- Amino acid-derived N-heterocyclic carbene palladium complexes for aqueous phase Suzuki-Miyaura couplings
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In this work, three ligands produced from amino acids were synthesized and used to produce five bis- and PEPPSI-type palladium-NHC complexes using a novel synthesis route from sustainable starting materials. Three of these complexes were used as precatalysts in the aqueous-phase Suzuki-Miyaura coupling of various substrates displaying high activity. TEM and mercury poisoning experiments provide evidence for Pd-nanoparticle formation stabilized in water.
- Steeples, Elliot,Kelling, Alexandra,Schilde, Uwe,Esposito, Davide
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- Molecular structure of 1,3-bis(carboxymethyl)imidazolium bromide and its betaine form in crystal
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1,3-Bis(carboxymethyl)imidazolium bromide [(C7H9N2O4)+Br-] has been studied by X-ray diffraction, FT-IR and Raman spectroscopy. In the crystalline state, two 1,3-bis(carboxymethyl)imidazolium bromide molecules are hydrogen-bonded via carboxylic groups forming a symmetric dimer. Within the dimer structure the other carboxylic groups are hydrogen bonded to Br- anions. Both types of intermolecular hydrogen bonds are the relatively weak. In the solid state the Br- anions interact with both ring and with the aliphatic C-H protons. Furthermore, the betaine derivative form in the solid state a chain via strong homoconjugated (O-H···O)- hydrogen bonds. The nature of these hydrogen bonds is well reflected by the proton vibrations in the FT-IR spectra of the compounds studied. As follows from the ESI-MS results the compounds studied are not able to complex mono- and di-valent metal cations in the gas phase.
- Barczyński, Piotr,Komasa, Anna,Ratajczak-Sitarz, Ma?gorzata,Katrusiak, Andrzej,Huczyński, Adam,Brzezinski, Bogumil
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- Amino acid based imidazolium zwitterions as novel and green corrosion inhibitors for mild steel: Experimental, DFT and MD studies
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Three novel amino acids based corrosion inhibitors namely 2-(3-(carboxymethyl)-1H-imidazol-3-ium-1-yl)acetate (AIZ-1), 2-(3-(1-carboxyethyl)-1H-imidazol-3-ium-1-yl)propanoate (AIZ-2) and 2-(3-(1-carboxy-2-phenylethyl)-1H-imidazol-3-ium-1-yl)-3-phenylpropa
- Srivastava,Haque, Jiyaul,Verma,Singh,Lgaz,Salghi,Quraishi
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- Synthesis, structure and luminescence of lanthanide coordination polymers based on the 1,3-Bis(carboxymethyl) imidazolium salt
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The 1,3-bis(carboxymethyl)imidazolium salt (zwitterion) (HBCI) was reacted, under solvothermal conditions, with rare earth chlorides to provide a series of new two-dimensional (2D) coordination polymers, namely [LnBCI) (HCOO) (H2O)2Cl]n [Ln = Sm (1); Eu (2); Gd (3); Tb (4); Dy (5)]. The complexes were characterized by X-ray single crystal diffraction, powder X-ray diffraction, infrared spectroscopy, elemental analysis and thermogravimetric analysis. Compounds of 1, 2, 4 and 5 exhibit the characteristic luminescence of the corresponding lanthanide ions, due to the 4fn-4fn transition. Furthermore, the fluorescence lifetime of 2 and the phosphorescence spectrum of 5 at 77k are discussed.
- You, Li-Xin,Guo, Yang,Xie, Shi-Yu,Wang, Shu-Ju,Xiong, Gang,Dragutan, Ileana,Dragutan, Valerian,Ding, Fu,Sun, Ya-Guang
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- Synthesis and characterization of Au(I) and Au(III) complexes containing N-heterocyclic ligands derived from amino acids
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A series of [Au(NHC)2] (1a–4a) complexes supported by NHC ligands derived from glycine, alanine, methionine and phenylalanine (1–4 respectively) were prepared via a direct transmetalation reaction of their respective silver complexes. The Au complexes were characterized by ESI-MS and NMR spectroscopy in solution. These compounds exhibit instability when the solvent is removed; they displayed a strong tendency to form colored solutions in the order 4a > 3a?> 2a > 1a, which is associated with gold nanoparticles. 1a and 2a undergo oxidative addition of elemental bromine, yielding [Au(NHC)2Br2] (1b) for 1a and a mixture of [Au(NHC)2Br2] (2b) and [Au(NHC)Br3] (2c) for 2a. 2b and 2c were characterized by single crystal X-ray diffraction.
- Alvarado-Rodríguez, José G.,Cortes-Llamas, Sara A.,Espinosa-Macías, María L.,López-Dellamary-Toral, Fernando A.,Manríquez-González, Ricardo,Peregrina-Lucano, A. Aarón,Rangel-Salas, Irma I.,Reynoso-Esparza, Mario A.
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- Magnetostructural J-correlations in complexes with tetrahedro-{Cu 4} core
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A comprehensive analysis of structural and magnetic data for 41 tetrahedro-{Cu4} complexes reveals that the exchange coupling constants (J2 and J4) correlate with averaged structural parameters of which the most informative are the averaged Cu-O-Cu angles in the bases (β) and walls (α) of the cubane structure. Using contemporary statistical programs, the cluster analysis, the principal component analysis, and the factor analysis bring information about the possible correlations of the magnetic and structural parameters and grouping of the parameters according to their similarity.
- Makohusová,Mrázová,Haase,Bo?a
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- Bronsted acidic ionic liquids and their zwitterions: Synthesis, characterization and pKa determination
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Imidazolium chlorides with one or two carboxylic acid substituent groups, 1-methyl-3-alkylcarboxylic acid imidazolium chloride, [Me{(CH2) nCOOH}im]Cl (n = 1, 3), and 1,3-dialkylcarboxylic acid imidazolium chloride, [{(CH2)nCOOH}2im]Cl (n = 1, 3), have been synthesized via their corresponding acid esters. Deprotonation of the carboxylic acid functionalized imidazolium chlorides with triethylamine affords the corresponding zwitterions [Me{(CH2)nCOO}im] (n = 1, 3) and [{(CH2)nCOOH}{(CH2)nCOO}im] (n = 1, 3). Subsequent reaction of the zwitterions with strong acids gives the new imidazolium salts [Me{(CH2)nCOOH}im]X (n = 1, 3; X = BF4, CF3SO3) and [{(CH2) nCOOH}2im]X (n = 1, 3; X = BF4, CF 3SO3), which exhibit melting points as low as -61°C. The solid-state structures of two of the carboxylic acid functionalized imidazolium salts have been determined by single-crystal X-ray diffraction analysis. Extensive hydrogen bonding is present between the chloride and the imidazolium, with eight Cl ··H interactions below 3 A. The pKa values of all the salts, determined by potentiometric titration, lie between 1.33 and 4.59 at 25°C.
- Fei, Zhaofu,Zhao, Dongbin,Geldbach, Tilmann J.,Scopelliti, Rosario,Dyson, Paul J.
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- Anion-Dependent Imidazolium-Based Catalysts for Allylation of Aniline with Tunable Regioselectivity
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Metal-free catalysts based on 1,3-bis(carboxymethyl)imidazolium halides mediate the reaction between allylic alcohols and anilines, providing the corresponding N-, 2- and 4-allylaniline isomers selectively. The imidazolium counterion plays a crucial role
- Albert-Soriano, María,M. Pastor, Isidro
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supporting information
p. 2494 - 2502
(2020/04/29)
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- “Doubly Orthogonal” Labeling of Peptides and Proteins
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Herein, we report a cysteine bioconjugation methodology for the introduction of hypervalent iodine compounds onto biomolecules. Ethynylbenziodoxolones (EBXs) engage thiols in small organic molecules and cysteine-containing peptides and proteins in a fast and selective addition onto the alkynyl triple bond, resulting in stable vinylbenziodoxolone hypervalent iodine conjugates. The conjugation occurs at room temperature in an open flask under physiological conditions. The use of an azide-bearing EBX reagent enables a “doubly orthogonal” functionalization of the bioconjugate via strain-release-driven cycloaddition and Suzuki-Miyaura cross-coupling of the vinyl hypervalent iodine bond. We successfully applied the methodology on relevant and complex biomolecules, such as histone proteins. Through single-molecule experiments, we illustrated the potential of this doubly reactive bioconjugate by introducing a triplet-state quencher close to a fluorophore, which extended its lifetime by suppressing photobleaching. This work is therefore expected to find broad applications for peptide and protein functionalization. Understanding the molecular basis of life is essential in the search for new medicines. Chemical biology develops molecular tools for studying biological processes, setting the basis for new diagnostics and therapeutics, and relies heavily on the ability to selectively modify biomolecules. Two approaches have been especially fruitful: (1) selective modification of natural biomolecules and (2) selective reaction between non-natural functionalities in the presence of biomolecules (the so-called orthogonal bioconjugation). In our work, we contribute to both by transferring highly reactive hypervalent iodine reagents to cysteine residues in proteins and peptides. The obtained bioconjugates retain the reactive hypervalent bonds, which can be selectively functionalized via a metal-mediated reaction. Combined with a traditional azide tag, our approach allows a doubly orthogonal functionalization of biomolecules and is hence expected to be highly useful in chemical biology. Chemical biology develops molecular tools for studying biological processes, setting the basis for new diagnostics and therapeutics, and relies heavily on the ability to modify selectively biomolecules. In our work, we introduce hypervalent iodine bonds into peptides and proteins, via functionalization of cysteine, by using unique cyclic reagents developed in our group. The hypervalent bond can then be selectively modified in the presence of both natural and synthetic functional groups, opening new opportunities for applications in chemical biology.
- Tessier, Romain,Ceballos, Javier,Guidotti, Nora,Simonet-Davin, Raphael,Fierz, Beat,Waser, Jerome
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supporting information
p. 2243 - 2263
(2019/08/08)
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- Versatile Barium and Calcium Imidazolium-Dicarboxylate Heterogeneous Catalysts in Quinoline Synthesis
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This article details the development of heterogeneous catalysts based on calcium and barium in combination with the organic linker 1,3-bis(carboxymethyl)imidazolium (bcmim). The linker and the materials from alkaline earth metals are easily prepared under very smooth conditions. The use of linkers with different counterions (Cl or Br) provided different materials. Calcium- and barium-based catalysts were successfully employed in the preparation of quinoline derivatives from ketones and 2-aminoarylaldehydes or 2-aminoarylketones. In general, barium-based catalysts provided better results than calcium, although the latter are an excellent complement for certain substrates. Thus, a notable feature of such catalysts is the possibility of accessing a variety of complementary heterogeneous catalytic systems, rendering the catalysis adaptive to the reactant.||||||.
- Albert-Soriano, María,Trillo, Paz,Soler, Tatiana,Pastor, Isidro M.
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supporting information
p. 6375 - 6381
(2017/12/01)
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- Metal–Organic Framework Based on Copper and Carboxylate-Imidazole as Robust and Effective Catalyst in the Oxidative Amidation of Carboxylic Acids and Formamides
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A metal–organic framework (MOF) based on copper and 1,3-bis(carboxymethyl)imidazole (bcmim) was prepared on a gram scale by using a precipitation method at room temperature. The Cu(bcmim)2MOF was shown to be an efficient catalyst for the preparation of amides through an oxidative coupling between carboxylic acids and formamides in the presence of an oxidant, such as tert-butyl hydroperoxide (TBHP). The method for the preparation of the amides is robust regardless of the carboxylic acid and gives good conversions with good selectivity. The heterogeneous catalyst was recovered unaltered after the reaction, was easily separated from the reaction mixture, and subsequently reactivated by suitable treatment. Moreover, the coupling reaction was scaled up to a gram scale, which allowed for the preparation of valuable products, such as fatty acid amides (i.e., 1-palmitoylpiperidine).
- Albert-Soriano, María,Pastor, Isidro M.
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supporting information
p. 5180 - 5188
(2016/10/26)
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- Hydrothermal decarboxylation of amino acid derived imidazolium zwitterions: A sustainable approach towards ionic liquids
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Ionic liquids were prepared via hydrothermal decarboxylation of zwitterionic imidazolium compounds derived from amino acids and carbohydrate related dicarbonyl compounds. Two of these ionic liquids were used successfully as solvents in the Heck reaction a
- Kirchhecker, Sarah,Antonietti, Markus,Esposito, Davide
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supporting information
p. 3705 - 3709
(2014/08/05)
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- Imidazolium salts from amino acids-a new route to chiral zwitterionic carbene precursors?
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Chiral, carboxylic acid-functionalised imidazolium zwitterions were synthesised from the corresponding l-amino acids phenyl alanine, alanine and glycine (achiral). They form infinite C11 (10) chain structures in the solid state. The incorporation of water is dependent upon the creation of suitable cavities by the steric demands of the amino acid side chains.
- Kuehl, Olaf,Palm, Gottfried
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experimental part
p. 393 - 397
(2010/07/02)
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