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Journal articles on the topic 'Zwitterionic catalyst'

Author: Grafiati

Published: 4 June 2021

Last updated: 10 February 2022

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1

Trendafilova, Ivalina, Andraž Šuligoj, Alenka Ristić, et al. "Evolution of Surface Catalytic Sites on Bimetal Silica-Based Fenton-Like Catalysts for Degradation of Dyes with Different Molecular Charges." Nanomaterials 10, no. 12 (2020): 2419. http://dx.doi.org/10.3390/nano10122419.

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We present here important new findings on the direct synthesis of bimetal Cu-Mn containing porous silica catalyst and the effects of structure-directing agent removal from the prepared nanomaterial on the evolution of surface catalytic sites. The extraction-calcination procedure of the structure-directing agent removal led to the formation of Cu and Mn oxo-clusters and Cu and Mn oxide nanoparticles smaller than 5 nm, while the solely calcination procedure led to the mentioned species and in addition to the appearance of CuO nanoparticles 20 nm in size. Catalysts were tested in the Fenton-like catalytic degradation of dyes with different molecular charge (cationic, anionic, and zwitterionic) as model organic pollutants in wastewater at neutral pH. Significantly faster degradation of cationic and anionic dyes in the first 60 min was observed with the catalyst containing larger CuO nanoparticles (>20 nm) due to the less hindered generation of •OH radicals and slower obstructing of the active sites on the catalysts surface by intermediates. However, this was not found beneficial for zwitterionic dye with no adsorption on the catalysts surface, where the catalyst with smaller Cu species performed better.

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2

Qiu, Pei, Jing Yang Zhao, Xu Shi, and Xin Hong Duan. "An efficient water-soluble surfactant-type palladium catalyst for Suzuki cross-coupling reactions in pure water at room temperature." New Journal of Chemistry 40, no. 8 (2016): 6568–72. http://dx.doi.org/10.1039/c6nj00377j.

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3

Jin, Gong, Jing Sun, and Chao-Guo Yan. "Formation of zwitterionic salts via three-component reaction of benzimidazolium bromides, aromatic aldehydes and 1,3-indanedione." RSC Advances 6, no. 87 (2016): 84379–87. http://dx.doi.org/10.1039/c6ra16838h.

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4

Jia, Xiaofei, Mengru Zhang, Fan Pan, et al. "Zwitterionic Nickel(II) Catalyst for CO–Ethylene Alternating Copolymerization." Organometallics 34, no. 20 (2015): 4798–801. http://dx.doi.org/10.1021/acs.organomet.5b00676.

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5

Monfredini, Anna, Veronica Santacroce, Pierre-Alexandre Deyris, et al. "Boosting catalyst activity in cis-selective semi-reduction of internal alkynes by tailoring the assembly of all-metal aromatic tri-palladium complexes." Dalton Transactions 45, no. 40 (2016): 15786–90. http://dx.doi.org/10.1039/c6dt01840h.

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6

Uraguchi, Daisuke, Kohsuke Kato, and Takashi Ooi. "o-Quinone methide with overcrowded olefin component as a dehydridation catalyst under aerobic photoirradiation conditions." Chemical Science 12, no. 8 (2021): 2778–83. http://dx.doi.org/10.1039/d0sc06240e.

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An o-quinone methide (o-QM) featuring an overcrowded olefinic framework is introduced, which exhibits dehydridation activity owing to its enhanced zwitterionic character, particularly through photoexcitation.

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7

Cipot, Judy, Robert McDonald, and Mark Stradiotto. "New bidentate cationic and zwitterionic relatives of Crabtree's hydrogenation catalyst." Chemical Communications, no. 39 (2005): 4932. http://dx.doi.org/10.1039/b510253g.

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8

Naumann, Stefan, Johannes Klein, Dongren Wang, and Michael R. Buchmeiser. "Convenient preparation of high molecular weight poly(dimethylsiloxane) using thermally latent NHC-catalysis: a structure-activity correlation." Beilstein Journal of Organic Chemistry 11 (November 20, 2015): 2261–66. http://dx.doi.org/10.3762/bjoc.11.246.

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The polymerization of octamethylcyclotetrasiloxane (D4) is investigated using several five-, six- and seven-membered N-heterocyclic carbenes (NHCs). The catalysts are delivered in situ from thermally susceptible CO2 adducts. It is demonstrated that the polymerization can be triggered from a latent state by mild heating, using the highly nucleophilic 1,3,4,5-tetramethylimidazol-2-ylidene as organocatalyst. This way, high molecular weight PDMS is prepared (up to >400 000 g/mol, 1.6 < Ð M < 2.5) in yields >95%, using low catalyst loadings (0.2–0.1 mol %). Furthermore, the results suggest that a nucleophilic, zwitterionic mechanism is in operation, in preference to purely anionic polymerization.

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9

Banik, Bimal Krishna, Bubun Banerjee, Gurpreet Kaur, Shivam Saroch, and Rajat Kumar. "Tetrabutylammonium Bromide (TBAB) Catalyzed Synthesis of Bioactive Heterocycles." Molecules 25, no. 24 (2020): 5918. http://dx.doi.org/10.3390/molecules25245918.

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During the last two decades, tetrabutylammonium bromide (TBAB) has gained significant attention as an efficient metal-free homogeneous phase-transfer catalyst. A catalytic amount of TBAB is sufficient to catalyze various alkylation, oxidation, reduction, and esterification processes. It is also employed as an efficient co-catalyst for numerous coupling reactions. It has also acted as an efficient zwitterionic solvent in many organic transformations under molten conditions. In this review, we have summarized the recent developments on TBAB-catalyzed protocols for the efficient synthesis of various biologically promising heterocyclic scaffolds.

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10

Lipilin, Dmitry L., Alexander E. Frumkin, Alexey Y. Tyurin, Vitalij V. Levin, and Alexander D. Dilman. "Photoredox Catalyzed Dealkylative Aromatic Halogen Substitution with Tertiary Amines." Molecules 26, no. 11 (2021): 3323. http://dx.doi.org/10.3390/molecules26113323.

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A reaction of aromatic halides bearing electron-withdrawing groups with tertiary amines in the presence of an iridium catalyst under blue light irradiation is described. Products of the aromatic substitution of the halide by the dialkylamino fragment are obtained. The interaction of aryl radicals with tertiary amines to generate zwitterionic radical species is believed to be the key factor responsible for the reaction efficiency.

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11

Yan, Ru-Jie, Bao-Xin Liu, Yuan Hu, Wei Du, and Ying-Chun Chen. "Generation of zwitterionic trifluoromethyl N-allylic ylides and their use in switchable divergent annulations." Chemical Communications 57, no. 72 (2021): 9056–59. http://dx.doi.org/10.1039/d1cc03830c.

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12

Savić, Nada D., David E. Salazar Marcano, Thomas Quanten, and Tatjana N. Parac-Vogt. "Broadening the Scope of Polyoxometalates as Artificial Proteases in Surfactant Solutions: Hydrolysis of Ovalbumin by Zr(IV)-Substituted Keggin Complex." Inorganics 9, no. 4 (2021): 22. http://dx.doi.org/10.3390/inorganics9040022.

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Development of catalysts for the selective hydrolysis of proteins is challenging, yet important for many applications in biotechnology and proteomics. The hydrolysis of hydrophobic proteins is particularly challenging, as due to their poor solubility, the use of surfactants is often required. In this study, the proteolytic potential of catalyst systems based on the Zr(IV)-substituted Keggin polyoxometalate (Et2NH2)10[Zr(PW11O39)2] (Zr-K 1:2) and three different surfactants (ionic SDS (sodium dodecyl sulfate); zwitterionic Zw3-12 (n-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate); and CHAPS (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate)), which differ in structure and polarity, has been investigated. Hydrolysis of ovalbumin (OVA) was examined in the presence of Zr-K 1:2 and surfactants by sodium dodecyl sulfate poly(acrylamide) gel electrophoresis (SDS-PAGE), which showed the appearance of new polypeptide fragments at lower molecular weight, indicating that selective hydrolysis of OVA took place for all three catalyst systems. The same fragmentation pattern was observed, showing that the selectivity was not affected by surfactants. However, the surfactants influenced the performance of the catalyst. Hence, the interactions of OVA with surfactants and Zr-K 1:2 were investigated using different techniques such as tryptophan fluorescence, Circular Dichroism, and Dynamic Light Scattering. The speciation of the catalyst in surfactant solutions was also followed by 31P Nuclear Magnetic Resonance spectroscopy providing insight into its stability under reaction conditions.

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13

Wasilke, Julia-Christina, Zachary J. A. Komon, Xianhui Bu, and Guillermo C. Bazan. "Ring Closure of 1,4-Pentadiene to Cyclopentene by a Zwitterionic Nickel Catalyst." Organometallics 23, no. 18 (2004): 4174–77. http://dx.doi.org/10.1021/om049600n.

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14

Grigolo, T. A., S. D. de Campos, F. Manarin, et al. "Catalytic properties of a cobalt metal–organic framework with a zwitterionic ligand synthesized in situ." Dalton Transactions 46, no. 45 (2017): 15698–703. http://dx.doi.org/10.1039/c7dt03364h.

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15

Rostamnia, Sadegh. "In situ generation and protonation of the isocyanide/acetylene adduct: a powerful catalyst-free strategy for multicomponent synthesis of ketenimines, aza-dienes, and heterocycles." RSC Advances 5, no. 117 (2015): 97044–65. http://dx.doi.org/10.1039/c5ra20455k.

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In addition to isocyanide-based Ugi, Passerini, van Leusen, and Orru multicomponent reactions, a new class of isocyanide/acetylene-based multicomponent reactions, using zwitterionic adducts, have emerged as powerful methods to synthesize biologically interesting molecules.

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16

Suresh, Lakshmi, Ralte Lalrempuia, Jonas B. Ekeli, et al. "Unsaturated and Benzannulated N-Heterocyclic Carbene Complexes of Titanium and Hafnium: Impact on Catalysts Structure and Performance in Copolymerization of Cyclohexene Oxide with CO2." Molecules 25, no. 19 (2020): 4364. http://dx.doi.org/10.3390/molecules25194364.

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Tridentate, bis-phenolate N-heterocyclic carbenes (NHCs) are among the ligands giving the most selective and active group 4-based catalysts for the copolymerization of cyclohexene oxide (CHO) with CO2. In particular, ligands based on imidazolidin-2-ylidene (saturated NHC) moieties have given catalysts which exclusively form polycarbonate in moderate-to-high yields even under low CO2 pressure and at low copolymerization temperatures. Here, to evaluate the influence of the NHC moiety on the molecular structure of the catalyst and its performance in copolymerization, we extend this chemistry by synthesizing and characterizing titanium complexes bearing tridentate bis-phenolate imidazol-2-ylidene (unsaturated NHC) and benzimidazol-2-ylidene (benzannulated NHC) ligands. The electronic properties of the ligands and the nature of their bonds to titanium are studied using density functional theory (DFT) and natural bond orbital (NBO) analysis. The metal–NHC bond distances and bond strengths are governed by ligand-to-metal σ- and π-donation, whereas back-donation directly from the metal to the NHC ligand seems to be less important. The NHC π-acceptor orbitals are still involved in bonding, as they interact with THF and isopropoxide oxygen lone-pair donor orbitals. The new complexes are, when combined with [PPN]Cl co-catalyst, selective in polycarbonate formation. The highest activity, albeit lower than that of the previously reported Ti catalysts based on saturated NHC, was obtained with the benzannulated NHC-Ti catalyst. Attempts to synthesize unsaturated and benzannulated NHC analogues based on Hf invariably led, as in earlier work with Zr, to a mixture of products that include zwitterionic and homoleptic complexes. However, the benzannulated NHC-Hf complexes were obtained as the major products, allowing for isolation. Although these complexes selectively form polycarbonate, their catalytic performance is inferior to that of analogues based on saturated NHC.

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17

Yavari, Issa, and Aliyeh Khajeh-Khezri. "Recent Advances in the Synthesis of Hetero- and Carbocyclic Compounds and Complexes Based on Acenaphthylene-1,2-dione." Synthesis 50, no. 20 (2018): 3947–73. http://dx.doi.org/10.1055/s-0037-1610209.

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Acenaphthylene-1,2-dione has been utilized in a wide range of reactions as a starting material for the synthesis of hetero- and carbocyclic compounds and complexes. This review provides a short summary of the recent advances in the application of acenaphthylene-1,2-dione in the synthesis of hetero- and carbocyclic systems and bioactive compounds. In addition, the applications of acenaphthylene-1,2-dione in the synthesis of spiro compounds, propellanes, and ligands in catalyst reactions, from 2002 to early 2018, are included.1 Introduction2 Synthesis of Spiro Compounds Employing Acenaphthylene-1,2-dione2.1 Methods for the Construction of Spiro Compounds2.1.1 By 1,3-Dipolar Cycloaddition of Acenaphthylene-1,2-dione via Azomethine Ylides2.1.2 By Multicomponent Reactions of Acenaphthylene-1,2-dione with C–H Acidic Compounds2.1.3 By Reaction of Acenaphthylene-1,2-dione with Zwitterionic Intermediates2.1.4 By Substitution and Multicomponent Reactions of Acenaphth- ylene-1,2-dione with Different Nucleophiles3 Synthesis of Propellanes by Employing Acenaphthylene-1,2-dione3.1 Methods for the Construction of Propellanes Based on Acenaph- thylene-1,2-dione3.1.1 By Reaction of Acenaphthylene-1,2-dione with Nucleophiles3.1.2 By Reaction of Acenaphthylene-1,2-dione with Binucleophiles4 Synthesis of Ligands Employing Acenaphthylene-1,2-dione for Catalyst Reactions5 Synthesis of Novel Hetero- and Carbocyclic Compounds Employing Acenaphthylene-1,2-dione5.1 By Reaction of Acenaphthylene-1,2-dione with Nucleophiles5.2 By Reaction of Acenaphthylene-1,2-dione with Zwitterionic Intermediates5.3 By Ring Opening and Ring Enlargement6 Conclusion

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18

van der Heijden, Harry, Bart Hessen та A. Guy Orpen. "A Zwitterionic Zirconocene Alkyl Complex as a Single-Component α-Olefin Dimerization Catalyst". Journal of the American Chemical Society 120, № 5 (1998): 1112–13. http://dx.doi.org/10.1021/ja971977f.

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19

Alonso, Miguel E., and Raiza Fernández. "Effect of catalyst on zwitterionic intermediacy in additions of dimethyl diazomalonate to vinyl ethers." Tetrahedron 45, no. 11 (1989): 3313–20. http://dx.doi.org/10.1016/s0040-4020(01)81010-3.

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20

Ohmatsu, Kohsuke, Ryuhei Suzuki, Yukino Furukawa, Makoto Sato, and Takashi Ooi. "Zwitterionic 1,2,3-Triazolium Amidate as a Catalyst for Photoinduced Hydrogen-Atom Transfer Radical Alkylation." ACS Catalysis 10, no. 4 (2019): 2627–32. http://dx.doi.org/10.1021/acscatal.9b04491.

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21

Sun, Yimin, Warren E. Piers, Yimin Sun та Steven J. Rettig. "Zwitterionic alkene polymerization catalyst derived from Cp2Zr(η2-C2H4)PPh2Me and B(C6F5)3". Chemical Communications, № 1 (1998): 127–28. http://dx.doi.org/10.1039/a705782b.

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22

Fan, Yifei, Nicola Migliore, Patrizio Raffa, Ranjita K. Bose, and Francesco Picchioni. "Synthesis of Zwitterionic Copolymers via Copper-mediated Aqueous Living Radical Grafting Polymerization on Starch." Polymers 11, no. 2 (2019): 192. http://dx.doi.org/10.3390/polym11020192.

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[2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA) is a well-studied sulfobetaine-methacrylate as its zwitterionic structure allows the synthesis of polymers with attractive properties like antifouling and anti-polyelectrolyte behavior. In the present work, we report the Cu0-mediated living radical polymerization (Cu0-mediated LRP) of SBMA in sodium nitrate aqueous solution instead of previously reported solvents like trifluoroethanol and sodium chloride aqueous/alcoholic solution. Based on this, starch-g-polySBMA (St-g-PSBMA) was also synthesized homogeneously by using a water-soluble waxy potato starch-based macroinitiator and CuBr/hexamethylated tris(2-aminoethyl)amine (Me6TREN) as the catalyst. The structure of the macroinitiator was characterized by 1H-NMR, 13C-NMR, gHSQC, and FT-IR, while samples of PSBMA and St-g-PSBMA were characterized by 1H-NMR and FT-IR. Monomer conversion was monitored by 1H-NMR, on the basis of which the reaction kinetics were determined. Both kinetic study and GPC results indicate reasonable controlled polymerization. Furthermore, a preliminary study of the thermal response behavior was also carried through rheological tests performed on aqueous solutions of the prepared materials. Results show that branched zwitterionic polymers are more thermal-sensitive than linear ones.

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23

Song, Xuejing, and Manfred Bochmann. "Preparation of (Cp*) {C5Me4CH2B(C6F5)3}ZrPh, a novel zwitterionic single-component alkene polymerisation catalyst." Journal of Organometallic Chemistry 545-546 (January 1997): 597–600. http://dx.doi.org/10.1016/s0022-328x(97)00389-6.

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24

Yang, Kiyull, Yih-Huang Hsieh, Chan-Kyung Kim, Hui Zhang, and Saul Wolfe. "Hydration of acetone in the gas phase and in water solvent." Canadian Journal of Chemistry 88, no. 1 (2010): 56–64. http://dx.doi.org/10.1139/v09-135.

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In water solvent, the hydration of acetone proceeds by a cyclic (cooperative) process in which concurrent C–O bond formation and proton transfer to oxygen take place through a solvent and (or) catalyst bridge. Reactivity is determined primarily by the concentration of a reactant complex and not the barrier from this complex. This situation is reversed in the gas phase; although the concentrations of reactive complexes are much higher than in solution, the barriers are also higher and dominant in determining reactivity. Calculations of isotope effects suggest that multiple hydron transfers are synchronous in the gas phase to avoid zwitterionic transition states. In solution, such transition states are stabilized by solvation and hydron transfers can be asynchronous.

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25

Yu, Zhaozhuo, Zhengyi Li, Lilong Zhang, et al. "A substituent- and temperature-controllable NHC-derived zwitterionic catalyst enables CO2 upgrading for high-efficiency construction of formamides and benzimidazoles." Green Chemistry 23, no. 16 (2021): 5759–65. http://dx.doi.org/10.1039/d1gc01897c.

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An efficient catalytic system for the construction of various formamides and benzimidazoles with good yields of up to 96% and 98% was developed using the C1 source CO2 and the stable catalyst NHC-CO2, and an interesting catalytic mechanism was reported.

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26

Marcazzan, Paolo, Brian O. Patrick, and Brian R. James. "Catalyst poisoning in catalyzed imine hydrogenation: A novel zwitterionic Rh(I)/o-hydroxy-substituted imine complex." Journal of Molecular Catalysis A: Chemical 257, no. 1-2 (2006): 26–30. http://dx.doi.org/10.1016/j.molcata.2006.04.012.

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27

Bae, Sungjun, Junyoung Jung, and Woojin Lee. "The effect of pH and zwitterionic buffers on catalytic nitrate reduction by TiO2-supported bimetallic catalyst." Chemical Engineering Journal 232 (October 2013): 327–37. http://dx.doi.org/10.1016/j.cej.2013.07.099.

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28

Zaghari, Zahra, та Javad Azizian. "Synthesis of Novel α-amidino Carboxylic Acids and their Use as H-Bond Catalysts in Strecker Reaction". Combinatorial Chemistry & High Throughput Screening 21, № 8 (2018): 609–14. http://dx.doi.org/10.2174/1386207321666181114110039.

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Aim and Objective: A wide variety of synthesized amidine derivatives are bioactive compounds. They show a vast range of medical properties. Therefore, a simple route for synthesis of novel class of amidine derivatives called amidino carboxylic acids and their use as catalysts in Strecker reaction has been reported in the current work. The stability, local charge density and hydrogen bond parameters were calculated for eight derivatives with different substituents. Materials and Methods: In order to synthesize these amidino carboxylic acids, we initially prepared Knovenogel condensation products via the reaction of isatin derivatives with malonitrile. When the reaction was performed in water, the resulting nitrile groups of malonitrile derivatives was hydrolyzed with HOAC/ H2SO4 to generate the desired amide groups. The amide groups in resulting compound converted to amine groups with two Hoffman rearrangements in the presence of NaOH/Br2. Further neutralization led to the final zwitterionic α-amidino carboxylic acids. In the next step, the catalytic activity of these compounds as H-bond donor catalyst was investigated in Strecker reaction. Results: The overall yields of the derivatives with substituent on the aromatic ring of starting isatins are higher than that for the overall yields of nitrogen-substituted isatins. The reaction of 5-nitro isatin with the next reagent gives lower yield in aryl-substituted products. An increase of catalytic activity is observed by rising the electron-withdrawing power of the aromatic ring substituents., The presence of nitro group in the structure of catalyst caused a large increase of catalytic activity in Strecker reaction. DFT calculations at B3LYP/6-31++g(d,p) and Lanl2dz level of theory showed that these compounds act as single H-bond catalysts and higher yields were obtained for complexes with stronger hydrogen bond. Conclusion: A simple and efficient method for synthesis of ɑ-amidino carboxylic acids was developed in this research. These compounds have been used as a single H-bond donor catalyst in the Strecker reaction. DFT calculations were carried out to confirm the experimental results. The obtained data from computations are in good agreement with experimental results.

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29

Barker, David, Benjamin Dickson, Nora Dittrich, and Claire E. Rye. "An acyl-Claisen approach to the synthesis of lignans and substituted pyrroles." Pure and Applied Chemistry 84, no. 7 (2012): 1557–65. http://dx.doi.org/10.1351/pac-con-11-09-27.

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The acyl-Claisen rearrangement, also called a zwitterionic aza-Claisen rearrangement, allows for the synthesis of 2,3-syn-substituted morpholine pent-4-eneamides with high levels of diastereoselectivity. A wide variety of alkyl and aryl substituents can be introduced with yields highly dependent on the stoichiometry of the Lewis acid catalyst. The use of these morpholine amides in the synthesis of the tetrasubstituted tetrahydrofuran lignans fragransin A2, talaumidin, and galbelgin is summarized. The conversion of the Claisen-derived amides into aryl tetraline and 1,1-diarylbutanol lignans via alteration of the protecting groups is also described. Nucleophilic addition of an organometallic reagent to the morpholine amide followed by Wacker oxidation of the alkene gives highly substituted 1,4-diketones, which can be easily converted into fully substituted pyrroles.

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Gulyás, H., A. Dobó, and J. Bakos. "Synthesis of sulfated mono- and ditertiary phosphines, complex chemistry and catalysis." Canadian Journal of Chemistry 79, no. 5-6 (2001): 1040–48. http://dx.doi.org/10.1139/v01-040.

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Cyclic and bicyclic sulfates have been prepared from commonly available alcohols. Nucleophilic cleavage of the cyclic sulfates affords a new type of water-soluble mono- and ditertiary phophines bearing -OSO3Li groups in distinguished positions in the molecular framework. Both phosphines have amphiphilic character. Reactions of the chiral 2 and the dppp analogue 5 with [Rh(COD)Cl]2 and Pt(PhCN)2Cl2 provide novel zwitterionic complexes. Rhodium complexes of 2 and 5 have been successfully applied in liquid biphasic hydroformylation of styrene and octene-1. When the rhodium complex of 5 was used as catalyst in hydroformylation of styrene, less then 4 ppm rhodium could be detected in the organic phase.Key words: cyclic sulfates, water soluble phosphines, amphiphilic character, Rh complexes, Pt complexes, hydroformylation.

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31

Park, H. S., E. Alberico, and H. Alper. "Regio- and Stereoselective Synthesis of Key 1-Methyl Carbapenem Intermediates via Hydroformylation Using a Zwitterionic Rhodium Catalyst." Journal of the American Chemical Society 121, no. 50 (1999): 11697–703. http://dx.doi.org/10.1021/ja993080j.

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32

Lücke, Ana-Luiza, Sascha Wiechmann, Tyll Freese, Zong Guan, and Andreas Schmidt. "Palladium complexes of anionic N-heterocyclic carbenes derived from sydnones in catalysis." Zeitschrift für Naturforschung B 71, no. 6 (2016): 643–50. http://dx.doi.org/10.1515/znb-2016-0006.

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AbstractThe anion of N-phenylsydnone, which can be generated on treatment of N-phenylsydnone with cyanomethyllithium without decomposition, can be represented as tripolar zwitterionic and as anionic N-heterocyclic carbene resonance forms. Its palladium complex was prepared from 4-bromo-3-phenylsydnone and tetrakis(triphenylphosphine)palladium and proved to be active as catalyst in Suzuki-Miyaura reactions. Thus, 2,5-dibromo-3,4-dinitrothiophene was effectively converted into 2,5-diaryl-3,4-dinitrothiophenes with 1-naphthyl, (4-trifluoromethoxy)phenyl, [4-(methylsulfanyl)phenyl], and biphenyl-4-yl boronic acid. 3-(Phenanthren-9-yl)quinoline was prepared by Suzuki-Miyaura reaction starting from 3-bromoquinoline. 1-Chloro-2,4-dinitrobenzene cross-coupled with phenyl boronic acid, 1-naphthyl boronic acid, 9-phenanthryl boronic acid. 4-Bromobenzylic alcohol gave (4-isopropylphenyl)methanol on sydnone-palladium complex-catalyzed reaction with isopropyl boronic acid.

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33

Mayank, Mayank, Amanpreet Singh, Pushap Raj, et al. "Zwitterionic liquid (ZIL) coated CuO as an efficient catalyst for the green synthesis of bis-coumarin derivatives via one-pot multi-component reactions using mechanochemistry." New Journal of Chemistry 41, no. 10 (2017): 3872–81. http://dx.doi.org/10.1039/c6nj03763a.

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ZIL@CuO1–3 were developed as a catalyst for the synthesis of bis-coumarins under environmentally benign conditions. Mechanochemistry induced synthesis of bis-coumarin derivatives with more than 90% yield was accomplished.

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34

Boßmann, Stefan, Heinz Dürr, and Eduard Mayer. "Biomimetische Photosysteme zur sakrifiziellen Wasserreduktion / Novel Biomimetic Systems for Visible Light Induced Water Reduction." Zeitschrift für Naturforschung B 48, no. 3 (1993): 369–86. http://dx.doi.org/10.1515/znb-1993-0317.

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Novel microheterogeneous systems for the direct photoreduction of water using visible light in analogy to the photochemical reaction center of Rhodopseudomonas viridis are described in detail. These physical model systems for photosynthesis feature the recently synthesized bisheteroleptic metal complexes [Ru(bpy)2(PP)]Cl2, [Ru(bpy)2(PPB)]Cl2, [Ru(bpy)2(PPB-pCl)]Cl2 and [Ru(bpy)3]Cl2, adsorbed on a negatively charged SiO2—TiO2-colloid, the zwitterionic electron relay PVS and a long-term stable and highly efficient TiO2—Pt-“antenna” catalyst as well as TEOA as sacrificial electron donor.Evidence for the directed absorption of the sensitizers on the SiO2—TiO2-colloid is taken from UV-VIS-measurements, steady-state luminescence-spectroscopy and the quantum yields for PVS-reduction.The hydrogen production in the presence of the SiO2—TiO2-colloid is clearly enhanced and proofs the validity of the underlying concept of physical model systems for photosynthesis.

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35

Strauch, Joachim W., Gerhard Erker, Gerald Kehr, and Roland Fröhlich. "Formation of a Butadienenickel-Based Zwitterionic Single-Component Catalyst for Ethylene Polymerization: An Alternative Activation Pathway for Homogeneous Ziegler-Natta Catalysts of Late Transition Metals." Angewandte Chemie International Edition 41, no. 14 (2002): 2543–46. http://dx.doi.org/10.1002/1521-3773(20020715)41:14<2543::aid-anie2543>3.0.co;2-w.

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36

Park, H. S., E. Alberico, and H. Alper. "ChemInform Abstract: Regio- and Stereoselective Synthesis of Key 1-Methyl Carbapenem Intermediates via Hydroformylation Using a Zwitterionic Rhodium Catalyst." ChemInform 31, no. 12 (2010): no. http://dx.doi.org/10.1002/chin.200012063.

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37

Wanapun, D., K. A. Van Gorp, N. J. Mosey, M. A. Kerr, and T. K. Woo. "The mechanism of 1,3-dipolar cycloaddition reactions of cyclopropanes and nitrones A theoretical study." Canadian Journal of Chemistry 83, no. 10 (2005): 1752–67. http://dx.doi.org/10.1139/v05-182.

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The 1,3-dipolar cycloaddition reaction of cyclopropanes and nitrones to give tetrahydro-1,2-oxazine has been studied with density functional theory calculations at the B3LYP/6-31+G(d,p) level of theory. Realistic substituents were modelled including those at the 2-, 3-, 4-, and 6-positions of the final oxazine ring product. The strained σ bond of the cyclopropane was found to play the role of an alkene in a conventional [3+2] dipolar cycloaddition. Two distinct, but similar, reaction mechanisms were found an asymmetric concerted pathway and a stepwise zwitterionic pathway. The reaction barriers of the two pathways were nearly identical, differing by less than ~1 kcal/mol, no matter what the substituents were. The effect of a Lewis acid catalyst was examined and found to have a very large effect on the calculated barriers through coordination to the carbonyl oxygen atoms of the diester substituents on the cyclopropane. The reaction barrier was found to decrease by as much as ~19 kcal/mol when using a BF3 molecule as a model for the Lewis acid catalyst. Solvent effects and the nature of the regiospecificity of the reaction were also examined. Trends in the calculated barriers for the reaction were in good agreement with available trends in the reaction rates measured experimentally. Key words: 1,3-dipolar cycloaddition, cyclopropane, nitrone, tetrahydro-1,2-oxazines, ab initio quantum chemistry, mechanism.

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38

Arlegui, Aitor, Zoubir El-Hachemi, Joaquim Crusats, and Albert Moyano. "5-Phenyl-10,15,20-Tris(4-sulfonatophenyl)porphyrin: Synthesis, Catalysis, and Structural Studies." Molecules 23, no. 12 (2018): 3363. http://dx.doi.org/10.3390/molecules23123363.

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A convenient protocol for the preparation of 5-phenyl-10,15,20-tris(4-sulfonatophenyl)porphyrin, a water-soluble porphyrin with unique aggregation properties, is described. The procedure relies on the one-pot reductive deamination of 5-(4-aminophenyl)-10,15,20-tris(4-sulfonatophenyl)porphyrin, that can be in turn easily obtained from 5,10,15,20-tetraphenylporphyrin by a known three-step sequence involving mononitration, nitro to amine reduction and sulfonation of the phenyl groups. This method provides the title porphyrin in gram scale, and compares very favorably with the up to now only described procedure based on the partial sulfonation of TPP, that involves a long and tedious chromatographic enrichment of the final compound. This has allowed us to study for the first time both the use of its zwitterionic aggregate as a supramolecular catalyst of the aqueous Diels–Alder reaction, and the morphology of the aggregates obtained under optimized experimental conditions by atomic force microscopy and also by transmission electron cryomicroscopy.

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39

Oh, Jung, Jung, and Khan. "A Modular and Practical Synthesis of Zwitterionic Hydrogels through Sequential Amine-Epoxy “Click” Chemistry and N-Alkylation Reaction." Polymers 11, no. 9 (2019): 1491. http://dx.doi.org/10.3390/polym11091491.

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In this work, the amine-epoxy “click” reaction is shown to be a valuable general tool in the synthesis of reactive hydrogels. The practicality of this reaction arises due to its catalyst-free nature, its operation in water, and commercial availability of a large variety of amine and epoxide molecules that can serve as hydrophilic network precursors. Therefore, hydrogels can be prepared in a modular fashion through a simple mixing of the precursors in water and used as produced (without requiring any post-synthesis purification step). The gelation behavior and final hydrogel properties depend upon the molecular weight of the precursors and can be changed as per the requirement. A post-synthesis modification through alkylation at the nitrogen atom of the newly formed β-hydroxyl amine linkages allows for functionalizing the hydrogels. For example, ring-opening reaction of cyclic sulfonic ester gives rise to surfaces with a zwitterionic character. Finally, the established gelation chemistry can be combined with soft lithography techniques such as micromolding in capillaries (MIMIC) to obtain hydrogel microstructures.

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40

Bahsis, Lahoucine, Meryem Hrimla, Hicham Ben El Ayouchia, Hafid Anane, Miguel Julve, and Salah-Eddine Stiriba. "2-Aminobenzothiazole-Containing Copper(II) Complex as Catalyst in Click Chemistry: An Experimental and Theoretical Study." Catalysts 10, no. 7 (2020): 776. http://dx.doi.org/10.3390/catal10070776.

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The reaction of copper(II) acetate with the 2-aminobenzothiazole (abt) heterocycle affords the new copper(II) complex of formula [Cu(abt)2(OOCCH3)2] (1) in a straightforward manner. Compound 1 served as a precatalyst for azide/alkyne cycloaddition reactions (CuAAC) in water, leading to 1,4-disubstituted-1,2,3-triazole derivatives in a regioselective manner and with excellent yields at room temperature. The main advantages of the coordination of such a heterocyclic ligand in 1 are its strong σ-donating ability (N-Cu), nontoxicity and biological properties. In addition, the click chemistry reaction conditions using 1 allow the formation of a great variety of 1,2,3-triazole-based heterocyclic compounds that make this protocol potentially relevant from biological and sustainable viewpoints. A molecular electron density theory (MEDT) study was performed by using density functional theory (DFT) calculations at the B3LYP/6-31G(d,p) (LANL2DZ for Cu) level to understand the observed regioselectivity in the CuAAC reaction. The intramolecular nature of this reaction accounts for the regioselective formation of the 1,4-regioisomeric triazole derivatives. The ionic nature of the starting copper-acetylide precludes any type of covalent interaction throughout the reaction, as supported by the electron localization function (ELF) topological analysis, reaffirming the zwitterionic-type (zw-type) mechanism of the copper(I)/aminobenzothiazole-catalysed azide-alkyne cycloaddition reactions.

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Chen, Xia, Xu Ye, Wen-Yu Liang, Qing Zhou, Giang Vo-Thanh, and Ye Liu. "Amphiphilic Zwitterionic phosphine based Au(I)-complex as efficient and recyclable catalyst for hydration of alkynes free of additional additives." Molecular Catalysis 448 (April 2018): 171–76. http://dx.doi.org/10.1016/j.mcat.2018.01.035.

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42

Weerasiri, Kushan C., Danmin Chen, Derek I. Wozniak, and Graham E. Dobereiner. "Internal Alkyne Regio- and Chemoselectivity using a Zwitterionic N-Heterocyclic Carbene Gold Catalyst in a Silver-Free Alkyne Hydration Reaction." Advanced Synthesis & Catalysis 358, no. 24 (2016): 4106–13. http://dx.doi.org/10.1002/adsc.201601013.

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43

Sun, Yimin, Rupert E. v. H. Spence, Warren E. Piers, Masood Parvez, and Glenn P. A. Yap. "Intramolecular Ion−Ion Interactions in Zwitterionic Metallocene Olefin Polymerization Catalysts Derived from “Tucked-In” Catalyst Precursors and the Highly Electrophilic Boranes XB(C6F5)2(X = H, C6F5)." Journal of the American Chemical Society 119, no. 22 (1997): 5132–43. http://dx.doi.org/10.1021/ja970140h.

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44

Vogel, Pierre, Maris Turks, Laure Bouchez, et al. "Use of sultines in the asymmetric synthesis of polypropionate antibiotics." Pure and Applied Chemistry 80, no. 4 (2008): 791–805. http://dx.doi.org/10.1351/pac200880040791.

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At low temperature and in the presence of an acid catalyst, SO2 adds to 1,3-dienes equilibrating with the corresponding 3,6-dihydro-1,2-oxathiin-2-oxides (sultines). These compounds are unstable above -60 °C and equilibrate with the more stable 2,5-dihydrothiophene 1,1-dioxides (sulfolenes). The hetero-Diels-Alder additions of SO2 are suprafacial and follow the Alder endo rule. The sultines derived from 1-oxy-substituted and 1,3-dioxy-disubstituted 1,3-dienes cannot be observed at -100 °C but are believed to be formed faster than the corresponding sulfolenes. In the presence of acid catalysts, the 6-oxy-substituted sultines equilibrate with zwitterionic species that react with electron-rich alkenes such as enoxysilanes and allylsilanes, generating β,γ-unsaturated silyl sulfinates that can be desilylated and desulfinylated to generate polypropionate fragments containing up to three contiguous stereogenic centers and an (E)-alkene unit. Alternatively, the silyl sulfinates can be reacted with electrophiles to generate polyfunctional sulfones (one-pot, four-component synthesis of sulfones), or oxidized into sulfonyl chlorides and reacted with amines, then realizing a one-pot, four-component synthesis of polyfunctional sulfonamides. Using enantiomerically enriched dienes such as 1-[(R)- or 1-(S)-phenylethyloxy]-2-methyl-(E,E)-penta-1,3-dien-3-yl isobutyrate, derived from inexpensive (R)- or (S)-1-phenylethanol, enantiomerically enriched stereotriads are obtained in one-pot operations. The latter are ready for further chain elongation. This has permitted the development of expeditious total asymmetric syntheses of important natural products of biological interest such as the baconipyrones, rifamycin S, and apoptolidin A.

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45

Stoelzel, Miriam, Carsten Präsang, Burgert Blom, and Matthias Driess. "N-Heterocyclic Silylene (NHSi) Rhodium and Iridium Complexes: Synthesis, Structure, Reactivity, and Catalytic Ability." Australian Journal of Chemistry 66, no. 10 (2013): 1163. http://dx.doi.org/10.1071/ch13196.

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Reaction of the zwitterionic N-heterocyclic silylene (NHSi) 1 L′Si: (L′ = [HC(CMeNAr)(C(CH2)NAr)], Ar = 2,6-iPr2C6H3) with HCl at low temperatures affords the kinetically stable 1,4-addition product of 1, LSiCl (L = [HC(CMeNAr)2], Ar = 2,6-iPr2C6H3) (9a), which upon reaction with [Rh(Cl)cod]2 and [Ir(Cl)cod]2 (cod = 1,5-cyclooctadiene) selectively affords the NHSi complexes [L(Cl)Si:→Rh(Cl)cod] (10a) and [L(Cl)Si:→Ir(Cl)cod] (10b), respectively. The latter were employed as pre-catalysts in the catalytic reduction of amides in the presence of silanes. Remarkably, they show strikingly different activities and selectivities. While complex 10a yields selectively the C–O cleavage product, 10b affords both cleavage products (C–O and C–N). Moreover, the total conversion of the catalytic amide reduction with 10b is significantly higher than the conversion with a benchmark system [Ir(Cl)cod]2 highlighting the enhanced catalytic activity afforded by the coordination of the NHSi ligand. Introducing the hydride source Li[HBEt3] into the catalytic reactions retards the catalyst performance due to a competitive decomposition pathway. This appears to occur via a H-shift onto the cod ligand with concomitant liberation of cyclooctene, which is also presented. The different reactivity of 10a and 10b towards nucleophiles such as MeLi is also discussed. The reaction of 10a with MeLi affords an intractable array of products, while the reaction of 10b with one equivalent of MeLi selectively affords [L(Cl)Si:→Ir(CH3)cod] (14) with selective methylation at the Ir centre. The analogous reaction with two equivalents of 10b affords the double methylated product [L(CH3)Si:→Ir(CH3)cod] (15).

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46

Bagherzadeh, Mojtaba, Hamed Mahmoudi, Saeed Ataie, et al. "Synthesis and characterization of a new zwitterionic palladium complex as an environmentally friendly catalyst for the Heck-Mizoroki coupling reaction in GVL." Molecular Catalysis 474 (September 2019): 110406. http://dx.doi.org/10.1016/j.mcat.2019.110406.

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47

Lundgren, Rylan J, Matthew A Rankin, Robert McDonald, Gabriele Schatte, and Mark Stradiotto. "A Formally Zwitterionic Ruthenium Catalyst Precursor for the Transfer Hydrogenation of Ketones that Does Not Feature an Ancillary Ligand NH Functionality." Angewandte Chemie International Edition 46, no. 25 (2007): 4732–35. http://dx.doi.org/10.1002/anie.200700345.

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48

Lundgren, Rylan J, Matthew A Rankin, Robert McDonald, Gabriele Schatte, and Mark Stradiotto. "A Formally Zwitterionic Ruthenium Catalyst Precursor for the Transfer Hydrogenation of Ketones that Does Not Feature an Ancillary Ligand NH Functionality." Angewandte Chemie 119, no. 25 (2007): 4816–19. http://dx.doi.org/10.1002/ange.200700345.

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49

Ojeda‐Amador, Ana I., Julen Munarriz, Pablo Alamán‐Valtierra, et al. "Mechanistic Insights on the Functionalization of CO 2 with Amines and Hydrosilanes Catalyzed by a Zwitterionic Iridium Carboxylate‐Functionalized Bis‐NHC Catalyst." ChemCatChem 11, no. 22 (2019): 5524–35. http://dx.doi.org/10.1002/cctc.201901687.

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50

Schwan, Adrian L., and John Warkentin. "The reactions of simple dimethylallylamines with dimethyl acetylenedicarboxylate. Formation of 1-dimethylamino-2-allylmaleates via formal allyl transfer." Canadian Journal of Chemistry 66, no. 7 (1988): 1686–94. http://dx.doi.org/10.1139/v88-273.

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Tertiary amines bearing two methyl groups and an allylic substituent (X) react with dimethyl acetylenedicarboxylate (DMAD) to afford the corresponding 1-dimethylamino-2-X′ maleates, in which X′ is the allylic isomer of X. The mechanism postulated involves reversible formation of a zwitterion by attack of the amine at an sp-carbon of DMAD. The zwitterion then undergoes intramolecular allyl transfer, through a 6-membered transition state. Evidence for a zwitterionic intermediate (quaternary ammonium allenolate) includes capture of the allenolate centre by intramolecular addition to a carbonyl group and by proton transfer from chloroform.

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