2,813 results on '"FUNCTIONAL groups"'
Search Results
2. Water structures in tip-charged carbon nanotubes.
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Ono, Yûi, Yamamoto, Eiji, and Yasuoka, Kenji
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NANOFLUIDIC devices , *ELECTRIC fields , *MEMBRANE separation , *HELICAL structure , *FUNCTIONAL groups , *CARBON nanotubes - Abstract
Carbon nanotubes (CNTs) have potential applications in separation membranes and nanofluidic devices. It is well known that the behavior of water molecules confined in CNTs is affected by surface functional groups and external electric fields, leading to structural changes. The understanding of these structural changes of water within various CNTs is crucial, particularly in the context of material separation. While there have been many investigations into the effects of individual specific functional groups, a comprehensive understanding of the effect of these functional groups and the electric fields they generate on water molecules remains elusive. In this study, we investigate the properties of water molecules in tip-charged CNTs of (8,8), (10,10), and (12,12) chiral vectors with positive charges at one tip and negative charges at the other tip. Abstraction of ionized functional groups as tip charges enables a comprehensive understanding that is independent of individual functional groups. The symmetrically arranged tip-charges spontaneously generate a strong and symmetric electric field in the CNTs. However, the strength and directionality of the electric field are non-uniform and complex. In the interiors of (8,8) and (10,10) tip-charged CNTs, helical and square structures, which have disturbances caused by the non-uniformity of the electric field, are observed. The properties of the water molecules differed significantly in the center of the CNTs and near positive and negative charges, despite the electric field symmetry. In (12,12) tip-charged CNTs with 12 charges, a local ring structure is observed in the vicinity of negative charges but not in the vicinity of positive charges. It is concluded that the water structures in tip-charged CNTs have different characteristics from those in plain CNTs under a uniform electric field. [ABSTRACT FROM AUTHOR]
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- 2024
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3. KeldyshQFT: A C++ codebase for real-frequency multiloop functional renormalization group and parquet computations of the single-impurity Anderson model.
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Ritz, Nepomuk, Ge, Anxiang, Walter, Elias, Aguirre, Santiago, von Delft, Jan, and Kugler, Fabian B.
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RENORMALIZATION group , *ANDERSON model , *STATISTICAL correlation , *DATA structures , *FUNCTIONAL groups - Abstract
We provide a detailed exposition of our computational framework designed for the accurate calculation of real-frequency dynamical correlation functions of the single-impurity Anderson model in the regime of weak to intermediate coupling. Using quantum field theory within the Keldysh formalism to directly access the self-energy and dynamical susceptibilities in real frequencies, as detailed in our recent publication [Ge et al., Phys. Rev. B 109, 115128 (2024)], the primary computational challenge is the full three-dimensional real-frequency dependence of the four-point vertex. Our codebase provides a fully MPI+OpenMP parallelized implementation of the functional renormalization group (fRG) and the self-consistent parquet equations within the parquet approximation. It leverages vectorization to handle the additional complexity imposed by the Keldysh formalism, using optimized data structures and highly performant integration routines. Going beyond the results shown in the previous publication, the code includes functionality to perform fRG calculations in the multiloop framework, up to arbitrary loop order, including self-consistent self-energy iterations. Moreover, implementations of various regulators, such as hybridization, interaction, frequency, and temperature, are supplied. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Tuning structural and electronic properties of metal-organic framework 5 by metal substitution and linker functionalization.
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Edzards, Joshua, Saßnick, Holger-Dietrich, Andreo, Julia Santana, and Cocchi, Caterina
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METAL-organic frameworks , *ALKALINE earth metals , *ENERGY conversion , *VALENCE bands , *FUNCTIONAL groups , *METALS - Abstract
The chemical flexibility of metal-organic frameworks (MOFs) offers an ideal platform to tune structure and composition for specific applications, from gas sensing to catalysis and from photoelectric conversion to energy storage. This variability gives rise to a large configurational space that can be efficiently explored using high-throughput computational methods. In this work, we investigate from first principles the structural and electronic properties of MOF-5 variants obtained by replacing Zn with Be, Mg, Cd, Ca, Sr, and Ba and by functionalizing the originally H-passivated linkers with CH3, NO2, Cl, Br, NH2, OH, and COOH groups. To build and analyze the resulting 56 structures, we employ density-functional theory calculations embedded in an in-house developed library for automatized calculations. Our findings reveal that structural properties are mainly defined by metal atoms and large functional groups, which distort the lattice and modify coordination. The formation energy is largely influenced by functionalization and enhanced by COOH and OH groups, which promote the formation of hydrogen bonds. The charge distribution within the linker is especially influenced by functional groups with electron-withdrawing properties, while the metal nodes play a minor role. Likewise, the bandgap size is crucially determined by ligand functionalization. The smallest gaps are found with NH2 and OH groups, which introduce localized orbitals at the top of the valence band. This characteristic makes these functionalizations particularly promising for the design of MOF-5 variants with enhanced gas uptake and sensing properties. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Isolation of sulfate polysaccharides (Ulvan) from the green algae of Ulva lactuca and characterization of its functional groups.
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Khaerunnisa, Mira, Arfah, Rugaiyah A., and Permatasari, Nur Umriani
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GREEN algae , *HYDROCHLORIC acid , *FUNCTIONAL groups , *ULVA , *SUGAR , *POLYSACCHARIDES - Abstract
Ulvan is a water-soluble polysaccharide containing a sulfate group isolated from Ulva, a green alga with unique structural properties and the potential to be developed in biomaterials supported by biological activities such as antioxidant, antibacterial, anticoagulant and immunomodulatory. This research aims to isolate ulvan from Ulva lactuca and to study the characteristic of the ulvan functional groups. The methods used were extraction with hydrochloride acid 0.1 M and precipitation using ethanol 96% to obtain a percent yield of ulvan. The ulvan structure was characterized by UV-Vis and FTIR spectrophotometry. The amount of sugar was determined using phenol-sulfuric acid method. The results showed the yield of ulvan produced about 23.34% at maximum UV-Vis wavelength of 205 nm and the FTIR spectra significant at 854.47-1097.50 cm−1 of sulphated polysaccharides region. The sugar content of the isolated ulvan which extracted using hydrochloric acid 0.1 M was 1.4124 mg/mL. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Effect of lubricant functional groups on tribological properties of epoxy/graphene composites.
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Zheng, Wenxuan, Zhang, Guoliang, Qi, Jian, Lu, Shichao, and Li, Yang
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DRY friction ,CARBOXYL group ,FUNCTIONAL groups ,OLEIC acid ,HYDROXYL group ,INTERFACIAL friction ,LUBRICATION & lubricants - Abstract
The functional group in the molecular chain of lubricants is a key factor for a boundary lubricating film, which can further enhance the friction performance by interfacial tribochemistry. In this paper, the tribological behavior of epoxy/graphene (EP/Gra) composites was investigated through varying lubrication conditions, including dry friction, or different lubricants (such as water, hexadecane, oleylamine, and oleic acid). The porosity and Shore hardness (SHD) of the EP composites were significantly improved by the addition of graphene. Results showed that the porosity of the EP/0.75 wt.% Gra composites was reduced by 75.6% and their SHD increased by 5.4 compared with the EP/0.05 wt.% Gra composites. The average coefficient of friction (COF) of the composites was reduced by at least 27.3% under dry friction conditions. For water as lubricant, the EP/0.5 wt.% Gra composite exhibited the lowest COF (0.0455). The EP/0.75 wt.% Gra composite displayed the lowest COF (0.0466) when hexadecane acted as lubricant. By contrast, EP/0.05 wt.% Gra showed the lowest COF (0.0389) with oleylamine as lubricant, and the EP/0.25 wt.% Gra composites gave the lowest COF (0.0433) under oleic acid. The amine group of oleylamine reacted with the EP group to form a hydroxyl group, resulting in a polymer with low friction adhered to the friction interface. Simultaneously, the EP group reacted with the carboxyl group, forming a network of hydrogen bonds with graphene, which reduced the shear stress on the friction interface. Therefore, the functional groups of lubricants have a vital influence on the tribological properties of frictional composites, which may provide a new approach to solving the problem of wear. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Total synthesis of (+)-oridamycins A and B.
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Murmu, Ranjit, Kundu, Sourav, Majhi, Moumita, Pal, Souvik, Mondal, Abhishek, and Bisai, Alakesh
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METHYL formate , *FUNCTIONAL groups , *MOIETIES (Chemistry) , *RING formation (Chemistry) , *SKELETON , *CARBAZOLE - Abstract
We have accomplished a unified strategy to achieve the structurally intriguing indolosesquiterpene alkaloids with diverse biological activity, xiamycin A (1a), xiamycin A methyl ester (1b) and oridamycins A (2a), and B (2b), which possesses a complex 6/6/6/5/6-fused pentacyclic skeleton bearing a carbazole moiety fused with a highly functionalized trans-decalin motif. Lewis acid-mediated epoxy-ene cyclization establishes the required pentacyclic scaffold with the installation of the four contiguous stereogenic centers. Further oxidative cleavage of the vinyl functionality, followed by successive functional group interconversions, completed the total synthesis of the indolosesquiterpene alkaloids. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Photoredox cross-dehydrogenative C(sp2)–C(sp3) coupling of heteroarenes with secondary amines through 1,5-HAT.
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Srinivasu, Vinjamuri, Pattanaik, Swadhin, and Sureshkumar, Devarajulu
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ALIPHATIC amines , *SECONDARY amines , *FUNCTIONAL groups , *BIOCHEMICAL substrates , *HETEROARENES - Abstract
The functionalization of α-C(sp3)–H bonds in amines has become a focal point of contemporary research. Here, we report a new approach utilizing photocatalysis α-C(sp3)–H bond functionalization in alicyclic and aliphatic secondary amines facilitated by intramolecular 1,5-hydrogen atom transfer (HAT). This finding unlocks a sustainable method for rapidly constructing complex heterocyclics via cross-dehydrogenative C–C coupling of protected amines and nitrogen-containing heterocycles. This protocol boasts broad applicability to various substrates, exhibits tolerance to numerous functional groups, and supports the late-stage modification of drug molecules. [ABSTRACT FROM AUTHOR]
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- 2024
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9. A selective photoinduced radical O-alkenylation of phenols and naphthols with terminal alkynes.
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Praveen Kumar, V., Athira, C. S., Mohan, B., Priya, S., and Sasidhar, B. S.
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BENZOFURAN synthesis , *RADICALS (Chemistry) , *FUNCTIONAL groups , *ALKYNES , *PHENOLS - Abstract
The visible light-promoted O-alkenylation of phenols and naphthols with terminal alkynes is achieved using 2,4,6-tris(4-fluorophenyl)pyrylium tetrafluoroborate (T(p-F)PPT) as a photocatalyst at room temperature without the need of any external ligand or additive. Apart from its excellent functional group tolerance, the protocol described herein represents an appealing alternative strategy to classical transition-metal catalysed hydroarylation reactions. Mechanistic investigations revealed that the reaction involves a radical pathway. The utility of the hydroarylated products for the synthesis of fused benzofurans via a one-pot annulation was also demonstrated. Herein, we report the first intermolecular radical hydroarylation of alkynes. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Experimental investigation of the water bypass phenomenon in light oil reservoirs using a glass micromodel and sand cores with a hydrophobic material.
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Adjou, Zakaria, Dobbi, Abdelmadjid, and Hamid, Lebtahi
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OIL field flooding , *SILICA sand , *PETROLEUM reservoirs , *CORE materials , *CONTACT angle , *WETTING , *FUNCTIONAL groups - Abstract
A large volume of water is bypassing oil and comes up without being able to push it out from the reservoir after organic material adsorption. This work investigates hydrophobicity effect on rock wettability, oil recovery, and relative permeability. The μXRF was used to characterize sand cores, and a contact angle goniometer to determine fluids contact angle. Oil recovery was evaluated by measuring the incremental oil volume recovered in a glass and PVC capillary designed micromodel. Relative permeability was studied using the steady state method, and the wettability was determined by the Amott method. The results show that cores are mainly composed of quartz 86.04%. Oil recovery was 30.50% for oil-wet state; where the wettability index was −0.283. Thereafter, it has been demonstrated that the surfactant solution increases the oil recovery with 23.54 ℅. Adsorption of surfactants on functional groups of PVC change the contact angle between water and PVC's surface from 112° to 39°, decrease the IFT and restore the water-wet state. PVC debris presents efficient new method to determine the water by pass effect on oil recovery. The findings of this study help for better understanding the surfactant-oil displacements during water flooding in light oil reservoirs with impaired wettability. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Photoredox‐Catalyzed Metal‐Free Regio‐ & Stereoselective C(sp2)–H Amination of Enamides with N‐Aminopyridium Salts.
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Qin, Zheng‐Bao, Ni, Kun, Wang, Li, Wu, Xiao‐Di, Zhang, Yu, and Zhao, Kai
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RADICALS (Chemistry) , *FUNCTIONAL groups , *AMINATION , *ENVIRONMENTAL economics , *CATALYSIS - Abstract
Comprehensive Summary: A visible‐light‐induced photoredox‐catalyzed regioselective and stereoselective C(sp2)–H amination of enamides with bench‐stable and easily accessible N‐aminopyridium salts is developed, affording synthetically and biologically prominent vicinal 1,2‐diamine scaffolds with broad substrate scope and excellent functional group compatibility. The transformation proceeded through a radical pathway involving the Giese addition of the relatively electrophilic N‐centered sulfonamidyl radical species to nucleophilic β‐olefinic position of enamides followed by the ensuing single electron oxidation and β‐H elimination, delivering geometrically‐defined Z‐configured β‐sulfonamidylated enamides. The operational simplicity, environmental friendliness and cost efficiency of this methodology allowed it to pave a new avenue to enrich the arsenal of synthetically crucial functionalized enamides and their related derivatives. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Asymmetric Transfer Hydrogenation of Stable NH Imines for the Synthesis of Enantiopure α‐Chiral Primary Amines.
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Zhang, Mangang, Li, Hui, Wu, Keqin, Rong, Nianxin, Lin, Shaoquan, Yang, Hua, and Yin, Qin
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TRANSFER hydrogenation , *IMINES , *FUNCTIONAL groups , *AMINES , *ANILINE - Abstract
Comprehensive Summary: Although it offers a direct route to access synthetically valuable α‐chiral primary amines, asymmetric transfer hydrogenation of NH imines has been rarely studied, due in large part to the inaccessibility and instability of NH imines. Herein, we report a Rh‐catalyzed asymmetric transfer hydrogenation of a kind of novel and stable NH imines which are prepared via condensation of easily available sulfonylated 2'‐aminoacetophenones with NH3 in methanol. With this method, enantioenriched chiral 2‐(1‐aminoalkyl)anilines, which are privileged pharmacore groups, have been synthesized with good functional group compatibility, and with up to 99% ee. A gram‐scale reaction using 0.2 mol% of catalyst has been successfully performed to highlight the practicality. Furthermore, the products can be derivatized into enantiopure bioactive molecules as well as chiral tridentate ligands for metal catalysis. [ABSTRACT FROM AUTHOR]
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- 2024
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13. Enantioselective Alkylation of Aldehydes with Organoborons Enabled by Nickel/N‐Heterocyclic Carbene Catalysis†.
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Liu, Song‐Yang, Wang, Zi‐Chao, and Shi, Shi‐Liang
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LIGANDS (Chemistry) , *ALKYLATION , *FUNCTIONAL groups , *CHEMOSELECTIVITY , *ALDEHYDES - Abstract
Comprehensive Summary: Transition‐metal‐catalyzed asymmetric alkylation of aldehydes represents a straightforward strategy for the synthesis of chiral secondary alcohols. However, efficient methods using organoborons as coupling reagents are rare. Herein, we report a highly enantioselective nickel‐catalyzed alkylation reaction of aldehydes, using readily available alkylborons as nucleophiles. A wide variety of chiral secondary alcohols were prepared from commercially available aldehydes with high yields. The key to the excellent enantioselectivity and chemoselectivity was the employment of a bulky C2‐symmetric chiral NHC ligand. This protocol features excellent enantiocontrol, mild conditions, and good functional group compatibility. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Nickel/Photoredox Dual Catalytic Chan‐Lam Coupling of Aryl Azides and Arylboric Acids.
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Ge, Xia, Ji, Haojie, and Lu, Hongjian
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COUPLING agents (Chemistry) , *DRUG synthesis , *CHARGE exchange , *ORGANIC synthesis , *FUNCTIONAL groups - Abstract
Comprehensive Summary: Unsymmetrical diarylamines are crucial components in many pharmaceuticals and functional materials. In this study, we introduce an efficient Chan‐Lam cross‐coupling method that utilizes phenylboronic acids and aryl azides as coupling agents in a redox‐neutral environment, enabled by a synergistic nickel/photoredox catalytic system. This approach leverages a proton‐coupled electron transfer mechanism to bypass the typical nitrene pathway associated with aryl azides, which is prone to intramolecular rearrangement, C—H amination, and reductive hydrogenation. Notably, our method exhibits broad compatibility with a variety of functional groups, including those derived from pharmaceuticals, demonstrating its versatile potential in organic synthesis and drug modification. [ABSTRACT FROM AUTHOR]
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- 2024
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15. Photoinduced Perfluoroalkyloximation of Alkenes with Simple Perfluoroalkyl Halides.
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Li, Wei, Li, Zhongji, Zhong, Deliang, Wang, Nianxing, and Li, Huaifeng
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DRUG synthesis , *FUNCTIONAL groups , *ALKENES , *INDOLE compounds , *OXIMES - Abstract
Comprehensive Summary: In this paper, the difunctionalizative perfluoroalkyloximation of alkenes has been developed for the first time. This photochemical method allows for the synthesis of various perfluoroalkyl ethanone oximes with excellent regioselectivity and good functional group tolerance. Our method employs the most common perfluoroalkyl source, perfluoroalkyl iodides, as Rf reagents. Besides long‐chain perfluoroalkyl groups, this approach could be extended to incorporating additional groups, including trifluoromethyl, difluoromethyl, sulfonyl, and malonate, selectively into olefins, resulting in a range of β‐substituted ethanone oximes. Notably, the potential of this method in the Fukuyama indole synthesis, generating novel 2‐perfluoroalkylated 3‐(α‐oximidobenzyl)indoles via a radical cascade mechanism with 2‐vinylphenylacryloyl isocyanate as the radical acceptor, presents a compelling avenue for drug synthesis. The protocol is efficient, scalable, and useful for late‐stage modification of bioactive molecules. [ABSTRACT FROM AUTHOR]
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- 2024
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16. Photocatalytic C(sp3)‐H gem‐Difluoroallylation and Alkylation with Alkenes via a Base‐Assisted Formal 1,2‐Hydrogen Atom Transfer of Amidyl Radicals.
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Tang, Meifang, Feng, Bingbing, Bao, Yanyang, Xu, Zhongtian, Huang, Chao, Zheng, Hanliang, Zhu, Gangguo, Wang, Yanan, and Yuan, Zheliang
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RADICALS (Chemistry) , *DENSITY functional theory , *FUNCTIONAL groups , *ALKENES , *PHOTOCATALYSIS - Abstract
Comprehensive Summary: Compared to well‐established 1,5‐HAT of N‐centered radicals, the synthetic applications of 1,2‐HAT process were scarce due to the high barrier and constrained three‐membered transition state. Here, we have developed a novel C(sp3)‐H gem‐difluoroallylation via a base assisted formal 1,2‐HAT of amidyl radicals with the reductive quenching cycle of photocatalyst. This transformation enables the efficient formation of α‐aminoalkyl radicals via 1,2‐HAT and showcases good functional group tolerance. Our preliminary mechanistic experiments, along with Density Functional Theory (DFT) calculations demonstrate the feasibility of 1,2‐HAT of amidyl radicals, especially when assisted by a base. Furthermore, our method also succeeds in the Giese addition of electron‐deficient alkenes as well as styrene. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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17. Enantioselective Alkylation of Aldehydes with Organoborons Enabled by Nickel/N‐Heterocyclic Carbene Catalysis†.
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Liu, Song‐Yang, Wang, Zi‐Chao, and Shi, Shi‐Liang
- Subjects
LIGANDS (Chemistry) ,ALKYLATION ,FUNCTIONAL groups ,CHEMOSELECTIVITY ,ALDEHYDES - Abstract
Comprehensive Summary: Transition‐metal‐catalyzed asymmetric alkylation of aldehydes represents a straightforward strategy for the synthesis of chiral secondary alcohols. However, efficient methods using organoborons as coupling reagents are rare. Herein, we report a highly enantioselective nickel‐catalyzed alkylation reaction of aldehydes, using readily available alkylborons as nucleophiles. A wide variety of chiral secondary alcohols were prepared from commercially available aldehydes with high yields. The key to the excellent enantioselectivity and chemoselectivity was the employment of a bulky C2‐symmetric chiral NHC ligand. This protocol features excellent enantiocontrol, mild conditions, and good functional group compatibility. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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18. Iodide ion-enabled highly regioselective α-C(sp3)–H triazolization of ethers with N-sulfonyl-1,2,3-triazoles.
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Deng, Yaqi, Yin, Jiabin, Hu, Zongjing, Xue, Jian, Ji, Jian, Zhu, Tong, and Liu, Shunying
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ETHERS , *RADICALS (Chemistry) , *IODIDES , *FUNCTIONAL groups , *CYCLIC ethers - Abstract
An efficient iodide ion (I−)-enabled method for direct α-C(sp3)–H triazolization of ethers via a radical cross-coupling has been developed for regioselective construction of N2-substituted hemiaminal ethers. The developed C(sp3)–H triazolization reaction features the resulting products in good yields (up to 90%) and an excellent functional group tolerance to various ethers, including cyclic and linear ethers. Preliminary mechanistic study and DFT calculation investigation indicate that the reaction proceeds via a SN2-like desulfonylation radical coupling process and an (I−)-involved ternary complex is responsible for the high conversion ratio and the high regioselectivity. I− not only promotes the process but also prevents the in situ generated carbon-centered radicals (CCRs) from being oxidized into carbon cations in an oxidative environment. [ABSTRACT FROM AUTHOR]
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- 2024
- Full Text
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19. Metal-free photoinduced generation and alkynylation of carbamoyl radicals: a facile synthesis of alkynyl amides.
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Duan, Yurong, Zhang, Kai, Xing, Tongtong, Bai, Yubin, Li, Jinfeng, Yang, Xiaojun, Zhao, Yu, and Zhang, Qiuyu
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AMIDE derivatives , *RADICALS (Chemistry) , *FUNCTIONAL groups , *NATURAL products , *BIOCHEMICAL substrates , *AMIDES - Abstract
A metal-free photoinduced alkynylation of carbamoyl radicals with hypervalent iodine(III) reagents for a facile synthesis of alkynyl amides is described. This protocol features good functional group tolerance and a broad substrate scope for direct synthesis of alkynyl amide derivatives in good to excellent yields under mild and redox-neutral reaction conditions. The synthetic application is demonstrated by the late-stage installation of alkynyl amides into natural products and active pharmaceutical relevant molecules. The mechanistic studies indicated the simultaneous existence of photoredox catalytic and direct photoexcited processes, and the quantum yields confirmed the occurrence of the radical chain propagation process. [ABSTRACT FROM AUTHOR]
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- 2024
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20. Pd-catalyzed CO-free double carbonylation for the synthesis of 1,4-ketoesters with Mo(CO)6 as the carbonyl source.
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Guo, Wenting, Gong, Houhong, Yuan, Wei, Zhou, Hualan, Tao, Li, and Zhu, Jing
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FUNCTIONAL groups , *MOLECULES , *CARBONYLATION - Abstract
An unprecedented Pd-catalyzed CO-free double carbonylation using Mo(CO)6 as a safe carbonyl source for the efficient synthesis of 1,4-ketoesters in an atom- and step-economic manner has been developed. The current method features operational safety, a wide substrate range, good functional group compatibility and easy scale-up. The application of carbonylation using a safe carbonyl source for the synthesis of biologically and synthetically useful carbonyl-containing molecules is underway in our lab. [ABSTRACT FROM AUTHOR]
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- 2024
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21. Synthesis of polysubstituted pyridazines via Cu-mediated C(sp3)–C(sp3) coupling/annulation of saturated ketones with acylhydrazones.
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Zhou, Honggui, Li, Zhefeng, Chen, Juehong, Zhou, Si, Wang, Xinyu, Zhang, Linwei, Chen, Jiuxi, and Lv, Ningning
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KETONES , *FUNCTIONAL groups , *CHEMOSELECTIVITY , *ANNULATION , *DERIVATIZATION , *PYRIDAZINES - Abstract
Pyridazine is a significant skeleton that widely exists in drugs and bioactive molecules. We herein describe expeditious approaches to access polysubstituted pyridazines from readily accessible unactivated ketones and acylhydrazones via Cu-promoted C(sp3)–C(sp3) coupling/cyclization sequences in a single-step fashion. Notably, the disparate 3,4,6-trisubstituted pyridazines and 3,5-disubstituted pyridazines could be obtained by tailoring the ketone's structure and reaction conditions. These transformations feature good functional group compatibility, excellent step-economy, and chemoselectivity. The potential synthetic utility of these conversions is illustrated by scale-up reactions and late-stage derivatizations of the as-prepared pyridazine products. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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22. 4,7-Substituted 1,10-phenanthroline-2,9-dicarboxamides: photophysics of ligands and their complexes with the Eu-Gd-Tb triad.
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Avagyan, Nane A., Lemport, Pavel S., Polikovskiy, Trofim A., Tsorieva, Alisia V., Metlin, Mikhail T., Taydakov, Ilya V., Zonov, Roman V., Lyssenko, Konstantin A., Vokuev, Mikhail F., Rodin, Igor A., Tarasevich, Boris N., Ustynyuka, Yuri A., and Nenajdenko, Valentine G.
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RARE earth metals , *LUMINESCENCE quenching , *ENERGY transfer , *CHARGE transfer , *FUNCTIONAL groups - Abstract
The impact of substituents at the 4- and 7-positions of 1,10-phenanthroline-2,9-dicarboxamides on the photophysical properties of the ligands and their coordination compounds with the lanthanide triad--europium, gadolinium, and terbium--was analyzed. This study demonstrates how modification of the electronic nature of ligands through the incorporation of diverse functional groups affects the luminescence properties of their complexes. The introduction of various substituents leads to the appearance of intra-ligand or ligand-to-ligand charge transfer (CT) states. The highest luminescence efficiency was observed for LH·Eu(NO3)3 (Qin = 54.1% and QL = 9.6%), suggesting strong luminescence quenching of the CT state. It was found that a relatively low ΔE (-3000 cm-1) supports direct energy transfer from S1 to T1 bypassing the CT state, even though it is outside Reinhoudt's optimal range. The introduction of fluorines leads to the strongest luminescence quenching among all the substituents. [ABSTRACT FROM AUTHOR]
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- 2024
- Full Text
- View/download PDF
23. Palladium-catalyzed 1,1-aminoxylation of 3-butenoic acid with 2-alkynylanilines.
- Author
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Zhang, Jinhui, Mao, Lihua, Liu, Chao, Tan, Xiangwen, Wu, Jiahao, Wei, Xuefeng, Wu, Wanqing, and Jiang, Huanfeng
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ALKENES , *FUNCTIONAL groups , *INDOLE , *SKELETON , *ATOMS - Abstract
Herein, a palladium-catalyzed 1,1-aminoxylation of 3-butenoic acid and 2-alkynylanilines has been developed, achieving the installation of two distinct heteroatom motifs across an olefin skeleton. The strategy features a high step and atom economy and good functional group tolerance, which outlines an efficient approach for simultaneously building up γ-butylactone and indole skeletons. Notably, an external ligand, 2,9-dimethyl-1,10-phenanthroline, has been used to succeed in this protocol to effectively suppress the production of indole byproducts. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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24. The Staged Photocatalytic Reactor in the Removal of Acetaminophen: Aspects of Adsorption and Photocatalysis.
- Author
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Aguilar, Claudia, García, Mayra, Montalvo, Carlos, Anguebes, Francisco, Abatal, Mohamed, Cerón, Julia, Cerón, Rosa, Figueroa, Sandra, Ruiz, Alejandro, and Rangel, Marcela
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HYSTERESIS loop , *MASS transfer , *RAMAN spectroscopy , *LIQUID chromatography , *FUNCTIONAL groups - Abstract
The efficiency of a staged photocatalytic reactor prototype was evaluated on a semi‐pilot scale with the removal of acetaminophen, for which anatase particles were synthesized by Sol‐Gel and impregnated on rectangular plates of clay. X‐ray diffraction and Energy Dispersive X‐ray Fluorescence patterns show that the final composite is made up of Al2O3 (14 %), SiO2 (41 %), CaO (3 %) TiO2 (34 %), and Fe2O3 (7 %). The impregnation method favors the dispersion of Anatase on the surface of the adsorbent. TiO2‐Anatase/Clay, classified as a macro‐porous solid with H3‐type hysteresis loops by N2 physisorption. Adsorption processes are improved when using TiO2‐Anatase/Clay compared to using TiO2‐Anatase. The external mass transfer has a greater influence on the removal rate. The dimensionless parameters of the Biot number indicate there are no limitations due to the diffusive effect on the interior of the particle. The evaluation of the kinetic data under the Langmuir‐Hinshelwood equation shows a decrease in efficiency as the initial concentration increases. The acetaminophen molecule shows destabilization in the structure of the aromatic ring with a visible decrease in the signals of this functional group evaluated by High‐Performance Liquid Chromatography and Raman Spectroscopy. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
25. Higher phosphorus and water use efficiencies and leaf stoichiometry contribute to legume success in drylands.
- Author
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Acuña‐Acosta, Delia M., Castellanos, Alejandro E., Llano‐Sotelo, José M., Sardans, Jordi, Peñuelas, Josep, Romo‐Leon, José R., and Koch, George W.
- Subjects
- *
WATER efficiency , *PHOSPHORUS in water , *CLIMATE change models , *PHOTOSYNTHETIC rates , *FUNCTIONAL groups - Abstract
Legumes are essential plants in dryland ecosystems worldwide because they increase nitrogen availability, so their understanding is vital for improving knowledge and modelling in the face of climate change. This work studies the differences in resource use efficiency and their relationship with photosynthetic, photochemical, bioelemental, and stoichiometric traits of coexistent legumes and non‐legumes in a Sonoran Desert ecosystem. We found that legumes had higher photosynthetic rates, intrinsic and seasonal water use efficiency (WUE), phosphorus use efficiency (PPUE), and higher light utilisation mediated by chlorophyll content and active reaction centers, which may increase their photoprotection. Legumes can increase their WUE and PPUE with no changes in nitrogen use efficiency (PNUE). Consequently, observed trait relationships between studied traits in these legumes have significant differences with the non‐legume species in the study. Stoichiometry is helpful, in some cases, as an indicator of nutrient use efficiency and enables functional group differentiation. Our results strongly relate legumes' higher resource use efficiency with their success in dryland ecosystems. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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26. Enantioselective Arylation of Sulfenamides to Access Sulfilimines Enabled by Palladium Catalysis.
- Author
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Yuan, Yin, Han, Yidan, Zhang, Zhi‐kun, Sun, Shijin, Wu, Ke, Yang, Junfeng, and Zhang, Junliang
- Subjects
- *
ASYMMETRIC synthesis , *DENSITY functional theory , *DIAZONIUM compounds , *FUNCTIONAL groups , *ARYLATION - Abstract
Sulfur‐containing functional groups have garnered considerable attention due to their common occurrence in ligands, pharmaceuticals, and insecticides. Nevertheless, enantioselective synthesis of sulfilimines, particularly diaryl sulfilimines remains a challenging and persistent goal. Herein we report a highly enantio‐ and chemoselective cross–coupling of sulfenamides with aryl diazonium salt to construct diverse S(IV) stereocenters by Pd catalysis. Bisphosphine ligands bearing sulfinamide groups play a crucial role in achieving high reactivity and selectivity. This approach provides a general, modular and divergent framework for quickly synthesizing chiral sulfilimines and sulfoximines that are otherwise challenging to access. In addition, the origins of the high chemoselectivity and enantioselectivity were extensively investigated using density functional theory calculations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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27. Synthesis of Secondary Boronates via Deaminative Cross‐Coupling of Alkyl Nitroso Carbamates and Boronic Acids.
- Author
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Paul, Shashwati and Brown, M. Kevin
- Subjects
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FUNCTIONAL groups , *CARBAMATES , *AMINO acids , *LYSINE , *AMINES , *BORONIC acids - Abstract
A strategy for transition metal‐free cross‐coupling of alkyl nitroso‐carbamates and boronic acids is reported. The N‐nitroso carbamates are easily prepared from the corresponding amine in two simple steps. This method allows for the synthesis of a wide variety of secondary boronates, benzylic boronates and formal Csp3−Csp2 cross‐coupling products under operationally simple conditions. Functional group tolerance is also demonstrated and applied in the modification of lysine to make non‐canonical amino acids. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
28. The construction of novel pyrrole-4H-chromene-embedded vinyl sulfonyl fluorides via a three-component process.
- Author
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Ajisafe, Monday Peter, Fayad, Eman, Ali, Ola A. Abu, and Qin, Hua-Li
- Subjects
- *
PHARMACEUTICAL chemistry , *FUNCTIONAL groups , *FLUOROETHYLENE , *BIOCHEMICAL substrates , *PYRROLE derivatives , *FLUORIDES , *SULFONATES , *SULFONYL compounds - Abstract
A synthetic strategy involving salicylaldehyde, 2-chloroprop-2-ene-1-sulfonyl fluoride (CESF), and pyrrole has been developed to construct novel pyrrole-4H-chromene-embedded vinyl sulfonyl fluoride derivatives with exclusive regioselectivity. This method exhibits moderate to excellent yields (45–93%) and showcases a wide substrate scope with excellent functional group compatibility. Additionally, the resulting sulfonyl fluorides were further diversified via sulfur fluoride exchange (SuFEx) reactions to produce sulfonates and sulfonamides, which are valuable structural motifs in medicinal chemistry. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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29. Synthesis of tetralone and indanone derivatives via cascade reductive Friedel–Crafts alkylation/cyclization of keto acids/esters.
- Author
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Yadav, Naveen, Mahato, Rina, Khan, Jabir, Jaiswal, Harshit, and Hazra, Chinmoy Kumar
- Subjects
- *
KETONIC acids , *ALKYLATION , *ESTERS , *RING formation (Chemistry) , *FUNCTIONAL groups - Abstract
We disclose herein a metal-free cascade reductive Friedel–Crafts alkylation/cyclization of keto acids/esters for the synthesis of tetralones and indanones. Owing to the simple reaction conditions and setup, this protocol features broad substrate generality, facile scalability, and remarkable functional group tolerance, including the synthesis of bioactive molecule sertraline. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
30. Transition-metal free, radical oxidation of 1,6-enyne cyclopropanation: synthesis of aza-bicyclo[4.1.0]heptane derivatives.
- Author
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Meena, Shivam A., Thakur, Deepika, Nandy, Abhijit, Ranjan, Rahul, Rai, Anubhav, Banerjee, Shibdas, and Verma, Akhilesh K.
- Subjects
- *
CYCLOPROPANATION , *HEPTANE , *FUNCTIONAL groups , *BIOCHEMICAL substrates , *REAL-time control , *OXIDATION - Abstract
A straightforward transition-metal-free sustainable methodology for oxidative cyclopropanation of aza-1,6-enynes has been devised, enabling the synthesis of valuable, functionalized azabicyclo[4.1.0]heptane-2,4,5-triones, via four bond formation in a single step under mild conditions. Control experiments and real-time mass data monitoring using online ESI-MS spectroscopy support the pathway proposed for this reaction. The synthesized products have been utilized in diverse product transformations. Key advantages of this reaction include its operational ease, transition metal-free nature, rapid completion, and compatibility with a wide range of functional groups and substrates. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Advances and Prospects of Carbon Dots for High‐Performance Zinc‐Based Batteries.
- Author
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Zhang, Zekun, Zhou, Xuelian, Dong, Jia, Xue, Taotao, Di, Yingran, Li, Bin, Zhao, Ningning, Dai, Lei, Wang, Ling, and He, Zhangxing
- Subjects
- *
ENERGY conversion , *DENDRITIC crystals , *STRUCTURAL engineering , *FUNCTIONAL groups , *CATHODES - Abstract
Zinc‐based batteries are emerging as the most promising candidates for large‐scale energy storage devices due to their low cost, high safety, and long‐term storage. However, zinc‐based batteries encounter challenges stemming from undesirable side reactions and zinc dendrites on the anode, as well as dissolution on the cathode. Owing to their extremely small size, substantial surface functional groups, and adjustable structure, carbon dots (CDs) present considerable benefits in augmenting coulombic efficiency, expanding cycle life, and enhancing the rate functionality of zinc‐based batteries. Herein, this review delves into the surface modification and morphological regulation of batteries elements by CDs, CDs composites, and CDs derivatives. Moreover, it systematically encapsulates the application of CDs in zinc‐based batteries, underscoring the pivotal role of CDs in the advancement of electrode technology. Finally, the review highlights the impediments and proposes potential avenues for utilizing CDs in zinc‐based batteries. This review aims to facilitate the development of superior solutions and provide scientific insights into energy storage technologies. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. One‐Pot Three‐Component Construction of (Z)‐3‐Benzylidene‐2‐(quinolin‐8‐yl)isoindolin‐1‐ones Through C(sp2)−H Bond Activation Using Calcium Carbide as a Solid Alkyne Source.
- Author
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Wen, Fei, Zhang, Yonghe, Zhang, Zhenghua, Mu, Hongmei, Cheng, Liyan, Wang, Jin, He, Bihong, Li, Zheng, and Fu, Rugang
- Subjects
- *
CALCIUM carbide , *ANNULATION , *FUNCTIONAL groups , *BENZAMIDE - Abstract
A simple method for the synthesis of (Z)‐3‐benzylidene‐2‐(quinolin‐8‐yl)isoindolin‐1‐ones through C(sp2)−H bond activation, Sonogashira cross‐coupling and annulation tandem reactions using calcium carbide as a solid alkyne source, and benzamides as starting materials is described. The inexpensive and easy‐to‐handle calcium carbide is first employed as the coupling partner in non‐activated C(sp2)−H bond activation. The one‐pot three‐component reactions proceed efficiently with a broad range of substrates and good tolerance for a diversity of functional groups. The reaction routes can also be scaled up to gram scale. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Microwave‐Assisted Copper‐Catalyzed Synthesis of 1‐Aryl Benzotriazole 3‐Oxides.
- Author
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Desai, Bhargav, Bharodiya, Akshay, Koppolu, Mani Kanta, Bhukya, Hussain, Dholakiya, Bharatkumar, and Naveen, Togati
- Subjects
- *
BORONIC acids , *BENZOTRIAZOLE , *BIOCHEMICAL substrates , *FUNCTIONAL groups , *BENZOTRIAZOLE derivatives - Abstract
In this work, we present a copper‐catalyzed rapid and efficient method for cross‐coupling of N‐hydroxy benzotriazole with boronic acids under microwave irradiation for the synthesis of 1‐aryl benzotriazole 3‐oxides. This protocol tolerates a wide range of substituted boronic acids to provide the corresponding products in good to excellent yields. The features of this strategy include a broad substrate scope, high functional group tolerance, short reaction time, and good to excellent yields. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
34. Stereoselective synthesis of 3-sulfone sugars via cobalt catalysis.
- Author
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Xiong, Tao, Cao, Zhen, Gu, Jiarui, Wang, Nengzhong, Liu, Mingguo, and Yao, Hui
- Subjects
- *
GLYCALS , *SODIUM salts , *COBALT , *FUNCTIONAL groups , *ALLYLATION - Abstract
AbstractWe report herein the stereoselective synthesis of 3-sulfone sugars in good yields from glycals and sodium arylsulfinates. Various 3,4-
O -carbonate glycals were sulfonylated directly by a range of benzene- and naphthalene-sulfinic acid sodium salts catalyzed by cobalt species, demonstrating a broad substrate scope. The mechanism of cobalt-catalyzed decarboxylative allylation from the bottom face of the sugar ring due to the steric effect from the C3 group of glycals was proposed. Moroever, cobalt catalysis tends to favor branched allylation, resulting in excellent regioselectivity. This synthetic strategy features the green sulfone source, good functional group tolerance, exclusive regioselectivity, and excellent stereoselectivity. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
35. Effects of clean fracturing fluids on coal microstructure and coalbed gas adsorption.
- Author
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Zhang, Qian, Cai, Feng, Xie, Haotian, and Fang, Yu
- Subjects
- *
FRACTURING fluids , *GREENHOUSE gas mitigation , *GAS absorption & adsorption , *COALBED methane , *METHANE , *WATER salinization , *GREEN business , *COAL - Abstract
Nowadays, some fracking fluids can enable resourceful extraction of coalbed methane and reduce greenhouse gas emissions. However, their toxicity or corrosiveness will cause harm to downhole workers and pollute groundwater resources. Thus, five kinds of clean composite fracturing fluids were developed in this paper by using starch solution as the matrix and adding various preparations. The change rule of methane adsorption capacity by microstructure changes of coal samples was investigated systematically, and the optimal composite fracturing fluid was determined. The results showed that the new fracturing fluid increased the degree of aromatic ring condensation by 43.3% and the average pore size by 52.1%. Also, the adsorption constants of a value decreased by 11.6% and b value decreased by 23.9%, which can remarkably reduce the methane adsorption. The experimental results provide theoretical support for the clean production of coalbed methane. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. Theoretical and experimental investigation of the impact of oil functional groups on the performance of smart water in clay-rich sandstones.
- Author
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Kazemi, Alireza, Khezerloo-ye Aghdam, Saeed, and Ahmadi, Mohammad
- Subjects
- *
ELECTRIC double layer , *FUNCTIONAL groups , *PETROLEUM , *INTERFACIAL tension , *SANDSTONE - Abstract
This research investigated the effect of ion concentration on the performance of low salinity water under different conditions. First, the effect of injection water composition on interparticle forces in quartz-kaolinite, kaolinite-kaolinite, and quartz-oil complexes was tested and modeled. The study used two oil samples, one with a high total acid number (TAN) and the other with a low TAN. The results illustrated that reducing the concentration of divalent ions to 10 mM resulted in the electric double layer (EDL) around the clay and quartz particles and the high TAN oil droplets, expanding and intensifying the repulsive forces. Next, the study investigated the effect of injection water composition and formation oil type on wettability and oil/water interfacial tension (IFT). The results were consistent with the modeling of interparticle forces. Reducing the divalent cation concentration to 10 mM led to IFT reduction and wettability alteration in high TAN oil, but low TAN oil reacted less to this change, with the contact angle and IFT remaining almost constant. Sandpack flooding experiments demonstrated that reducing the concentration of divalent cations incremented the recovery factor (RF) in the presence of high TAN oil. However, the RF increment was minimal for the low TAN oil sample. Finally, different low salinity water scenarios were injected into sandpacks containing migrating fines. By comparing the results of high TAN oil and low TAN oil samples, the study observed that fine migration was more effective than wettability alteration and IFT reduction mechanisms for increasing the RF of sandstone reservoirs. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Conjugation of primary amine groups in targeted proteomics.
- Author
-
Cai, Yang
- Subjects
- *
FUNCTIONAL groups , *PEPTIDES , *COVALENT bonds , *PROTEOMICS , *MOIETIES (Chemistry) - Abstract
Primary amines, in the form of unmodified N‐terminus of peptide/protein and unmodified lysine residue, are perhaps the most important functional groups that can serve as the starting points in proteomic analysis, especially via mass spectrometry‐based approaches. A variety of multifunctional probes that conjugate primary amine groups through covalent bonds have been developed and employed to facilitate protein/protein complex characterization, including identification, quantification, structure and localization elucidation, protein–protein interaction investigation, and so forth. As an integral part of more accurate peptide quantification in targeted proteomics, isobaric stable isotope‐coded primary amine labeling approaches eventually facilitated protein/peptide characterization at the single‐cell level, paving the way for single‐cell proteomics. The development and advances in the field can be reviewed in terms of key components of a multifunctional probe: functional groups and chemistry for primary amine conjugation; hetero‐bifunctional moiety for separation/enrichment of conjugated protein/protein complex; and functionalized linker/spacer. Perspectives are primarily focused on optimizing primary amine conjugation under physiological conditions to improve characterization of native proteins, especially those associated with the surface of living cells/microorganisms. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. Enhanced UV Nonlinear Optical Properties in Layered Germanous Phosphites through Functional Group Sequential Construction.
- Author
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Tian, Yao, Zeng, Wei, Dong, Xuehua, Huang, Ling, Zhou, Yuqiao, Zeng, Hongmei, Lin, Zhien, and Zou, Guohong
- Subjects
- *
FUNCTIONAL groups , *OPTICAL properties , *FREQUENCY changers , *PHOSPHITES , *COHERENCE (Optics) , *NONLINEAR optical spectroscopy - Abstract
This study pioneers a novel strategy for synthesizing solar‐blind ultraviolet (UV) nonlinear optical (NLO) crystals through functional groups sequential construction, effectively addressing the inherent trade‐offs among broad transmittance, enhanced second‐harmonic generation (SHG), and optimal birefringence. We have developed two innovative van der Waals layered germanous phosphites: GeHPO3, the first Ge(II)‐based oxide NLO crystal which exhibits a black phosphorus‐like structure, and K(GeHPO3)2Br, distinguished by its exceptional birefringence and graphene‐like structure. Significantly, GeHPO3 exhibits a remarkable array of NLO properties, including the highest SHG coefficient recorded among all NLO crystals for phase‐matching and generating 266 nm coherent light via quadruple frequency conversion. It delivers a potent SHG intensity, surpassing KH2PO4 (KDP) by 10.3 times at 1064 nm and β‐BaB2O4 by 1.3 times at 532 nm, complemented by a distinct UV absorption edge at 211 nm and moderate birefringence of 0.062 at 546 nm. Comprehensive theoretical analysis links these exceptional characteristics to the unique NLO‐active GeO34− units and the distinctive, highly ordered layered structures. Our findings deliver essential experimental insights into the development of Ge(II)‐based optoelectronic materials and present a strategic blueprint for engineering structure‐driven functional materials with customized properties. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
39. Novel Synthetic Industrial Approach for Efficient Synthesis of Baclofen through C–C Bond Formation.
- Author
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Raut, Changdev, Qureshi, Shafiya Kausar, Kadam, Nitin, Mungase, Kailas, Marepu, Nagaraju, Jagtap, Ashutosh, and Ambhaikar, Narendra
- Subjects
- *
BACLOFEN , *SPASTICITY , *CHLOROACETIC acids , *FUNCTIONAL groups , *SUSTAINABLE chemistry - Abstract
Baclofen is an active pharmaceutical ingredient used for the treatment of muscle spasticity. We describe our efforts to develop a novel synthetic approach through C–C bond formation and a cost-effective route to baclofen. The synthesis involved a two-step approach through C–C bond formation using the extensively and commercially available starting material 4-chlorobenzyl cyanide with chloroacetic acid as a reagent in an aprotic solvent, followed by reduction of the nitrile functional group. The synthetic route to baclofen has been demonstrated to be commercially viable, cost-effective, and environmentally friendly. Execution of the developed process led to the isolation of (+)-baclofen in an overall yield of 60% at a multikilogram scale with >99.5% HPLC purity. This article also discusses the cost-effectiveness of the process, the impurity profiling, and the product quality. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Ag(I)-catalyzed asymmetric (2+4) annulation reaction of 5-alkenyl thiazolones: synthesis of enantioenriched spiro[cyclohexenamines-thiazolones].
- Author
-
Choudhary, Kavita, Deshpande, Akanksha Santosh, and Singh, Vinod K.
- Subjects
- *
ANNULATION , *RING formation (Chemistry) , *FUNCTIONAL groups , *ISOMERIZATION , *STEREOSELECTIVE reactions - Abstract
The first metal-catalyzed (2+4) annulation of 5-alkenyl thiazolones and α,α-dicyanoalkylidenes has been developed via vinylogous Michael/cyclization/isomerization reaction. This (2+4) annulation reaction is catalyzed by a chiral Ag-(R)-DTBM-SEGPHOS catalyst, delivering enantioenriched spiro[cyclohexenamines-thiazolone] having contiguous quaternary and tertiary stereocenters in good to excellent yield (up to 80%) and excellent stereoselectivities (up to 97% ee and >20 : 1 dr). This methodology has high functional group tolerance and produces a broad range of enantioenriched products under mild reaction conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. CuBr2-mediated dehydrogenative [4+2] annulation of 1-naphthyl-1,3-indandiones and alkenes.
- Author
-
Zhang, Xu, Chang, Mengfan, Ni, Tongtong, Liu, Shuhan, Li, Wenguang, and Xu, Xuefeng
- Subjects
- *
ALKENES , *COPPER catalysts , *ANNULATION , *FUNCTIONAL groups , *NITROALKENES , *MOLECULES - Abstract
Intermolecular annulation reactions of 1-naphthyl-1,3-indandiones with alkenes proceed efficiently in the presence of a copper catalyst to generate spirocarbocycle compounds. Various spirocyclic molecules bearing an all-carbon quaternary center could be obtained by this novel method with good yields, excellent regioselectivity, and good functional group tolerance. A radical mechanism is proposed based on the HRMS analysis results of control experiments. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. Visualization of lignification in flax stem cell walls with novel click-compatible monolignol analogs.
- Author
-
Lan Yao, Rui Wang, Chang Geun Yoo, Yuhang Zhang, Xianzhi Meng, Wei Liu, Ragauskas, Arthur J., and Haitao Yang
- Subjects
RENEWABLE natural resources ,PLANT cell walls ,CLICK chemistry ,FUNCTIONAL groups ,LIGNINS - Abstract
Introduction: As an essential part of plant cell walls, lignin provides mechanical support for plant growth, enhances water transport, and helps to defend against pathogens. As the most abundant natural aromatic-based renewable resource on earth, its biosynthesis has always been a research focus, and it is still currently under study. Methods: In this study, the p-coumaryl alcohol analog (H
ALK ) and the coniferyl alcohol analog (GALK ) containing an alkyne group at the ortho position were synthesized and applied to lignification in vivo and in vitro. The incorporation of these novel lignin monomers was observed via fluorescence imaging. Results and Discussion: It was found that the two monolignol analogs could be incorporated in dehydrogenated polymers (DHPs) in vitro and in flax cell walls in vivo. The results showed that as the cultivation time and precursor concentration varied, the deposition of H and G-type lignin exhibited differences in deposition mode. At the subcellular scale, the deposited lignin first appears in the cell corner and the middle lamella, and then gradually appears on the cell walls. Furthermore, lignin was also found in bast fiber. It was demonstrated that these new molecules could provide high-resolution localization of lignin during polymerization. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
43. Multivalent Cu sites synergistically adjust carbonaceous intermediates adsorption for electrocatalytic ethanol production.
- Author
-
Chen, Xiao, Jia, Shuaiqiang, Zhai, Jianxin, Jiao, Jiapeng, Dong, Mengke, Xue, Cheng, Deng, Ting, Cheng, Hailian, Xia, Zhanghui, Chen, Chunjun, Xing, Xueqing, Zeng, Jianrong, Wu, Haihong, He, Mingyuan, and Han, Buxing
- Subjects
COPPER ,FUNCTIONAL groups ,CATALYSTS ,HYDROCARBONS ,ETHYLENE ,ETHANOL - Abstract
Copper (Cu)-based catalysts show promise for electrocatalytic CO
2 reduction (CO2 RR) to multi-carbon alcohols, but thermodynamic constraints lead to competitive hydrocarbon (e.g., ethylene) production. Achieving selective ethanol production with high Faradaic efficiency (FE) and current density is still challenging. Here we show a multivalent Cu-based catalyst, Cu-2,3,7,8-tetraaminophenazine-1,4,6,9-tetraone (Cu-TAPT) with Cu2+ and Cu+ atomic ratio of about 1:2 for CO2 RR. Cu-TAPT exhibits an ethanol FE of 54.3 ± 3% at an industrial-scale current density of 429 mA cm−2 , with the ethanol-to-ethylene ratio reaching 3.14:1. Experimental and theoretical calculations collectively unveil that the catalyst is stable during CO2 RR, resulting from suitable coordination of the Cu2+ and Cu+ with the functional groups in TAPT. Additionally, mechanism studies show that the increased ethanol selectivity originates from synergy of multivalent Cu sites, which can promote asymmetric C–C coupling and adjust the adsorption strength of different carbonaceous intermediates, favoring hydroxy-containing C2 intermediate (*HCCHOH) formation and formation of ethanol. This study proposes a multivalent Cu-based catalyst (Cu-TAPT) for electrocatalytic CO2 RR, which promotes specific intermediate formation by the synergy of Cu2+ and Cu+ sites, thereby achieving a 54.3% Faradaic efficiency of ethanol at 429 mA cm−2 . [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
44. Fibre-specific mitochondrial protein abundance is linked to resting and post-training mitochondrial content in the muscle of men.
- Author
-
Reisman, Elizabeth G., Botella, Javier, Huang, Cheng, Schittenhelm, Ralf B., Stroud, David A., Granata, Cesare, Chandrasiri, Owala S., Ramm, Georg, Oorschot, Viola, Caruana, Nikeisha J., and Bishop, David J.
- Subjects
MITOCHONDRIAL proteins ,PHYSICAL activity ,FUNCTIONAL groups ,MITOCHONDRIA ,PROTEOMICS - Abstract
Analyses of mitochondrial adaptations in human skeletal muscle have mostly used whole-muscle samples, where results may be confounded by the presence of a mixture of type I and II muscle fibres. Using our adapted mass spectrometry-based proteomics workflow, we provide insights into fibre-specific mitochondrial differences in the human skeletal muscle of men before and after training. Our findings challenge previous conclusions regarding the extent of fibre-type-specific remodelling of the mitochondrial proteome and suggest that most baseline differences in mitochondrial protein abundances between fibre types reported by us, and others, might be due to differences in total mitochondrial content or a consequence of adaptations to habitual physical activity (or inactivity). Most training-induced changes in different mitochondrial functional groups, in both fibre types, were no longer significant in our study when normalised to changes in markers of mitochondrial content. Exercise alters the mitochondrial proteome, but little is known about changes in different fibre types. Here, the authors provide insight into fibre-specific mitochondrial differences before and after training using proteomics in human skeletal muscle. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Biochemical and functional groups characteristics of tea blends from Ficus capensis and Justicia secunda.
- Author
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Uchegbu, Nneka Nkechi, Fasuan, Temitope Omolayo, Onuoha, Nchekwube Love, and Adepeju, Adefisola Bola
- Subjects
ERYTHROCYTES ,HERBAL teas ,ANIMAL experimentation ,FACTORIAL experiment designs ,FUNCTIONAL beverages - Abstract
Tea is one of the most consumed drinks in the world, second only to water, and is renowned for its wide range of health benefits.This study examined the development of tea blends from blends of Ficus capensis, and Justicias ecunda leaves. Dried leaves of F. capensis and J. Secunda were milled, sieved, and processed into tea using a three-level factorial design. The process was modelled and optimized. The tea was evaluated for physicochemical, phenolic compounds profile, antioxidants, and functional groups using standard procedures. The blood-boosting potentials of the herbal tea blends were investigated through animal experiment and haematological evaluations were carried out on the fed animals. The results gave the optimal extracts blends of 48 g/100 g of F. capensis and 52 g/100 g of J. secunda. Antioxidants showed 2,2-diphenyl-1-picryl-hydrazl value of 6464.95 ± 1.97 µmol Trolox equivalents/100 g, ferric reducing power (40.13 ± 0.07 mmol Fe
2+ /100 g), and metal chelating (57.40 ± 0.62%). Physicochemical property showed total dissolved solids value of 6.51 ± 0.11 mg/g, *L (78.35 ± 0.42), *a (3.14 ± 0.09), and*b (13.57 ± 0.12). Phenolic compounds profile showed the presence of epicatechin (115.63 ± 0.052 mg/100 g), which have been associated with ability to improve healthy-living and lower the risk of some degenerative health issues. The in vivo results showed that developed tea was able to recover up to 95.28% of the packed cell volume, red blood cell (94.78%), and haemoglobin (97.52%), which compared well with the commercial product. The study showed the potential application of F. Capensis and J. Secunda leaves extracts in the formulation of functional beverage. The formulation procedures is scalable and has domestic and industrial applications. The tea blend could serve as a functional food ingredient and beverage to improve human health. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
46. Ultrathin (15 nm) Carbon Sheets with Surface Oxygen Functionalization for Efficient Pseudocapacitive Na‐ion Storage.
- Author
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Etacheri, Vinodkumar, Maça, Rudi Ruben, Avvaru, Venkata Sai, Hong, Chulgi Nathan, Alazemi, Abdullah, and Pol, Vilas G.
- Subjects
ART materials ,AMORPHOUS carbon ,FUNCTIONAL groups ,NANOSTRUCTURED materials ,SODIUM ions ,ELECTRIC batteries - Abstract
Disordered carbon is the state of the art anode material for Na‐ion batteries due to their increased interlayer spacing and good electronic conductivity. However, its practical application is hindered by average specific capacity, poor rate performance, low coulombic efficiency and limited cycling stability. Herein, we report the superior pseudocapacitance enhanced Na‐ion storage of in situ surface functionalized carbon nanosheets. Anodes composed of ultrathin (~15 nm) carbon nanosheets demonstrated excellent reversible specific capacity (375 mAh/g at 25 mA/g), rate performance (150 mAh/g at 2 A/g), long‐term cycling performance (1000 cycles at 1 A/g) and coulombic efficiency (~100 %). Considerably higher pseudocapacitance (up to ~78 %) is also identified in this case compared to amorphous carbon particles. Spectroscopic and electrochemical studies proved Na‐ion intercalation in to the disordered carbon and pseudocapacitive storage driven by oxygen‐containing surface functional groups. Outstanding electrochemical performance is credited to the synergy between diffusion limited intercalation and pseudocapacitive surface Na‐ion storage. The demonstrated synthetic method of in situ functionalized carbon nanosheets is inexpensive and scalable. The strategy of functional group and morphology induced pseudocapacitive Na‐ion storage offer new prospects to design high‐performance Na‐ion battery electrodes. [ABSTRACT FROM AUTHOR]
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- 2024
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47. Effect of functional groups of plasticizers on starch plasticization.
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Chen, Yanxue, Wang, Ziyi, Jia, Lexin, Niu, Chaodan, Hu, Ziyue, Wu, Chengyuan, Zhang, Siqun, Ren, Jie, Qin, Guoqiang, Zhang, Guanglei, and Yang, Jinhui
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RADIAL distribution function , *MOLECULAR dynamics , *AMIDES , *AMINO group , *ETHYLENE glycol - Abstract
To investigate the impact of plasticizer functional groups on starch plasticization, three distinct plasticizers were selected in this study: ethylene glycol (EG), ethylenediamine (EDA), and ethylenebisformamide (EBF). Three models of the plasticizer/starch system were constructed using molecular dynamics (MD) simulations, and the analysis encompassed the computation of mean square displacement (MSD), radial distribution function (RDF), and hydrogen bonding energy for each system. Additionally, the proportions of simulation were used to prepare thermoplastic starch films, which were subsequently subjected to examinations such as DSC, XRD, FT-IR, SEM, and mechanical property testing. Comparative analysis of the simulation data from the three systems and the properties of the manufactured thermoplastic starch (TPS) established that the diverse functional groups of plasticizers significantly influenced starch plasticization. In different plasticizer functional group types, it was observed that hydroxyl groups in EG and amino groups in EDA predominantly form hydrogen bonds with hydroxyl groups in starch molecular chain. In contrast, amide groups in EBF can establish hydrogen bonds not only with hydroxyl groups of starch but also with ether bonds on the starch main chain, thereby resulting in more effective starch plasticization. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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48. Integrating different facets of diversity into food web models: how adaptation among and within functional groups shape ecosystem functioning.
- Author
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Wojcik, Laurie Anne, Klauschies, Toni, Velzen, Ellen van, Guill, Christian, and Gaedke, Ursula
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FOOD chains , *BIOMASS , *FUNCTIONAL groups , *GENETIC variation , *SOCIAL interaction - Abstract
Adaptation of communities to environmental fluctuations can emerge from different facets of biodiversity, which may impact ecosystem functioning differently. Previous work in the field of biodiversity–ecosystem functioning (BEF) examined how ecosystem functions can be influenced by two sources of adaptive potential: sorting – i.e. changes in community composition due to fitness differences – can occur when multiple species or groups are present (richness), and trait adaptability – i.e. trait adjustments within species or functional groups – can emerge from genetic or phenotypic diversity. However, their effect is typically studied separately, and often in the context of only one trophic level. Therefore, we used a trait‐based, multispecies predator–prey model to investigate how sorting and trait adaptability, at one or two trophic levels, separately or jointly shape ecosystem functions and properties, such as total biomass, production, biomass‐weighted mean trait, relative top–down control and synchrony. We found that the adaptive potential emerging from any facet of diversity induced changes in trophic interactions, in turn affecting biomass distributions within and across trophic levels, dynamical behaviour, and synchrony of biomass dynamics within a trophic level. Particularly, sorting and trait adaptability could contribute to a similar degree and at a similar time to temporal changes in ecosystem functions, but their respective contribution depended on the speed of trait adaptation, the trait range between similar functional groups and trophic interactions. We thus suggest to consider multiple facets of diversity and their corresponding sources of adaptive potential to deepen our mechanistic understanding of BEF relationships, especially in the context of rapid biodiversity change. [ABSTRACT FROM AUTHOR]
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- 2024
- Full Text
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49. Plant functional group interactions intensify with warming in alpine grasslands.
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Jaroszynska, Francesca, Lie Olsen, Siri, Gya, Ragnhild, Klanderud, Kari, Telford, Richard, and Vandvik, Vigdis
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PLANT communities , *CLIMATE change , *PLANT size , *FUNCTIONAL groups , *SOCIAL interaction - Abstract
Plant–plant interactions regulate plant community structure and function. Shifts in these interactions due to global climate change, mediated through disproportional increases of certain species or functional groups, may strongly affect plant community properties. Still, we lack knowledge of community‐level effects of climate‐driven changes in biotic interactions. We examined plant community interactions by experimentally removing a dominant functional group, graminoids, in semi‐natural grasslands in Southern Norway. To test whether the effect of graminoid removal varied with climate, the experiment was replicated across broad‐scale temperature and precipitation gradients. To quantify community‐level interactions across sites, we tested for changes in the remaining vascular community (i.e. forbs) cover, richness, evenness, and functional traits reflecting leaf‐economic investment and plant size over five years. The effect of graminoid removal on forb community structure and functioning varied over time, and along the climate gradients. Forb cover increased in response to graminoid removal, especially at warmer sites. Species richness increased following removal irrespective of climate, whilst evenness increased under warmer and wetter conditions irrespective of removal. No climate or removal effect was found for species turnover. Functional trait responses varied along the precipitation gradient – compared to controls, forb mean SLA decreased in drier conditions after graminoid removal. Leaf thickness increased under cooler and drier conditions irrespective of removal. These community structure alterations demonstrate stronger competitive interactions between forbs and graminoids under warmer conditions, whilst functional trait responses indicate a facilitative effect of graminoids under drier conditions. This indicates that both competition and facilitation regulate plant communities, suggesting complexity when scaling from populations to communities. Finally, both temperature and precipitation determine the direction and intensity of biotic interactions, with ecosystem‐wide implications for forb persistence and ecosystem functioning under future climates. Further work is needed to generalise the role of changing interactions in mediating community responses to climate change. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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50. Effect of biochar structure on the selective adsorption of heavy components in bio‐oil.
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Zhu, Haonan, Yan, Shanshan, Wu, Yansheng, Xu, Hao, Chen, Haoran, Zhang, Hong, Guo, Xin, Hu, Xun, Zhang, Shu, and Gao, Wenran
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BIOCHAR , *POROSITY , *AROMATIC compounds , *ADSORPTION capacity , *FUNCTIONAL groups - Abstract
In this study, biochars with different structures were prepared through HNO3 oxidation and secondary pyrolysis to study the relationship between the structure of biochar and its selectivity for the adsorption of light and heavy aromatics in bio‐oil. The results showed that the adsorption rates of biochar with different structures ranged from 2.90 to 4.00 g bio‐oil per g biochar. The influence of pore structure was dominant, followed by the influence of O‐containing functional groups and the degree of graphitization. The higher the adsorption capacity of biochar for bio‐oil, the smaller the concentrations of the light aromatic model compounds in the absorbed bio‐oil (ABO). Among the five light aromatics, biochar has the best adsorption selectivity for dihydroxybiphenyl and the worst for eugenol and propyl phenol. This is attributed to the diphenyl ring structure of dihydroxybiphenyl, which makes it more susceptible to adsorption, and other light model compounds only have one benzene ring. In summary, biochar demonstrates better adsorption selectivity for heavy aromatics than light aromatics. The more developed the pore structure is, the more enriched O‐containing functional groups are, and the higher the graphitization degree of biochar is, the better the selective adsorption of aromatic compounds in bio‐oil. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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