with different substituents on the Al atoms and pyridyl rings have been synthesised. The formation of the undesiredcis isomers can be suppressed by the presence of substituents on the 6‐position of the pyridyl ring due to steric congestion, with DFT calculations showing that the selection of thetrans isomer is thermodynamically controlled. Calculations show that demethylation of the dimers [Me2Al(2‐py′)]2 with Ph3C+ to the cations [{MeAl(2‐py’)}2(μ‐Me)]+ is highly favourable and that the desiredtrans disposition of the 2‐pyridyl ring units is influenced by steric effects. Preliminary experimental studies confirm that demethylation of [Me2Al(6‐MeO‐2‐py)]2 can be achieved using [Ph3C][B(C6F5)4]. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
36. [Gd(HB‐DO3A)]: Equilibrium, Dissociation Kinetic and Structural Differences in a Simple Homolog of [Gd(HP‐DO3A)] (Prohance®)
- Author
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Versolatto, Silvia, Boccalon, Mariangela, Guidolin, Nicol, Travagin, Fabio, Alessio, Enzo, Aime, Silvio, Balducci, Gabriele, Giovenzana, Giovanni B., and Baranyai, Zsolt
- Abstract
[Gd(
HP‐DO3A )] (gadoteridol) as an active compound of ProHance® is a widely employed contrast agent in clinical MRI scans in the last 30 years. Recent concerns about the long‐term retention of gadolinium‐based contrast agents (GBCAs) led to a deeper investigation of the structural features underlying the integrity of the paramagnetic metal complex. Several human and nonclinical studies have noted marked differences among the macrocyclic GBCAs, with the least retention of Gd traces and most rapid elimination consistently being reported for [Gd(HP‐DO3A )]. It was deemed of interest to assess how minor structural/electronic changes associated to the ligand structure may affect basic properties of the metal complex with several [Gd(HP‐DO3A )] analogues synthesized and characterized in the last years. We recently reported that the closest homolog of [Gd(HP‐DO3A )],i. e .: [Gd(HB‐DO3A )], in which a (±)‐2‐hydroxy‐1‐propyl pendant arm is replaced by a (±)‐2‐hydroxy‐1‐butyl moiety, showed a significantly different retention behaviour in the model interaction with collagen, despite the apparently very minor structural difference. In this paper we report a comprehensive study of the structural, thermodynamic, kinetic and relaxation properties of [Gd(HB‐DO3A )], compared to the parent [Gd(HP‐DO3A )] and to other closely related macrocyclic GBCAs to assess whether very minor structural changes can modulate the physico‐chemical properties of Gd3+ complexes. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
37. Extended Tripodal Hydrotris(indazol‐1‐yl)borate Ligands as Ruthenium‐Supported Cogwheels for On‐Surface Gearing Motions.
- Author
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Omoto, Kenichiro, Shi, Menghua, Yasuhara, Kazuma, Kammerer, Claire, and Rapenne, Gwénaël
- Subjects
ARYL group ,BORATES ,RUTHENIUM compounds ,SINGLE crystals ,CRYSTAL structure - Abstract
This paper reports the synthesis of ruthenium‐based molecular gear prototypes composed of a brominated or non‐brominated pentaphenylcyclopentadienyl ligand as an anchoring unit and a tripodal ligand with aryl‐functionalized indazoles as a rotating cogwheel. Single crystal structures of the ruthenium complexes revealed that the appended aryl groups increase the apparent diameter of the cogwheel rendering them larger than the diameter of the anchoring units and consequently making them suitable for intermolecular gearing motions once the complexes will be adsorbed on a surface. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
38. Reagent‐Controlled Regioselective Intramolecular [2+2] Cycloaddition between Vinylsilanes and Allenes.
- Author
-
Yoshioka, Shohei, Takehara, Tsunayoshi, Suzuki, Takeyuki, and Arisawa, Mitsuhiro
- Subjects
ALLENE ,VINYLSILANES ,DOUBLE bonds ,ATOMIC radius ,GOLD catalysts ,RING formation (Chemistry) - Abstract
This paper provides the first report of the intramolecular [2+2] cycloaddition of vinylsilane. The [2+2] cycloaddition of allenes is a useful reaction that can synthesize cyclobutanes. However, no previous works have attempted to control the regioselectivity between the two double bonds of allenes only by changing the reaction conditions, although there have been some reports of the regioselective [2+2] cycloaddition of allenes by changing the substrate. In this study, we have succeeded in controlling intramolecular [2+2] cycloaddition reactions at the proximal and distal positions of allenes simply by changing the reaction conditions. We found that the atomic radius of silicon is very important for perfect control of the reaction's sites. The structures of all key compounds were determined by the crystal sponge method which could identify the structures of liquid compounds. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
39. Theoretical and Experimental Investigations of Stable Arylfluorene‐Based Radical‐Type Mechanophores.
- Author
-
Sugita, Hajime, Lu, Yi, Aoki, Daisuke, Otsuka, Hideyuki, and Mikami, Koichiro
- Subjects
THERMAL stability ,PEROXIDES ,POLYMERS - Abstract
Radical‐type mechanophores (RMs) can undergo homolytic cleavage of their central C−C bonds upon exposure to mechanical forces, which affords radical species. Understanding the characteristics of these radical species allows bespoke mechanoresponsive materials to be designed and developed. The thermal stability of the central C−C bonds and the oxygen tolerance of the generated radical species are crucial characteristics that determine the functions and applicability of such RM‐containing mechanoresponsive materials. In this paper, we report the synthesis and characterization of two series of arylfluorene‐based RM derivatives, that is, 9,9'‐bis(5‐methyl‐2‐pyridyl)‐9,9'‐bifluorene (BPyF) and 9,9'‐bis(4,6‐diphenyl‐2‐triazyl)‐9,9'‐bifluorene (BTAF). BPyF and BTAF derivatives were synthesized without generating any peroxides initially, albeit that BPyF slowly converted to the corresponding peroxide in solution. DFT calculations revealed the importance of the thermodynamic stability and the values of the α‐SOMO levels of the corresponding radical species for their thermal stability and oxygen tolerance. Furthermore, the mechanochromism of BTAF was demonstrated by ball‐milling a BTAF‐centered polymer, which was synthesized by atom‐transfer radical polymerization (ATRP). [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
40. Recent Advances on High‐Capacity Sodium Manganese‐Based Oxide Cathodes for Sodium‐ion Batteries.
- Author
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Cao, Yuge, Xiao, Meijing, Sun, Xuzhou, Dong, Wujie, and Huang, Fuqiang
- Subjects
CATHODES ,SODIUM ions ,SODIUM ,TRANSITION metal oxides ,STORAGE batteries - Abstract
Sodium manganese‐based oxides (NMO) are attracting huge attention as safe and cost‐effective cathode materials for sodium‐ion batteries (SIBs). To date, one of the most important challenges of NMO‐based cathodes is the relatively low capacity. Therefore, it is of great significance to develop high‐capacity NMO‐based cathodes. Great efforts have been made to enhance the reversible capacity of NMO‐based cathodes, achieving considerable progress not only on electrochemical performance, but also the mechanism of massive sodium ion storage. In this paper, the structure and sodium storage mechanism for typical phases of NMO are reviewed, including P2, P3, O3, tunnel‐type, and spinel‐type NMO‐based cathodes. Strategies for high‐capacity NMO‐based cathodes, such as cationic substitution, anion redox activation, etc are introduced in detail. Last but not least, the future opportunities and challenges for high‐capacity NMO‐based cathode are prospected. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
41. A Simple Substitution on Thyroid Hormones Remarkably Alters the Regioselectivity of Deiodination by a Deiodinase Mimic.
- Author
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Giri, Debasish, Raja, Karuppusamy, and Mugesh, Govindasamy
- Subjects
THYROID hormones ,SMALL molecules ,HYDROGEN bonding ,SELENIUM compounds ,MYOCARDIAL infarction ,THYROID hormone receptors - Abstract
The regioselective deiodinations of L‐thyroxine (T4) play key roles in the thyroid hormone homeostasis. These reactions are catalyzed by three isoforms of the selenoenzymes, iodothyronine deiodinases (Dio1, Dio2 and Dio3), which are highly homologous in nature. Dio1 mediates 5′‐ or 5‐deiodinations of T4 to produce T3 and rT3, respectively. In contrast, Dio2 and Dio3 are selective to 5′‐ or 5‐deiodination to produce T3 and rT3, respectively. Understanding of the regioselectivity of deiodination at the molecular level is important as abnormal levels of thyroid hormone have been implicated in various clinical conditions, such as hypoxia, myocardial infarction, neuronal ischemia and cancer. In this paper, we report that the electronic properties of the iodine atoms in thyroxine (T4) can be modulated through a simple substitution in the 4′‐phenolic moiety. This leads to the change in the regioselectivity of deiodination by different small molecule mimics of Dio enzymes. By using this chemical approach, we also show that the substitution of a strong electron withdrawing group facilitates the removal of all four iodine atoms in the T4 derivative. Theoretical investigations on the hydrogen bonded adducts of T4 with imidazole indicate that the charge on the iodine atoms depend on the nature of hydrogen bond between the −OH group of T4 and the imidazole moiety. While the imidazole can act as either hydrogen bond acceptor (HBA) or hydrogen bond donor (HBD), the protonated imidazole acts exclusively as HBD in T4‐imidazole complex. These studies support the earlier observations that the histidine residue at the active sites of the deiodinases play an important role not only in the substrate binding, but also in altering the regioselectivity of the deiodination reactions. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
42. The HD Reaction of Nitrogenase: a Detailed Mechanism.
- Author
-
Dance, Ian
- Subjects
NITROGENASES ,ACTIVATION energy ,ATOMS ,COINCIDENCE ,KINETIC energy ,GEOLOGICAL carbon sequestration ,MICROBIAL exopolysaccharides - Abstract
Nitrogenase is the enzyme that converts N2 to NH3 under ambient conditions. The chemical mechanism of this catalysis at the active site FeMo‐co [Fe7S9CMo(homocitrate)] is unknown. An obligatory co‐product is H2, while exogenous H2 is a competitive inhibitor. Isotopic substitution using exogenous D2 revealed the N2‐dependent reaction D2+2H++2e−→2HD (the 'HD reaction'), together with a collection of additional experimental characteristics and requirements. This paper describes a detailed mechanism for the HD reaction, developed and elaborated using density functional simulations with a 486‐atom model of the active site and surrounding protein. First D2 binds at one Fe atom (endo‐Fe6 coordination position), where it is flanked by H−Fe6 (exo position) and H−Fe2 (endo position). Then there is synchronous transfer of these two H atoms to bound D2, forming one HD bound to Fe2 and a second HD bound to Fe6. These two HD dissociate sequentially. The final phase is recovery of the two flanking H atoms. These H atoms are generated, sequentially, by translocation of a proton from the protein surface to S3B of FeMo‐co and combination with introduced electrons. The first H atom migrates from S3B to exo‐Fe6 and the second from S3B to endo‐Fe2. Reaction energies and kinetic barriers are reported for all steps. This mechanism accounts for the experimental data: (a) stoichiometry; (b) the N2‐dependence results from promotional N2 bound at exo‐Fe2; (c) different N2 binding Km for the HD reaction and the NH3 formation reaction results from involvement of two different sites; (d) inhibition by CO; (e) the non‐occurrence of 2HD→H2+D2 results from the synchronicity of the two transfers of H to D2; (f) inhibition of HD production at high pN2 is by competitive binding of N2 at endo‐Fe6; (g) the non‐leakage of D to solvent follows from the hydrophobic environment and irreversibility of proton introduction. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
43. Photophysics of Anionic Bis(4H‐imidazolato)CuI Complexes.
- Author
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Seidler, Bianca, Tran, Jens H., Hniopek, Julian, Traber, Philipp, Görls, Helmar, Gräfe, Stefanie, Schmitt, Michael, Popp, Jürgen, Schulz, Martin, and Dietzek‐Ivanšić, Benjamin
- Subjects
ELECTRON density ,BAND gaps ,TIME-resolved spectroscopy - Abstract
In this paper, the photophysical behavior of four panchromatically absorbing, homoleptic bis(4H‐imidazolato)CuI complexes, with a systematic variation in the electron‐withdrawing properties of the imidazolate ligand, were studied by wavelength‐dependent time‐resolved femtosecond transient absorption spectroscopy. Excitation at 400, 480, and 630 nm populates metal‐to‐ligand charge transfer, intraligand charge transfer, and mixed‐character singlet states. The pump wavelength‐dependent transient absorption data were analyzed by a recently established 2D correlation approach. Data analysis revealed that all excitation conditions yield similar excited‐state dynamics. Key to the excited‐state relaxation is fast, sub‐picosecond pseudo‐Jahn‐Teller distortion, which is accompanied by the relocalization of electron density onto a single ligand from the initially delocalized state at Franck‐Condon geometry. Subsequent intersystem crossing to the triplet manifold is followed by a sub‐100 ps decay to the ground state. The fast, nonradiative decay is rationalized by the low triplet‐state energy as found by DFT calculations, which suggest perspective treatment at the strong coupling limit of the energy gap law. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
44. Covalent Organic Frameworks as Electrode Materials for Alkali Metal‐ion Batteries.
- Author
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Cui, Shuzhen, Miao, Wenxing, Peng, Hui, Ma, Guofu, Lei, Ziqiang, Zhu, Lei, and Xu, Yuxi
- Subjects
CARBON-based materials ,ALKALIES ,POROSITY ,ELECTRODES ,COVALENT bonds ,CONJUGATED polymers - Abstract
Covalent organic frameworks (COFs) are a class of porous crystalline polymeric materials constructed by linking organic small molecules through covalent bonds. COFs have the advantages of strong covalent bond network, adjustable pore structure, large specific surface area and excellent thermal stability, and have broad application prospects in various fields. Based on these advantages, rational COFs design strategies such as the introduction of active sites, construction of conjugated structures, and carbon material composite, etc. can effectively improve the conductivity and stability of the electrode materials in the field of batteries. This paper introduces the latest research results of high‐performance COFs electrode materials in alkali metal‐ion batteries (LIBs, SIBs, PIBs and LSBs) and other advanced batteries. The current challenges and future design directions of COFs‐based electrode are discussed. It provides useful insights for the design of novel COFs structures and the development of high‐performance alkali metal‐ion batteries. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. "Bubble‐Diode" Breathable Electrodes for Fast Gas Transport.
- Author
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He, Yi and Tan, Peng
- Abstract
Bubbles arising from wild gas evolution commonly exist in electrochemical systems, particularly in water electrolysis and rechargeable aqueous batteries (e. g. Zn‐air batteries). Substantial energy dissipation occurs due to the obstruction of active sites and ion‐conducting pathways by evolving bubbles. Efforts are made to elucidate effective strategies for fast gas transport, most of which focus on minimizing bubble size and facilitating their timely detachment through complex techniques such as constructing super‐hydrophilic nano‐structure electrodes, flowing electrolytes, and ultrasonic oscillation. Recently, an innovative, facile, and highly efficient method utilizing a breathable electrode design to promote gaseous molecules to the external environment emerges as a promising approach since it avoids remarkable bubble accumulation while remaining free of additional accessories. This paper highlights the origin and evolution of this promising design. Starting with introducing the basic concept of traditional breathable electrodes based on hydrophobic polymer networks and discussing the current progress made in underlying mechanisms, a detailed description of the advanced design inspired by a "bubble‐diode" concept with superior breathability follows. This Concept aims to contribute to a deep understanding of this technology and paves the way for further advancements in this renewable energy era. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. Scaffold Editing of Cubanes into Homocubanes, Homocuneanes via Cuneanes.
- Author
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Takebe, Hiyori and Matsubara, Seijiro
- Subjects
CUBANES ,ISOMERIZATION ,BIOISOSTERES ,EDITING ,CATALYSTS - Abstract
The selective synthesis of cage‐type hydrocarbons through the editing of the highly symmetric molecule cubane can be anticipated as one of the efficient approaches. In this paper, we identify a catalyst that facilitates the efficient scaffold isomerization of cubanes into homocubanes. This approach, which involves the direct synthesis of homocubanol esters, is promising as a novel method for the synthesis of phenoxy bioisosteres. Additionally, we observed that the isomerization of 1,4‐bis(acyloxymethl)cubane results in the generation of both D2‐ and C2‐symmetrical bishomocubanes. The same catalyst was also applied to the isomerization of acyloxymethylcuneanes, producing homocuneanol esters. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. Colloidal and Thermal Stability of Three‐Component Hybrid Materials Containing Clay Mineral, Polysaccharide and Surfactant.
- Author
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Godek, Ewelina, Maciołek, Urszula, Kosińska‐Pezda, Małgorzata, Byczyński, Łukasz, Nowicka, Aldona, and Grządka, Elżbieta
- Subjects
HYBRID materials ,COLLOIDAL stability ,POLYSACCHARIDES ,CLAY minerals ,ALGINIC acid ,HALLOYSITE ,CELLULOSE fibers - Abstract
The paper presents the colloidal and thermal stability of the three‐component hybrid materials containing halloysite, polysaccharides (alginic acid, cationic cellulose and hydroxyethyl cellulose) and Tritons. TX‐100, TX‐165 and TX‐405 were used as non‐ionic surfactants. Stability and other properties of the hybrid materials were tested by the following methods: UV–Vis, TGA (thermogravimetric analysis) and DSC (differential scanning calorimetry), CHN (elemental analysis), SEM‐EDX (scanning electron microscopy with energy dispersive X‐ray spectroscopy) and tensiometry. According to the results with the increasing polymer concentration the colloidal stability of the tested systems also increases. Moreover, the addition of the surfactants causes the increase of polysaccharide adsorption but the colloidal stability of the tested systems decreases due to large weights of formed aggregates. As follows from the thermal analysis, the comparison of the TG/DTG‐DSC curves obtained for the investigated polymers confirms that their thermal decomposition courses have some common features. The obtained results have the application potential in the formation of the materials for the pollutants removal from water and sewages. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. Direct Lithium Extraction Using Intercalation Materials.
- Author
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Wang, Jing and Koenig, Gary M.
- Subjects
CHEMICAL processes ,SUSTAINABLE development ,ELECTRIC vehicles ,ELECTRIC vehicle batteries ,LITHIUM ,CHEMICAL purification - Abstract
Worldwide lithium demand has surged in recent years due to increased production of Li‐ion batteries for electric vehicles and stationary storage. Li supply and production will need to increase such that the transition towards increased electrification in the energy sector does not become cost prohibitive. Many countries have taken policy steps such as listing Li as a critical mineral. Current commercial Li mining is mostly from dedicated mine sources, including ores, clays, and brines. The conventional ways to extract Li+ from those resources are through chemical processing and includes steps of calcination, leaching, precipitation, and purification. The environmental and economic sustainability of conventional Li processing has recently received increased scrutiny. Routes such as direct Li+ extraction may provide advantages relative to conventional Li+ extraction technologies, and one possible route to direct Li+ extraction includes leveraging intercalation materials. Intercalation material processing has recently demonstrated high selectivity towards Li+ as opposed to other cations. Reviews and reports of direct Li+ extraction with intercalation materials are limited, even as this technology has started to show promise in smaller‐scale demonstrations. This paper will review selective Li+ extraction via intercalation materials, including both electrochemical and chemical methods to drive Li+ in and out, and efforts to characterize the Li+ insertion/deinsertion processes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Elucidating the Electronic Nature of Rh‐based Paddlewheel Catalysts from 103Rh NMR Chemical Shifts: Insights from Quantum Mechanical Calculations.
- Author
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Gui, Xin, Sorbelli, Diego, Caló, Fabio P., Leutzsch, Markus, Patzer, Michael, Fürstner, Alois, Bistoni, Giovanni, and Auer, Alexander A.
- Subjects
RHODIUM catalysts ,NUCLEAR magnetic resonance spectroscopy ,CATALYST structure ,LIGANDS ,CATALYSTS ,ELECTRONIC structure - Abstract
The tremendous importance of dirhodium paddlewheel complexes for asymmetric catalysis is largely the result of an empirical optimization of the chiral ligand sphere about the bimetallic core. It was only recently that a H(C)Rh triple resonance 103Rh NMR experiment provided the long‐awaited opportunity to examine – with previously inconceivable accuracy – how variation of the ligands impacts on the electronic structure of such catalysts. The recorded effects are dramatic: formal replacement of only one out of eight O‐atoms surrounding the metal centers in a dirhodium tetracarboxylate by an N‐atom results in a shielding of the corresponding Rh‐site of no less than 1000 ppm. The current paper provides the theoretical framework that allows this and related experimental observations made with a set of 19 representative rhodium complexes to be interpreted. In line with symmetry considerations, it is shown that the shielding tensor responds only to the donor ability of the equatorial ligands along the perpendicular principal axis. Axial ligands, in contrast, have no direct effect on shielding but may come into play via the electronic cis ${cis}$ ‐effect that they exert onto the neighboring equatorial sites. On top of these fundamental interactions, charge redistribution within the core as well as the electronic trans ${trans}$ ‐effect of ligands of different donor strengths is reflected in the recorded 103Rh NMR shifts. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. Easy to Use DFT Approach for Computational pKa Determination of Carboxylic Acids.
- Author
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Pezzola, Silvia, Venanzi, Mariano, Galloni, Pierluca, Conte, Valeria, and Sabuzi, Federica
- Subjects
CYANO group ,ACETIC acid ,GROUP 15 elements ,CARBOXYLIC acids ,SOLVATION ,FUNCTIONALS - Abstract
In pKa computational determination, the challenge in exploring and fostering new methodologies and approaches goes in parallel with the amelioration of computational performances. In this paper a "ready to use methodology" has been compared to other strategies, such as the re‐shaping in solvation cavity (Bondi radius re‐shaping), wanting to assess its reliability in predicting the pKa of a broad list of carboxylic acids. Thus, the functionals B3LYP and CAM‐B3LYP have been selected, using SMD as continuum solvation model. Exploiting our previous results, two water molecules were made explicit on the reaction centre. Data show that our model (CAM‐B3LYP/2H2O) is capable to accurately predict pKa, leading to mean absolute error (MAE) values lower than 0.5. Noteworthy, good results were achieved in computing the pKa of substituents bearing nitro and cyano groups. Focusing on B3LYP, eventually remarkable outputs were obtained only when Bondi correction was applied to the complex with two water molecules. Hence, massive outcomes were obtained in foreseeing the trichloro and trifluoro acetic acid pKa. These findings demonstrated that no complex level of theory nor external factor is required to accurately predict carboxylic acids pKa, with MAE well below 0.5 units. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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