486 results on '"Onium compound"'
Search Results
2. Asymmetric Hydrocyanation of N ‐Phosphinoyl Aldimines with Acetone Cyanohydrin by Cooperative Lewis Acid/Onium Salt/Brønsted Base Catalysis
- Author
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Marvin Titze, Thorsten Junge, Wolfgang Frey, and René Peters
- Subjects
chemistry.chemical_classification ,Aldimine ,Chemistry ,Organic Chemistry ,Onium compound ,Catalysis ,Amino acid ,Inorganic Chemistry ,chemistry.chemical_compound ,Polymer chemistry ,Hydrocyanation ,Lewis acids and bases ,Physical and Theoretical Chemistry ,Brønsted–Lowry acid–base theory ,Acetone cyanohydrin - Published
- 2021
3. Enhanced catalytic activity of new di-site onium salt in the kinetics of α-Tolunitrile monoalkylation
- Author
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P.A. Vivekanand, V. Thiruvengadam, T.K. Fayaz, S. Harikumar, V. Shanmugam, and P. Kamaraj
- Subjects
010302 applied physics ,chemistry.chemical_classification ,Base (chemistry) ,Kinetics ,Inorganic chemistry ,Onium compound ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Chloride ,Catalysis ,chemistry.chemical_compound ,chemistry ,0103 physical sciences ,medicine ,Catalytic efficiency ,0210 nano-technology ,Benzene ,Phase-transfer catalyst ,medicine.drug - Abstract
In this study, we investigate in detail the catalytic efficiency of 1,4-bis-(ethylmethyleneammounium chloride)-2,5- dimethoxy benzene, BEMACDB (multi-site phase transfer catalyst) by observing the pseudo-first order kinetics of mono-alkylation of α-Tolunitrile (ATN). The formation of product was monitored by GC. The comparative study of catalytic efficiency of the new catalysts with single-site salts reveals higher catalytic activity for new catalysts under varying experimental conditions ([BEMACDB], [Base], [ATN], Stirring Speed and Temperature). By understanding the kinetics of mono-alkyaltion, we further establish the experimental parameters that influence reaction conditions. With the support of kinetic data we establish the suitable mechanism for monoalklation of ATN. The catalyst shows consistent catalytic activity in the C-alkylation of ATN in different experimental conditions.
- Published
- 2021
4. The use of a diammonium salt in the synthesis of organic carbonates from epoxides and CO2: promoting effect of support
- Author
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Sergey E. Lyubimov, Ashot V. Arzumanyan, Biswajit Chowdhury, Aziz M. Muzafarov, A. A. Zvinchuk, and Vadim A. Davankov
- Subjects
chemistry.chemical_classification ,chemistry ,010405 organic chemistry ,Scientific method ,Salt (chemistry) ,Organic chemistry ,Onium compound ,General Chemistry ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Catalysis - Abstract
Onium salt, N1, N1, N1, N5, N5, N5-hexaethylpentane-1,5-diammonium dibromide, was used as a catalyst for the addition of CO2 to epoxides. An influence of insoluble supports on the rate of the process as well as possibility of recycling of the catalytic system are described. In addition, the effects of temperature and CO2 pressure on the yields of products are discussed.
- Published
- 2020
5. Hydrogen‐Bonding Catalysis of Alkyl‐Onium Salts
- Author
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Takumi Nakamura, Ken Okuno, Seiji Shirakawa, and Ryuichi Nishiyori
- Subjects
chemistry.chemical_classification ,010405 organic chemistry ,Sulfonium ,Organic Chemistry ,Salt (chemistry) ,Onium compound ,General Chemistry ,Onium ,010402 general chemistry ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,chemistry ,Organocatalysis ,Organic chemistry ,Phosphonium ,Alkyl - Abstract
The synthetic utility of alkyl-onium salt compounds is widely recognized in the field of organic chemistry. Among the wide variety of onium salts, quaternary ammonium, phosphonium, and tertiary sulfonium salts have been the most useful compounds in organic syntheses. These compounds have been very useful reagents in the construction of organic building blocks. In addition, onium salts are known as reliable catalysts, which are used to promote important organic transformations by serving as phase-transfer and ion-pair catalysts through the activation of nucleophiles. Although phase-transfer catalysis is a major direction for onium salt catalysis, hydrogen-bonding catalysis of alkyl-onium salts, which is promoted via the activation of electrophiles, has recently become a relevant topic in the field of onium salt chemistry. This Minireview introduces new possibilities and future directions for alkyl-onium salt chemistry based on its use in hydrogen-bonding catalysis and on its overall utility.
- Published
- 2020
6. An efficient PyAOP-based C4-amination method for direct access of oxidized 5MedC derivatives
- Author
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Wei-Jie Chen, Rui Kong, Shan-Shan Gong, Qi Sun, Xiu-An Zheng, and Hua-Shan Huang
- Subjects
Pyrimidine ,010405 organic chemistry ,Organic Chemistry ,Onium compound ,Onium ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Combinatorial chemistry ,0104 chemical sciences ,Nucleobase ,chemistry.chemical_compound ,Aminolysis ,chemistry ,Reagent ,Drug Discovery ,Ribose ,Amination - Abstract
In the past decade, synthetic oxidized 5-MedC nucleosides and their derivatives have become essential tools for epigenetic research. The low efficacy of both conventional and newly reported BOP methods on C4-amination of these specific oxidized 5-MedU substrates urged us to systematically investigate how the nature of onium salt-based coupling reagents affects the C4-amination of pyrimidine nucleobases and lead us to the findings that different onium coupling reagents result in the formation of distinctive activation intermediates and PyAOP is much more potent than BOP in both activation and aminolysis steps. Direct amination without the need of ribose protection, ultrafast activation, tolerance to aqueous N-nucleophiles, and excellent yields for diverse oxidized 5MedC derivatives are the advantages of this PyAOP-based C4-amination method.
- Published
- 2018
7. Photochemical fate of sulfonium photoacid generator cations under photolithography relevant UV irradiation
- Author
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Leif Abrell, Jim A. Field, Rodrigo Paniego, Reyes Sierra-Alvarez, Jon Chorover, Richard D. Pepel, Xi-Zhi Niu, and A. Eduardo Sáez
- Subjects
Reaction mechanism ,Sulfonium ,General Chemical Engineering ,Photodissociation ,General Physics and Astronomy ,Aromaticity ,Onium compound ,02 engineering and technology ,General Chemistry ,Onium ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Homolysis ,chemistry.chemical_compound ,chemistry ,Irradiation ,0210 nano-technology - Abstract
Onium salts, widely used as photoacid generators (PAGs) in the semiconductor industry, are receiving increased regulatory scrutiny due to their potential hazardous properties. Evaluating the environmental impacts of these chemicals requires knowledge of the fate of the onium species during photolithography steps, which remains unclear for many PAGs. The current study investigated the fate of four representative sulfonium PAGs using an irradiation setup simulating industrial photolithography. The photolytic fate for three of the four selected onium cations is reported for the first time. All onium compounds reacted rapidly under 254 nm irradiation, and their half-lives ranged from 51 to 214 s with high quantum yields (0.23−0.85). Multiple highly aromatic and hydrophobic photoproducts were characterized using HPLC-DAD and GC-MS; eight PAG photoproducts were identified for the first time. Authentic commercial standards of some of the photoproducts were available, enabling quantitative estimates of recoveries. The molar recovery of aromatic rings based on these quantified photoproducts was in the range of 4.9–71.4 %. A homolytic reaction mechanisms is proposed and discussed. The results provide insight on the potential environmental impact pertinent to the use of PAGs, e.g., prediction of residual onium levels and the identity of photoproducts in effluents from semiconductor fabrication facilities.
- Published
- 2021
8. Driving Force Dependence of Electron Transfer from Electronically Excited [Ir(COD)(μ-Me2pz)]2 to Photo-Acid Generators
- Author
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James W. Thackeray, Wesley Sattler, James F. Cameron, Suzanne Coley, Astrid M. Müller, Harry B. Gray, Jay R. Winkler, Paul J. LaBeaume, and Aaron A. Rachford
- Subjects
Analytical chemistry ,Onium compound ,02 engineering and technology ,Onium ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Electron transfer ,Reaction rate constant ,chemistry ,Excited state ,Physical and Theoretical Chemistry ,Diffusion limit ,0210 nano-technology ,Acetonitrile ,Electrochemical window - Abstract
We report the rates of electron transfer (ET) reactions of electronically excited [Ir(COD)(μ-Me2pz)]2 with onium salt photoacid generators (PAGs). The reduction potentials of the PAGs span a large electrochemical window that allows determination of the driving force dependence of the ET reactions. Rate constants of ET from electronically excited [Ir(COD)(μ-Me2pz)]2 to onium PAGs are determined by the reaction driving force until the diffusion limit in acetonitrile is reached.
- Published
- 2017
9. The evaluations of 99m Tc cyclopentadienyl tricarbonyl triphenyl phosphonium cation for multidrug resistance
- Author
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Ying Zhang, Hongmei Jia, Xiaoyan Li, Shuting Chen, and Jie Lu
- Subjects
0301 basic medicine ,Biodistribution ,Stereochemistry ,Clinical Biochemistry ,Pharmaceutical Science ,01 natural sciences ,Biochemistry ,03 medical and health sciences ,Cyclopentadienyl complex ,In vivo ,Drug Discovery ,skin and connective tissue diseases ,Molecular Biology ,P-glycoprotein ,biology ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,Onium compound ,In vitro ,0104 chemical sciences ,Multiple drug resistance ,030104 developmental biology ,Cell culture ,biology.protein ,Molecular Medicine - Abstract
A triphenylphosphonium cation, [99mTc]Technetium cyclopentadienyltricarbonyl-6-hexanoyl-triphenylphosphonium cation ([99mTc]3) was prepared to target multidrug resistance (MDR). The radiotracer was evaluated in the MDR-negative MCF-7 and MDR-positive MCF-7/ADR cell lines in vitro, as well as animal models in vivo. [99mTc]3 was proofed to be a substrate of P-glycoprotein and multidrug resistant protein 1, and showed a higher accumulation in the MDR-negative MCF-7 cells compared to 99mTc-sestamibi in vitro. The MCF-7 tumor-to-MCF-7/ADR tumor ratio of [99mTc]3 was ∼3 at 1hp.i. in the biodistribution study. These results demonstrated the capability of the radiotracer to detect multidrug resistance in tumor cells.
- Published
- 2017
10. Switchable catalytic processes involving the copolymerization of epoxides and carbon dioxide for the preparation of block polymers
- Author
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Donald J. Darensbourg
- Subjects
chemistry.chemical_classification ,Primary (chemistry) ,010405 organic chemistry ,Epoxide ,Onium compound ,Polymer ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,Monomer ,chemistry ,visual_art ,Polymer chemistry ,visual_art.visual_art_medium ,Copolymer ,Organic chemistry ,Polycarbonate - Abstract
This minireview's primary focus is to review recent studies from my research program on the development of one-pot, two-step processes for the synthesis of di- and tri-block polymers. In all of these prepared polymeric materials at least one component is a polycarbonate derived from the copolymerization of CO2 and epoxides. Synthetic methodology for the preparation of polycarbonate diols of well-defined molecular weights with narrow polydispersities are presented using (salen)CoX/onium salt catalyst systems. These polyols were subsequently utilized in the synthesis of di-and tri-block polylactide/polycarbonate or polyphosphoester/polycarbonate polymers employing organocatalysts. In addition, the introduction of these polyols to a second epoxide/CO2 copolymerization process provided block polycarbonate materials. Of particular interest, the first or second epoxide monomer incorporated into the copolymer can possess vinyl groups for postpolymerization modification by thiol–ene chemistry. These degradable polymeric materials have significant potential for use in biomedical applications.
- Published
- 2017
11. Cationic Organic Catalysts or Ligands in Concert with Metal Catalysts
- Author
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Takashi Ooi and Kohsuke Ohmatsu
- Subjects
Supramolecular chemistry ,Stereoisomerism ,Onium compound ,General Chemistry ,Onium ,Ligands ,010402 general chemistry ,01 natural sciences ,Combinatorial chemistry ,Carbon ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Nucleophile ,chemistry ,Coordination Complexes ,Metals ,Cations ,Electrophile ,Reactivity (chemistry) ,Bifunctional ,Schiff Bases ,Lewis Acids - Abstract
Cooperative dual catalysis and bifunctional catalysis have emerged as reliable strategies for the development of hitherto difficult asymmetric transformations because they could deliver new reactivity and selectivity, and allow for the employment of substrates not amenable to reaction systems relying on a single, monofunctional catalysts. Furthermore, these modes of catalysis often improve yields and stereoselectivities via the precise recognition and simultaneous activation of nucleophiles and electrophiles. Efforts towards utilizing chiral cationic organic catalysts for asymmetric cooperative catalysis with metal complexes have provided a unique platform to address the challenging issues associated with reaction development. Chiral onium ions, such as tetraalkylammonium, guanidinium, and azolium ions, are employed mainly to control the reactivity and stereochemistry of anionic intermediates through electrostatic and hydrogen-bonding interactions. Metal complexes complement the synergy of the catalysis by activating the substrates via the formation of electrophilic π-allyl complexes, Lewis acid-base adducts, nucleophilic ate complexes, etc. The electrostatic interactions between cations and anions also offer a means to construct complex molecular assemblies, and, thus, onium ions are useful not only for controlling pairing with anionic species, but also for the design of supramolecular catalysts. The combination of onium ions and metal complexes leads to the introduction of novel concepts and powerful strategies for the development of catalysts and chemical transformations.
- Published
- 2019
12. Onium Ion-assisted Organic Reactions Through Cation–π Interactions
- Author
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Shinji Yamada
- Subjects
chemistry.chemical_compound ,chemistry ,Organic reaction ,Computational chemistry ,Cation π ,Organic synthesis ,Onium compound ,Interaction energy ,Onium ,Ion - Abstract
The cation–π interaction is an attractive noncovalent interaction between a cation and a π-face. Owing to the stronger interaction energy than those of the other π interactions, such as π–π and CH–π interactions, the cation–π interaction has recently been recognized as a new tool for controlling the regio- and stereoselectivities in various types of organic reactions. This chapter attempts to cover a variety of organic reactions assisted by interactions between unreactive onium ions and π-faces, which will provide comprehensive knowledge on the role of cation–π interactions in organic synthesis.
- Published
- 2019
13. Ionic liquids as novel media for electrophilic/onium ion chemistry and metal-mediated reactions: a progress summary
- Author
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Kenneth K. Laali
- Subjects
010405 organic chemistry ,Chemistry ,Organic Chemistry ,Inorganic chemistry ,Onium compound ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Metal ,lcsh:QD241-441 ,chemistry.chemical_compound ,lcsh:Organic chemistry ,visual_art ,Ionic liquid ,Electrophile ,visual_art.visual_art_medium ,Organic chemistry - Abstract
The account presented here summarizes progress from the author's laboratory during the past 15 years on the application of room temperature ionic liquids (RTILs) as solvents and catalysts in electrophilic/onium ion chemistry as well as in metal-mediated bond forming reactions.
- Published
- 2016
14. Water Soluble Onium Salt Type Photo Amphoteric Compound Generators
- Author
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Daiki Kashiwai, Shigeru Takahara, Takuma Sawada, Yuiichi Kaneko, and Yusuke Sato
- Subjects
Polymers and Plastics ,Chemistry ,Organic Chemistry ,Onium compound ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Water soluble ,Polymer chemistry ,Materials Chemistry ,Organic chemistry ,0210 nano-technology - Published
- 2016
15. Relayed Regioselective Alkynylation/Olefination of Unsymmetrical Cyclic Diaryliodonium Species Catalyzed by Cu and Pd: Affording Fluorescent Cytotoxic Benzoxazoles
- Author
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Bingling Luo, Daqian Zhu, Wenhua Lu, Haiwen Wang, Shijun Wen, Peng Huang, Panpan Liu, and Yumin Hu
- Subjects
Benzoxazoles ,Molecular Structure ,Stereochemistry ,Organic Chemistry ,Synthon ,chemistry.chemical_element ,Regioselectivity ,Stereoisomerism ,Onium compound ,General Chemistry ,Ring (chemistry) ,Catalysis ,chemistry.chemical_compound ,Onium Compounds ,chemistry ,Copper ,Palladium ,Fluorescent Dyes ,Oxazole - Abstract
Although cyclic diaryliodonium species have the potential to act as valuable synthons for cascade transformations, they still remain largely unexplored. The regioselectivity associated with unsymmetrical cyclic diaryliodonium species has previously been known to pose a challenge. A regioselective relayed alkynylation and olefination of unsymmetrical cyclic diaryliodonium species has been achieved by installation of a directing amido group. These relayed transformations were delayed until an oxazole ring had formed, delivering a series of unique fluorescent benzoxazoles. Moreover, some of these synthetic benzoxazoles showed apparent inhibitory activity against malignant cancer cells. Further confocal visualization revealed that benzoxazoles targeted cell nuclei. These findings might provide a novel structural scaffold to develop desirable anticancer agents.
- Published
- 2015
16. Generation of ferrocenylvinyl cation CpFeC 5 H 4 –C + =CH 2 by protonation of ferrocenylacetylene with Nafion and its reactions with SMe 2 and PPh 3 in scCO 2 giving onium salts
- Author
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Fedor M. Dolgushin, Dmitrii Yu. Antonov, Lev N. Nikitin, Alexei R. Khokhlov, Ivan S. Chaschin, Ivan A. Godovikov, and Ol’ga A. Kizas
- Subjects
Tetrafluoroborate ,010405 organic chemistry ,Protonation ,Onium compound ,General Chemistry ,Nuclear magnetic resonance spectroscopy ,Onium ,010402 general chemistry ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Nafion ,Polymer chemistry ,Superacid - Abstract
Cation CpFeC5H4–C+=CH2 was obtained by protonation of FcC CH with Nafion superacid in DMF or scCO2 and characterized by NMR spectroscopy. The protonation in the presence of SMe2 or PPh3 affords new onium derivatives, which were isolated as the tetrafluoroborate salts.
- Published
- 2017
17. Asymmetric Carboxycyanation of Aldehydes by Cooperative AlF/Onium Salt Catalysts: from Cyanoformate to KCN as Cyanide Source
- Author
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Florian Broghammer, Johannes Kästner, Jan Meisner, René Peters, Delphine Garnier, Sonia Álvarez-Barcia, Wolfgang Frey, Julian Klepp, and Daniel Brodbeck
- Subjects
chemistry.chemical_classification ,010405 organic chemistry ,Chemistry ,Cyanide ,Organic Chemistry ,Onium compound ,General Chemistry ,Onium ,010402 general chemistry ,01 natural sciences ,Combinatorial chemistry ,Aldehyde ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Reagent ,Moiety ,Bifunctional - Abstract
Asymmetric 1,2-additions of cyanide yield enantioenriched cyanohydrins as versatile chiral building blocks. Next to HCN, volatile organic cyanide sources are usually used. Among them, cyanoformates are more attractive on technical scale than TMSCN for cost reasons, but catalytic productivity is usually lower. Here, the development of a new strategy for cyanations is described, in which this activity disadvantage is overcome. A Lewis acidic Al center cooperates with an aprotic onium moiety within a remarkably robust bifunctional Al-F-salen complex. This allowed for unprecedented turnover numbers of up to 104 . DFT studies suggest an unexpected unique trimolecular pathway in which the ammonium bound cyanide attacks the aldehyde, which itself is activated by the carbonyl group of the cyanoformate binding to the Al center. In addition, a novel practical carboxycyanation method was developed that makes use of KCN as the sole cyanide source. The use of a pyrocarbonate as carboxylating reagent provided the best results.
- Published
- 2018
18. Ionic Liquids as Novel Media and Catalysts for Electrophilic/Onium Ion Chemistry and Metal-Mediated Reactions
- Author
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Kenneth K. Laali and Gopalakrishnan Aridoss
- Subjects
Metal ,Acylation ,chemistry.chemical_compound ,Chemistry ,visual_art ,Nitration ,Ionic liquid ,Electrophile ,visual_art.visual_art_medium ,Organic chemistry ,Onium compound ,Alkylation ,Catalysis - Abstract
This chapter summarizes recent progress in the application of room temperature ionic liquids as solvents and catalysts in electrophilic/onium ion chemistry, in metal-mediated bond-forming reactions, and in selected other key reactions.
- Published
- 2018
19. An Investigation of the Pathways for Oxygen/Sulfur Scramblings during the Copolymerization of Carbon Disulfide and Oxetane
- Author
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Ming Luo, Xing-Hong Zhang, and Donald J. Darensbourg
- Subjects
Carbon disulfide ,Polymers and Plastics ,Organic Chemistry ,chemistry.chemical_element ,Onium compound ,Onium ,Oxetane ,Photochemistry ,Sulfur ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,Copolymer ,Propylene oxide - Abstract
The catalytic coupling of oxetane, the symmetric isomer of propylene oxide, with carbon disulfide has been investigated utilizing (salen)CrCl in the presence of various onium salts. Oxygen and sulfur atom exchange was observed in both the polymeric and cyclic carbonate products. The coupling of oxetane and CS2 was selective for copolymer formation over a wide range of reaction conditions. Five different polymer linkages and two cyclic products were determined by 1H and 13C NMR spectroscopy, and these results were consistent with in situ infrared spectroscopic monitoring of the process. The major cyclic product produced in the coupling process was trimethylene trithiocarbonate, which was isolated and characterized by single crystal X-ray crystallography. Upon increasing the CS2/oxetane feed ratio, a decrease in the O/S scrambling occurred. The reaction temperature had the most significant effect on the O/S exchange process, increasing exchange with increasing temperature. The presence of the onium salt ini...
- Published
- 2015
20. Efficient visible photoinitiator containing linked dye-coinitiator and iodonium salt for free radical polymerization
- Author
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Xuying Nan, Yi Huang, Qinguo Fan, and Jianzhong Shao
- Subjects
General Chemical Engineering ,Organic Chemistry ,Radical polymerization ,Electron donor ,Onium compound ,Chromophore ,Photochemistry ,Photoinduced electron transfer ,Surfaces, Coatings and Films ,chemistry.chemical_compound ,Photopolymer ,chemistry ,Polymer chemistry ,Materials Chemistry ,Methylene ,Photoinitiator - Abstract
Dye-linked initiators consisting of erythrosine B as a chromophore and ethyl 4-dimethylaminobenzoate as an electron donor linked by a different number of methylene units were prepared to achieve efficient photoinitiators of free radical polymerization in a visible-light region. The relative photoinitiating efficiencies of novel photoinitiators in photopolymerization of acrylates were evaluated. The results showed that the photoinitiating system composed of the dye-linked dyad with short methylene unit chain and diphenyliodonium salt exhibited a remarkable increase in the photoinitiation ability compared to unlinked three-component system. The enhancement mechanism aroused by the onium salt was investigated. These results showed that the excellent initiating efficiency of this system could be attributed to the favorable intramolecular photoinduced electron transfer and the close distance between reaction components caused by electrostatic interactions. This result demonstrated the importance and potential of the linked photoinitiator in the design of new efficient photoinitiators.
- Published
- 2015
21. Complex formation of sulfur(IV) oxide with ethylenediamine and its derivatives in water
- Author
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R. E. Khoma
- Subjects
Piperazine ,chemistry.chemical_compound ,Aqueous solution ,chemistry ,Ethylenediamines ,Potentiometric titration ,Inorganic chemistry ,chemistry.chemical_element ,Onium compound ,Ethylenediamine ,General Chemistry ,Onium ,Sulfur - Abstract
Data of potentiometric, redox, and conductometric studies of interactions in the sulfur(IV) oxide-ethylenediamine (or its analogs)-water systems, being in fair agreement, have showed the formation of onium sulfites, hydrosulfites, and pyrosulfites. The absorbance capacity of aqueous solutions of ethylenediamines with respect to sulfur dioxide depends on the amino groups amount. Ion and molecular compositions of the studied solutions have been computed, and the relative stability of onium sulfites of ethylenediamine and piperazine has been estimated.
- Published
- 2015
22. Energy decomposition analysis of cation-π, metal ion-lone pair, hydrogen bonded, charge-assisted hydrogen bonded, and π-π interactions
- Author
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G. Gayatri, Hemant Kumar Srivastava, Bhaskar Sharma, and Garikapati Narahari Sastry
- Subjects
chemistry.chemical_classification ,Hydrogen ,Chemistry ,Hydrogen bond ,chemistry.chemical_element ,Onium compound ,General Chemistry ,Interaction energy ,Metal ,Computational Mathematics ,Crystallography ,Computational chemistry ,visual_art ,visual_art.visual_art_medium ,Non-covalent interactions ,Polarization (electrochemistry) ,Lone pair - Abstract
This study probes the nature of noncovalent interactions, such as cation-π, metal ion-lone pair (M-LP), hydrogen bonding (HB), charge-assisted hydrogen bonding (CAHB), and π-π interactions, using energy decomposition schemes-density functional theory (DFT)-symmetry-adapted perturbation theory and reduced variational space. Among cation-π complexes, the polarization and electrostatic components are the major contributors to the interaction energy (IE) for metal ion-π complexes, while for onium ion-π complexes (NH4+, PH4+, OH3+, and SH3+) the dispersion component is prominent. For M-LP complexes, the electrostatic component contributes more to the IE except the dicationic metal ion complexes with H2 S and PH3 where the polarization component dominates. Although electrostatic component dominates for the HB and CAHB complexes, dispersion is predominant in π-π complexes.
- Published
- 2015
23. Estimating the binding ability of onium ions with CO2 and π systems: a computational investigation
- Author
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M. Althaf Hussain, A. Subha Mahadevi, and G. Narahari Sastry
- Subjects
chemistry.chemical_classification ,Chemistry ,Computational chemistry ,Hydrogen bond ,Atoms in molecules ,Binding energy ,General Physics and Astronomy ,Non-covalent interactions ,Density functional theory ,Onium compound ,Physical and Theoretical Chemistry ,Onium ,Ion - Abstract
Density functional theory (DFT) calculations have been employed on 165 complexes of onium ions (NH4+, PH4+, OH3+, SH3+) and methylated onium ions with CO2, aromatic (C6H6) and heteroaromatic (C5H5X, X = N, P; C4H5Y, Y = N, P; C4H4Z, Z = O, S) systems. The stability of CO2⋯onium, CO2⋯π and onium⋯π complexes was shown to be mediated through various noncovalent interactions such as hydrogen bonding, NH–π, PH–π, OH–π, SH–π, CH–π and π–π. We have discussed 17 complexes wherein the proton transfer occurs between the onium ion and the heteroaromatic system. The binding energy is found to decrease with increasing methyl substitution of the complexes containing onium ions. Binding energy components of all the noncovalent complexes were explored using localized molecular orbital energy decomposition analysis (LMO-EDA). The CO2⋯π complexes were primarily stabilized by the dispersion term followed by contributions from electrostatic and polarization components. In general, for onium ion complexes with CO2 or π systems, the electrostatic and polarization terms primarily contribute to stabilize the complex. As the number of methyl groups increases on the onium ion, the dispersion term is seen to have a key role in the stabilization of the complex. Quantum theory of atoms in molecules (QTAIM) analysis and charges based on natural population analysis (NPA) in various complexes have also been reported in order to determine the nature of noncovalent interactions in different complexes.
- Published
- 2015
24. Hexamethylene diisocyanate as an electrolyte additive for high-energy density lithium ion batteries
- Author
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Yinping Qin, Zhe Peng, Changjin Wan, Jingjing Zhou, Deyu Wang, and Yang Liu
- Subjects
Renewable Energy, Sustainability and the Environment ,Inorganic chemistry ,chemistry.chemical_element ,Onium compound ,General Chemistry ,Electrolyte ,Ion ,chemistry.chemical_compound ,chemistry ,Propylene carbonate ,Energy density ,General Materials Science ,Hexamethylene diisocyanate ,Lithium ,Layer (electronics) - Abstract
Hexamethylene diisocyanate can chemically react with the onium ion produced by the oxidation of propylene carbonate and in situ generate a novel interfacial layer that is stable at high potential. With an appropriate thickness of this film, LiNi1/3Co1/3Mn1/3O2 presents significantly improved rate and cycle performances when tested between 2.5 and 4.6 V (vs. Li/Li+).
- Published
- 2015
25. Cooperative Lewis acid-onium salt catalysis as tool for the desymmetrization of meso-epoxides
- Author
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René Peters, Daniel Brodbeck, Florian Broghammer, and Thorsten Junge
- Subjects
010405 organic chemistry ,Metals and Alloys ,Enantioselective synthesis ,Epoxide ,Onium compound ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Desymmetrization ,Catalysis ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,chemistry ,Bromide ,Materials Chemistry ,Ceramics and Composites ,Organic chemistry ,Lewis acids and bases ,Bifunctional - Abstract
Epoxide desymmetrizations by bromide are very rare despite the large synthetic potential of chiral bromohydrins. Herein we present a new concept for epoxide desymmetrizations in which a bifunctional Lewis acid/ammonium salt catalyst allows for efficient enantioselective epoxide ring openings by Br−. With acetylbromide as a Br− source bromohydrin esters are formed.
- Published
- 2017
26. Interaction of ethidium and tetraphenylphosphonium cations with Salmonella enterica cells
- Author
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Sandra Sakalauskaitė, Valeryia Mikalayeva, and Rimantas Daugelavičius
- Subjects
DNA, Bacterial ,0301 basic medicine ,Tris ,Cell Membrane Permeability ,Tetraphenylphosphonium ,030106 microbiology ,Kinetics ,Biology ,Multidrug resistance ,03 medical and health sciences ,chemistry.chemical_compound ,Onium Compounds ,Organophosphorus Compounds ,Cations ,Drug Resistance, Multiple, Bacterial ,Ethidium ,Fluorometry ,Outer membrane permeability ,lcsh:R5-920 ,Cell Membrane ,Nile red ,Salmonella enterica ,Onium compound ,Fluorescence ,chemistry ,Biochemistry ,Ionic strength ,Efflux inhibitor ,Automotive Engineering ,Biophysics ,Indicators and Reagents ,Efflux ,drug effects ,pharmacology ,Onium compounds ,Organophosphorus compounds ,Drug resistance, multiple, bacterial ,lcsh:Medicine (General) ,Plate reader ,615.33 [udc] - Abstract
Background and objective: One of the main causes of bacterial resistance to antimicrobials is multidrug resistance induced by the increased efficiency of the efflux pumps. In this study we analyzed how the conditions of assay affect the efflux of indicator substrates ethidium (Et+) and tetraphenylphosphonium (TPP+) in Salmonella enterica ser. Typhimurium cells. Impact of the outer membrane permeability barrier, composition and temperature of the medium on accumulation of the indicator compounds also was analyzed. Materials and methods: The fluorescence of Et+ and Nile Red was measured using 96-well plates and a plate reader. In parallel to traditional studies of fluorescence we applied a constructed selective electrode to follow the accumulation of Et+ in S. enterica cells. Simultaneously with monitoring of Et+ concentration in the cell incubation medium, electrochemical measurements of TPP+ accumulation were performed. Furthermore, Et+ and TPP+ were used within the same sample as agents competing for the interaction with the efflux pumps. An inhibitor phenylalanyl-arginyl-β-naphtylamide (PAβN) was applied to evaluate the input of RND-family pumps in the total efflux of these indicator compounds. Results: S. enterica cells with the intact outer membrane (OM) bound very low amounts of Et+ or TPP+. Cells with the permeabilized OM accumulate considerably higher amounts of the indicator compounds at pH 8.0, but only Et+ was considerably accumulated at pH 6.5. At conditions of electrochemical monitoring accumulation of Et+ by the permeabilized cells at 37 °C was considerably faster than at 23 °C, but at the higher temperature most of the cell-accumulated Et+ was extruded back to the medium. The fluorescence of Et+ in suspension of cells incubated in 400 mmol/L Tris buffer was about twice higher compared to 100 mmol/L one. The inhibitory action of TPP+ on Et+ efflux was evident only in 400 mmol/L Tris although PAβN effectively increased Et+ fluorescence at both buffer concentrations. Conclusions: Results of our experiments indicate that ionic strength of the incubation medium influence the selectivity, the medium temperature and the assay conditions impact the kinetics of efflux. The lower accumulated amount and the weaker fluorescence of Et+ registered in slightly acidic medium indicate that ΔΨ plays a role in the accumulation of this indicator cation. The bound amount of Et+ to the de-energized or permeabilized cells considerably varies depending on the conditions and methods of de-energization or permeabilization of cells. Tris/EDTA permeabilization of the cells does not inhibit the efflux.
- Published
- 2017
27. The 2,4-dimethyl-7-pentafluorosulfanyl-5-(trifluoromethyl)dibenzo[b,d]thiophenium trifluoromethanesulfonate: The SF5-analog of Umemoto salt
- Author
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A. Srinivas Reddy, Kenneth K. Laali, and Takao Okazaki
- Subjects
chemistry.chemical_classification ,Trifluoromethyl ,Organic Chemistry ,Salt (chemistry) ,Onium compound ,Survey research ,Biochemistry ,Medicinal chemistry ,Inorganic Chemistry ,Benzenediazonium tetrafluoroborate ,chemistry.chemical_compound ,chemistry ,Suzuki reaction ,Environmental Chemistry ,Organic chemistry ,Physical and Theoretical Chemistry ,Trifluoromethanesulfonate - Abstract
The SF5-analog of the Umemoto salt was synthesized in just two steps by combining our recently reported SF5-biaryl synthesis, via Suzuki coupling with 4-(pentafluorosulfanyl)benzenediazonium tetrafluoroborate, with Magnier's one-pot synthesis of dibenzothiophenium salts employing CF3SO2Na and triflic anhydride. The trifluoromethylating power of this novel onium salt toward reactive arenes was tested in a survey study on small scale.
- Published
- 2014
28. Asymmetric phase-transfer reactions under base-free neutral conditions
- Author
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Keiji Maruoka and Seiji Shirakawa
- Subjects
Catalytic cycle ,Aldol reaction ,Chemistry ,Organocatalysis ,Organic Chemistry ,Drug Discovery ,Enantioselective synthesis ,Onium compound ,Onium ,Biochemistry ,Combinatorial chemistry ,Catalysis ,Bifunctional catalyst - Abstract
Although quaternary onium salt-catalyzed phase-transfer reactions are generally believed to require base additives, we discovered even without any base additives conjugate additions of 3-substituted oxindoles proceeded smoothly in the presence of lipophilic quaternary onium bromide under water-organic biphasic conditions. The mechanism of this novel base-free neutral phase-transfer reaction system was investigated, and the assumed catalytic cycle was presented together with interesting effects of water and lipophilicity of the phase-transfer catalyst. The base-free neutral phase-transfer reaction system could be applied to highly enantioselective conjugate additions, aldol reaction, sulfenylation, and chlorination under the influence of chiral bifunctional onium bromides as key catalysts.
- Published
- 2014
29. Copper-Catalyzed [18F]Fluorination of (Mesityl)(aryl)iodonium Salts
- Author
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Peter J. H. Scott, Melissa E. Rodnick, Joseph J. Topczewski, Allen F. Brooks, Naoko Ichiishi, and Melanie S. Sanford
- Subjects
Fluorine Radioisotopes ,Letter ,Hydrocarbons, Fluorinated ,Molecular Structure ,Chemistry ,Extramural ,Aryl ,Organic Chemistry ,chemistry.chemical_element ,Regioselectivity ,Onium compound ,Biochemistry ,Medicinal chemistry ,Copper ,Catalysis ,chemistry.chemical_compound ,Onium Compounds ,Copper catalyzed ,Combinatorial Chemistry Techniques ,Organic chemistry ,Molecule ,Salts ,Physical and Theoretical Chemistry - Abstract
A practical, rapid, and highly regioselective Cu-catalyzed radiofluorination of (mesityl)(aryl)iodonium salts is described. This protocol utilizes [(18)F]KF to access (18)F-labeled electron-rich, -neutral, and -deficient aryl fluorides under a single set of mild conditions. This methodology is applied to the synthesis of protected versions of two important radiotracers: 4-[(18)F]fluorophenylalanine and 6-[(18)F]fluoroDOPA.
- Published
- 2014
30. Immobilized chiral Mn (III) salen-containing onium salt onto ZnPS-PVPA for asymmetric epoxidation of unfunctionalized olefins
- Author
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Chang Ming Li, Jing Huang, Jiali Cai, and Xiangkai Fu
- Subjects
Inorganic Chemistry ,Homogeneous ,Chemistry ,Polymer chemistry ,Materials Chemistry ,Organic chemistry ,Onium compound ,Physical and Theoretical Chemistry ,Catalysis - Abstract
A series of chiral Mn (III) salen are anchored on ZnPS-PVPA modified by onium salt and characterized. In the asymmetric epoxidation of unfunctionalized olefins with m-CPBA and NaIO4 as oxidants, the supported catalysts demonstrate higher catalytic activities than those of the corresponding homogeneous chiral Mn (III) salen catalyst under the same conditions both for experimental scale and for large-scale reactions. Moreover, the catalysts are stable could be recycled nine times without significant loss of activity, which are provided with the potentiality for application in industry.
- Published
- 2014
31. Visible Light Curable Restorative Composites for Dental Applications Based on Epoxy Monomer
- Author
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Roberta Maria Bongiovanni, Marco Sangermano, Norbert Moszner, Alessandra Vitale, and Peter Burtscher
- Subjects
Materials science ,epoxy monomer ,Radical ,Kinetics ,lcsh:Technology ,Article ,chemistry.chemical_compound ,Polymer chemistry ,General Materials Science ,Irradiation ,Composite material ,lcsh:Microscopy ,lcsh:QC120-168.85 ,lcsh:QH201-278.5 ,lcsh:T ,Cationic polymerization ,Onium compound ,Epoxy ,cationic photopolymerization ,visible light curing ,Monomer ,chemistry ,lcsh:TA1-2040 ,visual_art ,visual_art.visual_art_medium ,lcsh:Descriptive and experimental mechanics ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,lcsh:Engineering (General). Civil engineering (General) ,lcsh:TK1-9971 ,Visible spectrum - Abstract
A cationic photo-curable cycloaliphatic epoxy resin has been investigated as reactive monomer in blue light crosslinking process. We have demonstrated that camphorquinone is able to abstract labile hydrogen from the epoxy monomer, giving rise to the formation of carbon-centered radicals that are oxidized by the onium salt; a complete epoxy group conversion was reached after 50 s of irradiation. The presence of water up to 1 wt% was tolerated without any important detrimental effect on the kinetics of light-curing. The presence of the inorganic filler up to 65 wt% did not significantly influence the curing process.
- Published
- 2014
32. Phenol-functionalized polymerization control additives for negative tone epoxide crosslinking molecular resists
- Author
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Hannah Narcross, Peter J. Ludovice, Laren M. Tolbert, Brandon L. Sharp, and Clifford L. Henderson
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Materials science ,Sulfonium ,Process Chemistry and Technology ,Epoxide ,Onium compound ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,chemistry ,Nucleophile ,Resist ,Polymerization ,Polymer chemistry ,Materials Chemistry ,Phenol ,Electrical and Electronic Engineering ,Instrumentation ,Trifluoromethanesulfonate - Abstract
Controlling undesired polymerization in nominally unexposed regions is critical to achieving high-resolution, defect-free patterns when using negative tone molecular resists based on the crosslinking of epoxides. Two onium salt additives, a photodecomposable nucleophile (PDN) and a photoacid generator (PAG), were functionalized with phenols in order to investigate their use as generalized additives capable of slowing crosslinking and improving the resolution of a variety of epoxide resists. Presented here is a phenol-functionalized PDN [tris(4-hydroxyphenyl)sulfonium triflate (TPS-OH-Tf)] and a phenol-functionalized PAG [tris(4-hydroxyphenyl)sulfonium antimonate (TPS-OH-SbF6)] used in combination with a model epoxide resist (4-Ep). Utilizing additives that contained phenols resulted in a decrease in resist sensitivity, but enabled higher additive loadings which could be used to offset this loss in sensitivity. Using TPS-OH-SbF6 did not provide enough polymerization control to prevent line broadening, and the use of TPS-OH-Tf was still required to achieve sub 35 nm 1:1 line:space patterns. Adding TPS-OH-Tf was also found to improve pattern collapse behavior at reduced (
- Published
- 2018
33. The Effect of Hydrophilic Photoacid Generator on Acid Diffusion in Chemical Amplification Resists
- Author
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Ha Na Kang, Jin Hyuck Jung, Hyun Sang Joo, Haiwon Lee, and Dong Chul Seo
- Subjects
chemistry.chemical_classification ,Glycidyl methacrylate ,Materials science ,Diffusion ,Biomedical Engineering ,Bioengineering ,Onium compound ,General Chemistry ,Polymer ,Photoresist ,Condensed Matter Physics ,Photochemistry ,Thermogravimetry ,chemistry.chemical_compound ,nervous system ,chemistry ,Resist ,General Materials Science ,Methyl methacrylate ,Acids ,Hydrophobic and Hydrophilic Interactions - Abstract
A photoacid generator (PAG) is a component of chemical amplification photoresists (CAR). The most widely used PAG in CAR system is triphenyl onium salt which is well known to one of the best leaving groups from various radiation. Acid diffusion influences resist characteristics in area such as resolution and linewidth control. The structure of the hydrophilic PAG was designed to restrict acid diffusion within the photoresist. Acid amplification was suppressed by the hydroxyl group-acid interaction. Novel PAGs with functional groups were synthesized and characterized. Poly(GMA-co-MMA) was synthesized with a combination of crosslinkable glycidyl methacrylate (GMA) and highly refractive methyl methacrylate (MMA). The synthesized polymers were confirmed by NMR and FT-IR, and their thermal properties were studied using TGA and DSC. The resists were evaluated as a positive type resist for ArF lithography. PAGs exhibited good acid generation efficiency with controlled acid diffusion. We found that the energy latitude property of the photoresist was improved with hydroxyl-PAG.
- Published
- 2014
34. Efficient Ring Opening Reaction of Epoxides with Oxygen Nucleophiles Catalyzed by Quaternary Onium Salt
- Author
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Dae Won Cho, Gyoosoon Park, Choon Sup Ra, Jin Won Kim, and Sung Hong Kim
- Subjects
chemistry.chemical_classification ,chemistry.chemical_compound ,chemistry ,Nucleophile ,Epoxide ,Phosphonium salt ,Organic chemistry ,Phenol ,Salt (chemistry) ,Onium compound ,General Chemistry ,Ring (chemistry) ,Catalysis - Abstract
Ring opening reactions of epoxides with oxygen nucleophiles catalyzed by a variety of quaternary onium salt, such as ammonium or phosphonium salt were explored. The results showed that tetrabutylphosphonium bromide (TBPB) among salts serves as the most efficient catalyst for this process and that expoxide ring opening reactions with a variety of oxygen nucleophiles including carboxyic acid and phenol, promoted using this salt, lead to generate readily purifiable products in excellent yields.
- Published
- 2013
35. Relative basicities of cyclic ethers and esters. Chemistry of importance to ring-opening co- and terpolymerization reactions
- Author
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Wan-Chun Chung and Donald J. Darensbourg
- Subjects
Epoxide ,Onium compound ,Ring (chemistry) ,Photochemistry ,Medicinal chemistry ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,Monomer ,chemistry ,Materials Chemistry ,Copolymer ,Reactivity (chemistry) ,Physical and Theoretical Chemistry ,Benzene - Abstract
We have re-evaluated the use of the red-shifted ν OD vibrational mode in CH 3 OD as a result of hydrogen-bonding to various oxygen donor ligands in determining the basicity strengths of such donors. This was accomplished by initially defining the relationship of the analogous vibrational shifts of several amines with respect to the corresponding shift in benzene versus their well-established p K b s in water. The reactivity ratios for terpolymerization processes involving two different epoxides and CO 2 catalyzed by binary (salen)MX/onium salt (M = Cr or Co) catalyst systems were determined by a Fineman–Ross analysis, i.e., quantifying the amount of respective monomers in the polymer versus that in the feed during the early stages of the process. These reactivity ratios reflect the tendencies for an epoxide monomer to self-propagate or cross-propagate during the monomer enchainment process. The relative basicities of cyclic ethers were shown to greatly influence the interpretation of these measured reactivity ratios.
- Published
- 2013
36. Synthesis and Reactivity of Aryl(alkynyl)iodonium Salts
- Author
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George J. Ellames, Michael A. Carroll, Luke I. Dixon, Ross W. Harrington, William Clegg, and Thomas J. Gregson
- Subjects
chemistry.chemical_compound ,chemistry ,Aryl ,Reagent ,Organic Chemistry ,Halogen ,Organic chemistry ,Reactivity (chemistry) ,Onium compound ,Physical and Theoretical Chemistry ,Medicinal chemistry ,Cycloaddition - Abstract
The first practical, yet simple, preparation of aryl(alkynyl)iodonium trifluoroacetate salts is described. The generic nature of this synthetic method has allowed the production of a range of aryl(alkynyl)iodonium trifluoroacetate salts with independent variation of both the alkynyl and aryliodo groups in yields of 30–85 %. Application of these new reagents to the synthesis of a series of 2-arylfuro[3,2-c]pyridines (40–64 %) highlights the potential of this class of materials as precursors to bioactive heterocyclic structures. These experiments have also demonstrated that, in this case, the effect of the aryliodo group on the reaction is negligible.
- Published
- 2013
37. Redox Intitiated Cationic Polymerization
- Author
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James V. Crivello
- Subjects
Polymers and Plastics ,Reducing agent ,Chemistry ,Organic Chemistry ,technology, industry, and agriculture ,Cationic polymerization ,Onium compound ,engineering.material ,Onium ,Condensed Matter Physics ,Photochemistry ,Redox ,Silane ,chemistry.chemical_compound ,Monomer ,Polymer chemistry ,Materials Chemistry ,engineering ,Noble metal - Abstract
Two novel redox initiator systems have been developed for carrying out the cationic polymerizations of vinyl and heterocyclic monomers. The initiators are based on various onium salts as the oxidant together with an alkylborane or an organosilane as the reducing agent. Using both redox cationic initiator systems, the polymerizations of a wide variety of monomers can be carried out at or below room temperature in the presence or absence of unreactive solvents. Also described in this communication is the novel use of a two-component redox system in which the reducing agent, a silane, is delivered to the monomer sample in the vapor state. Optical pyrometry (infrared thermography) was employed as a convenient method with which to monitor the polymerizations in real-time. A study of the effects of variations in the structures of the onium salt, the silane and the type of noble metal catalyst were carried out. The use of these initiator systems for carrying out commercially attractive crosslinking polymerizations for coatings, composites and electronic encapsulations is discussed.
- Published
- 2013
38. Aims and Possibilities of Applied Plant Bioregulation
- Author
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Jung, J. and Bopp, Martin, editor
- Published
- 1986
- Full Text
- View/download PDF
39. ChemInform Abstract: Ionic Liquids as Novel Media for Electrophilic/Onium Ion Chemistry and Metal-mediated Reactions: a Progress Summary
- Author
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Kenneth K. Laali
- Subjects
Metal ,chemistry.chemical_compound ,Chemistry ,visual_art ,Ionic liquid ,Polymer chemistry ,Electrophile ,visual_art.visual_art_medium ,Onium compound ,General Medicine ,Catalysis - Abstract
The account presented here summarizes progress from the author's laboratory during the past 15 years on the application of room temperature ionic liquids (RTILs) as solvents and catalysts in electrophilic/onium ion chemistry as well as in metal-mediated bond forming reactions.
- Published
- 2016
40. A long-linker conjugate of fluorescein and triphenylphosphonium as mitochondria-targeted uncoupler and fluorescent neuro- and nephroprotector
- Author
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S. S. Jankauskas, Khailova Ls, Dmitry B. Zorov, Egor Y. Plotnikov, Yuri N. Antonenko, Denis N. Silachev, T. I. Danilina, Galina A. Korshunova, Tatyana I. Rokitskaya, Stepan S. Denisov, and Elena A. Kotova
- Subjects
0301 basic medicine ,Protonophore ,Uncoupling Agents ,Biophysics ,Oxidative phosphorylation ,Mitochondrion ,Biochemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Onium Compounds ,Organophosphorus Compounds ,Animals ,Fluorescein ,Molecular Biology ,Membrane potential ,Liposome ,030102 biochemistry & molecular biology ,Chemistry ,Onium compound ,Mitochondria ,Rats ,030104 developmental biology ,Neuroprotective Agents - Abstract
Background Limited uncoupling of oxidative phosphorylation is known to be beneficial in various laboratory models of diseases. Linking a triphenyl-phosphonium cation to fluorescein through a decyl (C 10 ) spacer yields a fluorescent uncoupler, coined mitoFluo, that selectively accumulates in energized mitochondria (Denisov et al., Chem.Commun. 2014). Methods Proton-transport activity of mitoFluo was tested in liposomes reconstituted with bacteriorhodopsin. To examine the uncoupling action on mitochondria, we monitored mitochondrial membrane potential in parallel with oxygen consumption. Neuro- and nephroprotecting activity was detected by a limb-placing test and a kidney ischemia/reperfusion protocol, respectively. Results We compared mitoFluo properties with those of its newly synthesized analog having a short (butyl) spacer (C 4 -mitoFluo). MitoFluo, but not C 4 -mitoFluo, caused collapse of mitochondrial membrane potential resulting in stimulation of mitochondrial respiration. The dramatic difference in the uncoupling activity of mitoFluo and C 4 -mitoFluo was in line with the difference in their protonophoric activity on a lipid membrane. The accumulation of mitoFluo in mitochondria was more pronounced than that of C 4 -mitoFluo . MitoFluo decreased the rate of ROS production in mitochondria. MitoFluo was effective in preventing consequences of brain trauma in rats: it suppressed trauma-induced brain swelling and reduced a neurological deficit. Besides, mitoFluo attenuated acute kidney injury after ischemia/reperfusion in rats. Conclusions A long alkyl linker was proved mandatory for mitoFluo to be a mitochondria- targeted uncoupler. MitoFluo showed high protective efficacy in certain models of oxidative stress-related diseases. General significance MitoFluo is a candidate for developing therapeutic and fluorescence imaging agents to treat brain and kidney pathologies.
- Published
- 2016
41. Pd@[nBu4][Br] as a simple catalytic system for N-alkylation reactions with alcohols
- Author
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Oana Pascu, Bastien Cacciuttolo, Mathieu Pucheault, Cyril Aymonier, Institut des Sciences Moléculaires (ISM), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Université Sciences et Technologies - Bordeaux 1-Université Montesquieu - Bordeaux 4-Institut de Chimie du CNRS (INC), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB)
- Subjects
education ,Pharmaceutical Science ,Nanoparticle ,Alkylation ,010402 general chemistry ,7. Clean energy ,01 natural sciences ,Analytical Chemistry ,Catalysis ,lcsh:QD241-441 ,lcsh:Organic chemistry ,Drug Discovery ,Organic chemistry ,Physical and Theoretical Chemistry ,Supercritical carbon dioxide ,010405 organic chemistry ,Chemistry ,nanoparticle ,Organic Chemistry ,Condensation ,Palladium nanoparticles ,onium salt N-alkylation ,Onium compound ,[CHIM.MATE]Chemical Sciences/Material chemistry ,Onium ,N-alkylation ,0104 chemical sciences ,Chemistry (miscellaneous) ,onium salt ,Molecular Medicine - Abstract
International audience; Palladium nanoparticles, simply and briefly generated in commercial and cheap onium salts using supercritical carbon dioxide, have been found to be an effective catalytic system for additive free N-alkylation reaction using alcohols via cascade oxidation/condensation/reduction steps.
- Published
- 2016
42. Diazobenzo[a]fluorene derivatives as visible photosensitizers for cationic polymerization
- Author
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Radosław Podsiadły, Jolanta Sokołowska, Ewa Chrześcijańska, Agnieszka Marzena Szymczak, and Karolina Podemska
- Subjects
Process Chemistry and Technology ,General Chemical Engineering ,Cationic polymerization ,Onium compound ,Fluorene ,Onium ,Photochemistry ,Gibbs free energy ,Electron transfer ,chemistry.chemical_compound ,symbols.namesake ,chemistry ,symbols ,Cyclohexene oxide ,Visible spectrum - Abstract
Photoredox pairs consisting of dyes based on diazobenzo[a]fluorene derivatives and commercially available onium salts (diaryliodonium and triphenylsulfonium salts) are tested as effective initiator systems for the cationic polymerization of cyclohexene oxide using visible light. The efficiency of these initiator systems is discussed based on the free energy change for the electron transfer from examined dyes to the onium compounds. The most efficient sensitizers are the dyes with the lowest oxidation potential and the highest −ΔGel. A linear relationship between the quantum yields of acid release Φ(H+) and the conversion of CHO is observed.
- Published
- 2012
43. Efficient Method for Varying the Anions in Quaternary Onium Halides
- Author
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Jong Yeob Jeon, Jobi Kodiyan Varghese, Bun Yeoul Lee, Ji Hae Park, and Suck-Hyun Lee
- Subjects
Green chemistry ,Ion exchange ,Chemistry ,ved/biology ,Organic Chemistry ,ved/biology.organism_classification_rank.species ,Inorganic chemistry ,Halide ,Onium compound ,Onium ,Trimethyl phosphate ,chemistry.chemical_compound ,Ionic liquid ,Physical and Theoretical Chemistry ,Conjugate acid - Abstract
Quaternary onium salts of halides can be efficiently converted into the corresponding quaternary onium salts of various anions [NO3–, BF4–, PF6–, CF3SO3–, CH3SO3–, ClO4–, p-CH3C6H4SO3–, CF3CO2–, 2,4-(NO2)2C6H3O–] by treating the onium halide with trimethyl phosphate under neat condition in the presence of an equivalent amount of conjugate acid of the desired anion.
- Published
- 2012
44. Estimation of the catalytic activity of onium chlorides and bromides in the alkaline hydrolysis of amino acids esters
- Author
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A. N. Shendrik, V. S. Doroshkevich, and O. V. Baranova
- Subjects
chemistry.chemical_compound ,chemistry ,Organic Chemistry ,Polymer chemistry ,Enthalpy ,Inorganic chemistry ,Hydroxide ,Onium compound ,Phosphonium ,Pyridinium ,Onium ,Alkaline hydrolysis ,Catalysis - Abstract
Relations were investigated between the structure of a series of onium salts, rates of alkaline hydrolysis catalyzed by the salts of 4-nitrophenyl N-benzyloxycarbonylglycinate in a two-phase liquid-liquid system, and the value of the standard exchange enthalpy of anions in ion pairs with the catalyst cation calculated by the semiempiric PM3 method. The catalytic activity of ammonium, phosphonium, pyridinium, imidazolium, and benzimidazolium salts in a wide range of cation structures varies in parallel with the enthalpy of formation of the active form of the catalyst by the exchange of the anion with a hydroxide ion.
- Published
- 2012
45. 4-N,N-Dimethylaminopyridine Promoted Selective Oxidation of Methyl Aromatics with Molecular Oxygen
- Author
-
Jie Xu, Zhan Zhang, Jin Gao, and Feng Wang
- Subjects
Reaction mechanism ,Pyridines ,Pharmaceutical Science ,Medicinal chemistry ,Catalysis ,Analytical Chemistry ,lcsh:QD241-441 ,chemistry.chemical_compound ,lcsh:Organic chemistry ,Bromide ,Benzyl Compounds ,Drug Discovery ,Pyridine ,Organic chemistry ,organocatalysis ,4-Aminopyridine ,Physical and Theoretical Chemistry ,Nuclear Magnetic Resonance, Biomolecular ,molecular oxygen ,Communication ,Organic Chemistry ,Temperature ,Onium compound ,selective oxidation ,methyl aromatics ,Oxygen ,4-N,N-dimethylaminopyridine ,chemistry ,Benzyl bromide ,Chemistry (miscellaneous) ,Organocatalysis ,Solvents ,Molecular Medicine ,molecularoxygen ,Oxidation-Reduction ,selectiveoxidation ,methylaromatics - Abstract
4-N,N-Dimethylaminopyridine (DMAP) as catalyst in combination with benzyl bromide was developed for the selective oxidation of methyl aromatics. DMAP exhibited higher catalytic activity than other pyridine analogues, such as 4-carboxypyridine, 4-cyanopyridine and pyridine. The sp3 hybrid carbon-hydrogen (C-H) bonds of different methyl aromatics were successfully oxygenated with molecular oxygen. The real catalyst is due to the formation of a pyridine onium salt from the bromide and DMAP. The onium salt was well characterized by NMR and the reaction mechanism was discussed.
- Published
- 2012
46. Two- and Three-Component Visible Light Photoinitiating Systems for Radical Polymerization Based on Onium Salts: An Overview of Mechanistic and Laser Flash Photolysis Studies
- Author
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Hernán A. Montejano, Carlos M. Previtali, and María Lorena Gomez
- Subjects
chemistry.chemical_classification ,Renewable Energy, Sustainability and the Environment ,lcsh:TJ807-830 ,Radical polymerization ,lcsh:Renewable energy sources ,Salt (chemistry) ,Onium compound ,General Chemistry ,Onium ,Photochemistry ,Atomic and Molecular Physics, and Optics ,Photopolymer ,Polymerization ,chemistry ,Polymer chemistry ,Flash photolysis ,General Materials Science ,Photoinitiator - Abstract
A review of our work on two- and-three component photoinitiator systems is presented. The emphasis is in on visible light polymerization in aqueous media. The systems discussed comprise a synthetic dye as sensitizer and an onium salt as coinitiator, or a dye-amine-onium salt with the amine as coinitiator and the onium salt as an enhancer of the polymerization efficiency. The effect of the composition of the system on the photopolymerization kinetics was analyzed. To this end, the photophysics and photochemistry of the dye under polymerization conditions was explored by means of stationary and time-resolved spectroscopic methods. Different dyes and onium salts were investigated. The action mechanism of the different photoinitiators systems is discussed.
- Published
- 2012
47. Formation and Stability of the 4-Methoxyphenonium Ion in Aqueous Solution
- Author
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Daisuke Hara, Yutaka Tsuji, John P. Richard, and Rui Hagimoto
- Subjects
Ions ,Aqueous solution ,Molecular Structure ,Chemistry ,Organic Chemistry ,Water ,Benzyl Compounds ,Stereoisomerism ,Onium compound ,Article ,Ion ,Solutions ,Onium Compounds ,Computational chemistry ,Organic chemistry ,Molecule - Abstract
The reaction of 2-methoxyphenylethyl tosylate (MeO-1-Ts) is first-order in [N(3)(-)]. A carbon-13 NMR analysis of the products of the reactions of MeO-1-[α-(13)C]Ts shows the formation of MeO-1-[β-(13)C]OH and MeO-1-[β-(13)C]N(3) from the trapping of a symmetrical 4-methoxyphenonium ion reaction intermediate 2(+). An analysis of the rate and product data provides a value of k(az)/k(s) = 83 M(-1) for partitioning of 2(+) between addition of azide ion and solvent. These data set a limit for the lifetime of 2(+) in aqueous solution.
- Published
- 2011
48. 4,4′,4″-Tris(acetoxymethylene)triphenylamine: An Efficient Photoacid Promoted Chemical Cross-Linker for Polyvinylcarbozole and Its Applications for Photolithographic Hole-Transport Materials
- Author
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Yu-Xun Wang and Man-kit Leung
- Subjects
Tris ,Materials science ,Polymers and Plastics ,Carbazole ,Organic Chemistry ,Onium compound ,Photochemistry ,Triphenylamine ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,Photoacid ,Irradiation ,Photomask ,Cross linker - Abstract
A photolithographic hole transport material of 4,4′,4″-tris(acetoxymethylene)triphenylamine (1), polyvinylcarbazole (PVK), and diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (DIAS, a photoacid generator) has been successfully formulated. After exposure to UV irradiation (λ > 200 nm) through a patterned UV (λ >200 nm) photomask for 6 min, followed by a standard postbaking treatment at 130 °C for 5 min under vacuum and development in CH2Cl2, a negative tone image was established through the photoinduced chemical cross-linking reactions. This approach can be implemented to PLED applications. Under the optimized conditions, the polymeric light-emitting device (PLED) of ITO/photolithographic HTL/PVK–Ir(PPy)3–PBD/Mg–Ag, with a turn-on voltage of 13.0 V (100 cd/m2), a maximum brightness of 8220 cd/m2, and a current efficiency of 9.0 cd/A was achieved. Our study reviewed that three parallel mechanisms, including the photodimerization of the carbazole units, the Crivello onium salt sensitization mechanism, ...
- Published
- 2011
49. Chemical structure and catalytic activity of quaternary onium salt-type triphase catalysts based on CPS microspheres
- Author
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Zhangbin Wang, Baojiao Gao, and Lin Wang
- Subjects
Polymers and Plastics ,Chemistry ,Chemical structure ,Onium compound ,General Chemistry ,Onium ,Surfaces, Coatings and Films ,Catalysis ,Matrix (chemical analysis) ,chemistry.chemical_compound ,Benzyl chloride ,Materials Chemistry ,Organic chemistry ,Polystyrene ,Sodium acetate - Abstract
In this work, diversified quaternary onium salt-type triphase catalysts (TPC) were prepared based on crosslinked polystyrene (CPS) microspheres, and the relationship between their chemical structures and catalytic activities in liquid-solid-liquid reaction system were investigated in depth by using the esterification reaction of benzyl chloride with sodium acetate as a model system. The experimental results indicate that the chemical structures of the TPC affect their catalytic activity greatly and there are four basic points: (1) the quaternary phosphonium-type TPC have higher activity than quaternary ammonium-type catalyst; (2) the TPC with more lipophilic substitutes at N atom have higher catalytic activity; (3) the TPC with longer spacer arm, which links quaternary onium salt group to the matrix microsphere, have higher catalytic activity; (4) the bonding density of quaternary onium salt group on the polymeric carrier affects the hydrophilic and hydrophobic property of the TPC, and consequently, influences the catalytic activity significantly. For a given triphase catalysis system, there is an optimal bonding density of quaternary onium salt group on the solid catalysts. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
- Published
- 2011
50. A novel approach for synthesis of 3-amino-5-aryl-2,5-dihydropyridazines using onium salt as soluble support
- Author
-
Zu Xing Chen, G. C. Yang, Meng Gao, and C. F. Lu
- Subjects
chemistry.chemical_compound ,Solid-phase synthesis ,chemistry ,Aryl ,Organic chemistry ,Onium compound ,General Chemistry ,Solution phase - Abstract
In this work it was presented an application of task specific onium salt as soluble support for the synthesis of 3-amino-5-aryl-2,5-dihydropyridazines. This soluble support is of wide applicability and combines advantages of solid phase synthesis without its limitations with those of solution phase chemistry. After a simple washing step, products were cleaved from the supports and obtained in good yields.
- Published
- 2011
Catalog
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