26 results on '"Au(I)"'
Search Results
2. Modulating the carbon chain length of organic phosphine for the selective Au(I) recovery from a copper-ammonia-thiosulfate leaching solution
- Author
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Li, Xinrong, Chen, Shuliang, Dai, Zihui, Hu, Xianzhi, and Zi, Futing
- Published
- 2024
- Full Text
- View/download PDF
3. Efficient and sustainable recovery of Au(I) from thiosulfate solution by tri-n-butylphosphine functionalized chitosan microspheres with abundant pores
- Author
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Li, Xinrong, Chen, Shuliang, Hu, Xianzhi, and Zi, Futing
- Published
- 2024
- Full Text
- View/download PDF
4. Constructing phosphine-containing microspheres for selective recovery of gold(I) thiosulfate complex by adjusting the interaction site
- Author
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Chen, Shuliang, Yang, Yuxin, Zi, Futing, Hu, Xianzhi, and Li, Xinrong
- Published
- 2025
- Full Text
- View/download PDF
5. Oxidation State and Halogen Influence on the NHC‐Gold‐Halide‐Catalyzed Cyclization of Propargylic Amides.
- Author
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Sargentoni, Nicola, Galassi, Rossana, Luciani, Lorenzo, Rominger, Frank, Rudolph, Matthias, and Hashmi, A. Stephen. K.
- Subjects
- *
GOLD catalysts , *OXIDATION states , *GOLD compounds , *SILVER salts , *NUCLEAR magnetic resonance spectroscopy - Abstract
The homogeneously catalyzed cycloisomerization reaction of propargylic amides was tested as benchmark reaction for two homologous series of Au(I) and Au(III) complexes with NHC ligands. This reaction is known to afford either aromatic oxazoles or dihydrooxazoles, depending on the oxidation state of the applied gold catalysts. For this purpose, symmetric and unsymmetric NHC ligands with mixed alkyl or benzyl substituents (1,3‐dimethyl‐imidazolyl‐2yl or 1‐benzyl‐3‐methyl‐imidazolyl‐2‐yl) and the corresponding Au(I) and Au(III) derivatives were prepared and characterized by analytical methods, IR and 1H and 13C NMR spectroscopies, and by X‐ray diffraction methods. Ten NHC‐gold(I) and NHC‐gold(III) complexes were tested on the cyclization reactions by adding gold catalysts in the presence and absence of AgPF6. Noteworthy, only the 1‐benzyl‐3‐methyl‐gold(III) trichloride was able to give selectively the aromatic oxazole without the addition of the silver salt. Interestingly, on contrary to what is reported in the literature, the use of gold(I) or gold(III) complexes does not influence the chemoselectivity of the cyclization reaction, while the halide bound to the metal does. In this regard, a mechanism purposing the dihydrooxazole as an intermediate for the formation of aromatic oxazole is proposed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. A DFT study on the reaction mechanism of the gold(I)‐catalyzed cycloisomerization of alkynylhydroxyallylamides to 4‐Oxa‐6‐azatricyclo[3.3.0.02,8]octane and 3‐Acyl‐4‐alkenylpyrrolidine.
- Author
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Jung, Daero and Kang, Youn K.
- Subjects
- *
CYCLOISOMERIZATION , *OCTANE , *DENSITY functional theory , *ACTIVATION energy , *HIGH temperatures - Abstract
In this study, we use density functional theory calculations to investigate the discrepancy between two experimental results of Au(I)‐catalyzed cycloisomerization reactions of alkynylhydroxyallyl tosylamide under similar reaction conditions, with the only variations being reaction temperature and time. The experimental results reported by Yeh and Chung groups, respectively, showed that 3‐acyl‐4‐alkenylpyrrolidines are produced dominantly at ambient temperature, while 4‐aza‐6‐oxatricyclo[3.3.0.02,8]octanes are produced in higher yield at elevated temperature. Using (Z)‐4‐([3‐phenylprop‐2‐yn‐1‐yl]amino)but‐2‐en‐1‐ol and [Au(PPh3)]+ as the model starting material and active catalyst species, respectively, we identified two major pathways leading to 4‐aza‐6‐oxatricyclo[3.3.0.02,8]octane (pathway I) and 3‐acyl‐4‐alkenylpyrrolidine (pathway II). The overall free energy barrier (ΔG‡max) and the energetic span (ΔG‡span) of each pathway were 38.3 and 48.4 kcal/mol for pathway I and 29.0 and 37.1 kcal/mol for pathway II. Our analysis shows that the disparate outcomes observed in the experiments by two separate groups mainly originate in the reaction kinetics, with both the overall activation barrier and energetic span being the important factor. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
7. Synergistic extraction of gold(I) from aurocyanide solution with the mixture of primary amine N1923 and bis(2-ethylhexyl) sulfoxide in supported liquid membrane.
- Author
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Yang, Xiangjun, Zhang, Qin, Wang, Ziyue, Li, Shengjian, Xie, Qiying, Huang, Zhangjie, and Wang, Shixiong
- Subjects
- *
POLYVINYLIDENE fluoride , *POLYMERIC membranes , *GOLD , *METAL cyanides , *PERMEABILITY , *DIFFUSION , *SULFOXIDES synthesis - Abstract
Utilization of supported liquid membrane (SLM) for the extraction of Au(I) from alkaline cyanide solution was investigated. The SLM consisted of a synergistic mixture of primary amine N1923 and bis(2-ethylhexyl) sulfoxide (BESO) in kerosene as carrier and a hydrophobic microporous polyvinylidene fluoride (PVDF) membrane as the solid support. The presence of both BESO and N1923 extractants in the liquid membrane induces an evident synergistic effect, allowing the latter to transfer Au(I) from the highly alkaline solution (pH>9.21). The fundamental parameters influencing the gold transport, such as stirring speed, composition of the liquid membrane, feed pH, NaOH concentration in stripping solution, and initial gold concentration in the feed solution were explored. The gold transport is almost quantitative after 7 h under the optimum process conditions: a mixture of (0.50 mol/L N1923 + 0.75 mol/L BESO) in kerosene as membrane phase, stirring rate of 1000 rpm in both phases, 5.0 mg/L gold in 0.20 mol/L NaCl solution with a pH of 9.60, and 0.10 mol/L NaOH as stripping agent. The parameters defining the mass transfer model of Au(I) through the SLM are experimentally determined as: maximum permeability coefficient, P = 31.45 × 10 −6 m/s, the diffusion coefficient for [Au(CN) 2 − ·RNH 3 + ·2BESO] complex across the liquid membrane, D org = 1.42 × 10 –12 m 2 /s, and the thickness of the aqueous diffusion layer, d aq = 2.07 × 10 −5 m. Selectivity of this SLM system was evaluated by performing the permeation test of Au(CN) 2 - with other metal cyanide species in aqueous solution and it was found that the gold ions were preferred over other impurity ones. Finally, stability of this SLM system has also been examined on a continuous run mode and satisfactory stability was observed for five runs. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
8. Extraction of Au(I) from aurocyanide solution by using a synergistic system of primary amine N1923/bis(2-ethylhexyl) sulfoxide: A mechanism study.
- Author
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Yang, Xiangjun, Yuan, Xiaohong, Duan, Hengpan, Huang, Rong, Huang, Zhangjie, Guo, Hong, and Wang, Shixiong
- Subjects
- *
EXTRACTION (Chemistry) , *GOLD compounds , *SOLUTION (Chemistry) , *SULFOXIDE derivatives , *AMINES , *KEROSENE , *NUCLEAR magnetic resonance spectroscopy - Abstract
The synergistic effect of a mixture of bis(2-ethylhexyl) sulfoxide (BESO) and primary amine N1923 in kerosene on the extraction of Au(I) from alkaline cyanide solution was investigated. Experimental results demonstrate that addition of BESO into the organic phase can significantly enhance the basicity of amine N1923, in which the pH 50 value can reach up to 11.91. Slope analysis suggested that the composition of the extracted complexes in the organic phase is [Au(CN) 2 − ·RNH 3 + ·2BESO]. The extracted complexes were characterized by FTIR spectroscopy, 1 H NMR spectroscopy, mass spectrometry, and electrical conductivity analysis. FTIR and 1 H NMR studies reveal strong interactions between BESO and N1923 molecules through hydrogen bonding between the O atoms in the S O groups and the H atoms in the –NH 2 groups, forming S O…H–N. This hydrogen bonding enhances the basicity of N1923 and consequently the ability of N1923 to capture proton; Au(CN) 2 − serves as a counter anion against the protonated amine cation in the organic phase. Electrical conductivity measurements confirmed ionic character of the extracted complexes. The Au(I) extraction in the N1923/BESO system most probably involves the ion-association (ion pair) mechanism. A plausible microstructural model of the extracted complexes was proposed in the paper. Moreover, gold could be efficiently stripped from the loaded organic phase by using sodium hydroxide solution. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
9. Thermodynamic and column studies of Au(I) adsorption on weak alkaline anion exchange fibre from cyanide leaching solution.
- Author
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Li, Mingyu, Zheng, Juan, Zeng, Qingxuan, and Shang, Xiaoqian
- Subjects
- *
METAL absorption & adsorption , *ION exchange resins , *GOLD cyanides , *ELUTION (Chromatography) , *ENDOTHERMIC reactions - Abstract
A novel method of adsorption of Au(I) from cyanide leaching solution with weak alkaline anion exchange fibre (WAAEF) was studied here. The thermodynamics of Au(I) from cyanide leaching solution by the WAAEF from 288 K to 308K have been investigated. Langmuir, Freundlich and Temkin models were adopted and the results confirmed that the Freundlich model fitted best with the equilibrium data. Thermodynamic calculation indicated that the absorption of Au(I) from cyanide leaching solution by WAAEF was an endothermic process with increased entropy. In the dynamic adsorption process, the optimal operational conditions,i.e. flow rate 670.0 BV⋅h−1, loading density 0.211 g⋅cm−3and pH value 8.89 of the original solution, were obtained. Dynamic analytical analysis depicted that the elution yield could exceed up to 97% using a mixture of 3% H2SO4and 8% (NH2)2CS solution at a flow rate of 100.5 BV⋅h−1. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
10. Artificial Protein Cages Assembled via Gold Coordination.
- Author
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Majsterkiewicz K, Stupka I, Borzęcka-Solarz K, Biela A, Gaweł S, Pasternak M, and Heddle J
- Subjects
- Gold, Drug Delivery Systems
- Abstract
Artificial protein cages made from multiple copies of a single protein can be produced such that they only assemble upon addition of a metal ion. Consequently, the ability to remove the metal ion triggers protein-cage disassembly. Controlling assembly and disassembly has many potential uses including cargo loading/unloading and hence drug delivery. TRAP-cage is an example of such a protein cage which assembles due to linear coordination bond formation with Au(I) which acts to bridge constituent proteins. Here we describe the method for production and purification of TRAP-cage., (© 2023. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2023
- Full Text
- View/download PDF
11. Facile morphology control of gold(0) structures from aurophilic assemblies
- Author
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Universitat Politècnica de Catalunya. Departament d'Enginyeria Química, Universitat Politècnica de Catalunya. NEMEN - Nanoenginyeria de materials aplicats a l'energia, Aguiló, Elisabet, Dalmases, Mariona, Lin, Mengxi, Lima, João Carlos, Gavara Castell, Raquel, Figuerola, Albert, Llorca Piqué, Jordi, Rodriguez Raurell, Laura, Universitat Politècnica de Catalunya. Departament d'Enginyeria Química, Universitat Politècnica de Catalunya. NEMEN - Nanoenginyeria de materials aplicats a l'energia, Aguiló, Elisabet, Dalmases, Mariona, Lin, Mengxi, Lima, João Carlos, Gavara Castell, Raquel, Figuerola, Albert, Llorca Piqué, Jordi, and Rodriguez Raurell, Laura
- Abstract
Different gold microstructures have been synthesized by using supramolecular gold(I) organometallic compounds as templates and Ag nanoparticles as reducing agents. The use of fibers resulting from supramolecular assemblies of neutral gold(I) compounds gives rise to the formation of microrods. The use of supramolecular assemblies from ionic molecules results in spherical or square-based prism gold microstructures, depending on the shape of the supramolecular gold(I) precursor assembly. In addition to temperature and reaction time, solvents exert a strong influence on the formation and morphology of gold structures, as borne out by the example that well-defined star-like morphologies have been obtained in chloroform., Peer Reviewed, Postprint (author's final draft)
- Published
- 2020
12. Potential energy surface and molecular dynamics simulation of gold(I) in liquid nitromethane
- Author
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Injan, Natcha, Megyes, Tünde, Radnai, Tamas, Bako, Imre, Balint, Szabolcz, Limtrakul, Jumras, Spangberg, Daniel, and Probst, Michael
- Subjects
- *
POTENTIAL energy surfaces , *GOLD compounds , *NITROMETHANE , *MOLECULAR dynamics , *SOLVATION , *QUANTUM chemistry , *SIMULATION methods & models - Abstract
Abstract: Potential energy functions for Au(I)-nitromethane (NM, CH3NO2) and NM–NM interactions were calculated by fitting analytical expressions to quantum chemically derived energies. These functions were then used in a molecular dynamics simulation of one Au(I) cation in 499 nitromethane molecules in the NVT ensemble at room temperature. A comparative simulation with a generic NM–NM potential energy function was also performed for comparison and gave the same results with respect to the calculated properties. It was found that the first solvation shell around the gold ion contains 9–10 nitromethane molecules in an environment with no strong symmetry. Complementary, cluster calculations on AuNM n + were performed. The especially strong binding of nitromethane in AuNM2 + and the validity of the pair approximation are discussed. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
13. Antileishmanial activity and insights into the mechanisms of action of symmetric Au(I) benzyl and aryl-N-heterocyclic carbenes.
- Author
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Rosa, Letícia B., Galuppo, Carolina, Lima, Rochanna L.A., Fontes, Josielle V., Siqueira, Fábio S., Júdice, Wagner A.S., Abbehausen, Camilla, and Miguel, Danilo C.
- Subjects
- *
CYSTEINE proteinases , *CARBENES , *MEMBRANE permeability (Biology) , *CELL membranes - Abstract
Leishmania amazonensis and L. braziliensis are the main etiological agents of the American Tegumentary Leishmaniasis (ATL). Taking into account the limited effectiveness and high toxicity of the current drug arsenal to treat ATL, novel options are urgently needed. Inspired by the fact that gold-based compounds are promising candidates for antileishmanial drugs, we studied the biological action of a systematic series of six (1)-(6) symmetric Au(I) benzyl and aryl-N-heterocyclic carbenes. All compounds were active at low micromolar concentrations with 50% effective concentrations ranging from 1.57 to 8.30 μM against Leishmania promastigotes. The mesityl derivative (3) proved to be the best candidate from this series, with a selectivity index ~13 against both species. The results suggest an effect of the steric and electronic parameters of the N-substituent in the activity. Intracellular infections were drastically reduced after 24h of (2)-(5) incubation in terms of infection rate and amastigote burden. Further investigations showed that our compounds induced significant parasites' morphological alterations and membrane permeability. Also, (3) and (6) were able to reduce the residual activity of three Leishmania recombinant cysteine proteases, known as possible targets for Au(I) complexes. Our promising results open the possibility of exploring gold complexes as leishmanicidal molecules to be further screened in in vivo models of infection. [Display omitted] • A benzyl and aryl Au(I)-NHC series showed effects of N-substituent in Leishmania. • Au(I)-NHC (3) showed the best leishmanicidal activity. • Morphological changes on promastigotes were detected after Au(I)-NHC incubation. • Leishmania 's plasma membrane and cysteine proteases activity were affected by (3). [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
14. Facile morphology control of gold(0) structures from aurophilic assemblies
- Author
-
Mengxi Lin, Laura Rodríguez, Raquel Gavara, Elisabet Aguiló, João C. Lima, Mariona Dalmases, Albert Figuerola, Jordi Llorca, Universitat Politècnica de Catalunya. Departament d'Enginyeria Química, and Universitat Politècnica de Catalunya. NEMEN - Nanoenginyeria de materials aplicats a l'energia
- Subjects
Morphology (linguistics) ,Materials science ,Porphyrins ,Reducing agent ,Supramolecular assemblies ,Supramolecular chemistry ,Ionic bonding ,macromolecular substances ,Química supramolecular ,Inorganic Chemistry ,Enginyeria química [Àrees temàtiques de la UPC] ,Or -- Microestructura ,Electron microscopy ,Molecule ,Porfirines ,Au(I) ,Ag NPs ,Group 2 organometallic chemistry ,Reduction ,Au microstructures ,technology, industry, and agriculture ,Microstructure ,Template ,Microscòpia electrònica ,Chemical engineering ,Compostos d'or ,lipids (amino acids, peptides, and proteins) ,Gold compounds ,Morphologycontrol - Abstract
Different gold microstructures have been synthesized by using supramolecular gold(I) organometallic compounds as templates and Ag nanoparticles as reducing agents. The use of fibers resulting from supramolecular assemblies of neutral gold(I) compounds gives rise to the formation of microrods. The use of supramolecular assemblies from ionic molecules results in spherical or square-based prism gold microstructures, depending on the shape of the supramolecular gold(I) precursor assembly. In addition to temperature and reaction time, solvents exert a strong influence on the formation and morphology of gold structures, as borne out by the example that well-defined star-like morphologies have been obtained in chloroform.
- Published
- 2020
15. Spectroscopic study of phosphine selenide complexes of Au(I) and X-ray structure of [(cyclohexyl)3PSeAuBr].
- Author
-
Hussain, M. and Isab, A.
- Abstract
The X-ray structure determination of the complex, [(cyclohexyl)
3 PSe-AuBr], revealed a triclinic space group P-1, with a = 9.7654(7), b = 10.9441(9), c = 11.2064(9) Å, α = 117.076(6)°, β = 99.076(6)° γ = 95.417(6)°, V = 1034.07(14) Å3 and Z = 2. The Au(I) atom in this complex has a linear coordination with Se1 atom at 2.3776(9) Å on one side and Br1 at 2.3843(9) Å at the trans position making the Se1-Au1-Br1 angle of 177.97(4)°. The P1 atom in the phosphine has tetrahedral geometry. All three cyclohexyl groups are in their usual boat conformation. The phosphorus atom of the triphenylphosphine is approximately perpendicular to the Se1—Au1—Br1 linkage with P1—Se1—Au1 angle of 99.19(6)°. The Δδ in the31 P NMR of the free ligands and their corresponding L—Se—Au—Br (L—Se = trialkyl/arylphosphine selenides) complexes, and the changes in the P—Se bond frequencies in the FTIR upon complexation, are indicative of the bonding of the ligand to Au(I) through selenium. There is a strong corelation between the chemical shifts of the31 P NMR and the C—P—C angle in the phosphines. [ABSTRACT FROM AUTHOR]- Published
- 2000
- Full Text
- View/download PDF
16. Synthesis, reactivity and cytotoxic properties of water soluble coinage metal N-Heterocyclic Carbene complexes
- Author
-
Bagnarelli L., Santini C., Porchia M., Tisato F., Marzano C., Gandin V., and Pellei M.
- Subjects
Reactivity properties ,Cytotoxic properties ,ynthesis ,Ag(I) ,Cu(I) ,Au(I) - Abstract
Recently we have focused the research work on 11th group metal-NHCs complexes obtained from water soluble 1,3-symmetrically and 1,3-unsymmetrically substituted NHCs precursors based on imidazole and benzoimidazole scaffolds4-6...
- Published
- 2019
17. Au(I) catalyzed synthesis of chiral heterocycles and development of new phosphahelicenes as ligands for enantioselective catalysis
- Author
-
Magné, Valentin, Institut de Chimie des Substances Naturelles (ICSN), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université Paris-Saclay, and Angela Marinetti
- Subjects
[CHIM.ORGA]Chemical Sciences/Organic chemistry ,Enantiosélectivité ,Enantioselectivity ,Spiroindole ,Phosphahélicène ,[CHIM.CATA]Chemical Sciences/Catalysis ,Catalyse ,Au(I) ,Phosphahelicene ,Catalysis - Abstract
Au(I) catalysis is a powerfull tool for heterocycles synthesis, particularly in reactions involving alkynes or allenes. It can be applied both in the synthesis of complex molecules or in the context of total synthesis. During this PhD work, we have developed new chiral Au(I) complexes and new catalytic reactions. We have developed a new family of enantiopure chiral phosphines featuring helicoïdal chirality, obtained by a [2+2+2] cyclotrimerization of alkynes as key step. They have been engaged in late stage functionalization, so as to modify the steric environment and to modify the enantiomeric excess obtained during the catalytic steps. We then studied the phosphine complexation with Au(I) salts. The corresponding phosphahelicenes have been engaged in cycloisomerization reactions. With the best catalyst, a good catalytic activity and an enantiomeric excess of 94 % have been measured. New reactions catalyzed by Au(I) complexes for the synthesis of spiroindolic compounds have been studied, by dearomatizing cyclisation of N-propargyl tryptamines. With this approach, new spirooxindoles and new spiroindolenines have been synthetized. Finally, the enantioselective cycloisomerization of an allenyl pyrrole was studied with chiral Au(I) catalysts. This reaction led to an advanced intermediate, which was converted in few steps to (-)-rhazinilam, a natural product featuring interesting bioactivities. Thus we have described the shortest total synthesis of this natural compound.; La catalyse à l’Au(I) est un outil très puissant pour la synthèse d’hétérocycles, en particulier dans des réactions impliquant des alcynes ou des allènes. Il est notamment possible de l'appliquer dans la synthèse de molécules complexes et dans un contexte de synthèse totale. Au cours de ce travail de thèse, nous avons développé de nouveaux complexes d'Au(I) chiraux, mais également de nouvelles réactions catalytiques. Nous avons développé une nouvelle famille de phosphines chirales énantiopures à chiralité hélicoïdale, obtenues par une étape-clé de cyclotrimérisation [2+2+2] d’alcynes. Elles ont pu être engagées dans des étapes de fonctionnalisations tardives, de manière à modifier l’environnement stérique et de modifier l’excès énantiomérique obtenu lors des étapes catalytiques. Nous avons étudié la complexation des phosphines avec des sels d'Au(I). Les phosphahélicènes obtenus ont ensuite été évalués dans une réaction de cycloisomérisation, et une bonne activité catalytique et un excès énantiomérique atteignant 94 % a été mesuré. De nouvelles réactions de synthèse de dérivés spiroindoliques par catalyse à l’Au(I) ont aussi été mises au point, par le biais de réactions de cyclisation désaromatisante sur des N-propargyl tryptamines. Ainsi, de nouveaux spirooxindoles et de nouvelles spiroindolénines ont été synthétisées. Enfin, une réaction énantiosélective de cycloisomérisation d'un allenyl pyrrole a été mise au point en utilisant des complexes d'Au(I) chiraux. Elle a conduit à un intermédiaire synthétique avancé, qui a été converti en quelques étapes en (-)-rhazinilame, un produit naturel d'intérêt biologique. Ainsi nous avons décrit la plus courte synthèse totale de ce composé.
- Published
- 2017
18. Synthèse d'hétérocycles chiraux par catalyse à l'Au(I) et développement de nouveaux phosphahélicènes pour la catalyse énantiosélective
- Author
-
Magné, Valentin, Institut de Chimie des Substances Naturelles (ICSN), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université Paris-Saclay, and Angela Marinetti
- Subjects
[CHIM.ORGA]Chemical Sciences/Organic chemistry ,Enantiosélectivité ,Enantioselectivity ,Spiroindole ,Phosphahélicène ,[CHIM.CATA]Chemical Sciences/Catalysis ,Catalyse ,Au(I) ,Phosphahelicene ,Catalysis - Abstract
Au(I) catalysis is a powerfull tool for heterocycles synthesis, particularly in reactions involving alkynes or allenes. It can be applied both in the synthesis of complex molecules or in the context of total synthesis. During this PhD work, we have developed new chiral Au(I) complexes and new catalytic reactions. We have developed a new family of enantiopure chiral phosphines featuring helicoïdal chirality, obtained by a [2+2+2] cyclotrimerization of alkynes as key step. They have been engaged in late stage functionalization, so as to modify the steric environment and to modify the enantiomeric excess obtained during the catalytic steps. We then studied the phosphine complexation with Au(I) salts. The corresponding phosphahelicenes have been engaged in cycloisomerization reactions. With the best catalyst, a good catalytic activity and an enantiomeric excess of 94 % have been measured. New reactions catalyzed by Au(I) complexes for the synthesis of spiroindolic compounds have been studied, by dearomatizing cyclisation of N-propargyl tryptamines. With this approach, new spirooxindoles and new spiroindolenines have been synthetized. Finally, the enantioselective cycloisomerization of an allenyl pyrrole was studied with chiral Au(I) catalysts. This reaction led to an advanced intermediate, which was converted in few steps to (-)-rhazinilam, a natural product featuring interesting bioactivities. Thus we have described the shortest total synthesis of this natural compound.; La catalyse à l’Au(I) est un outil très puissant pour la synthèse d’hétérocycles, en particulier dans des réactions impliquant des alcynes ou des allènes. Il est notamment possible de l'appliquer dans la synthèse de molécules complexes et dans un contexte de synthèse totale. Au cours de ce travail de thèse, nous avons développé de nouveaux complexes d'Au(I) chiraux, mais également de nouvelles réactions catalytiques. Nous avons développé une nouvelle famille de phosphines chirales énantiopures à chiralité hélicoïdale, obtenues par une étape-clé de cyclotrimérisation [2+2+2] d’alcynes. Elles ont pu être engagées dans des étapes de fonctionnalisations tardives, de manière à modifier l’environnement stérique et de modifier l’excès énantiomérique obtenu lors des étapes catalytiques. Nous avons étudié la complexation des phosphines avec des sels d'Au(I). Les phosphahélicènes obtenus ont ensuite été évalués dans une réaction de cycloisomérisation, et une bonne activité catalytique et un excès énantiomérique atteignant 94 % a été mesuré. De nouvelles réactions de synthèse de dérivés spiroindoliques par catalyse à l’Au(I) ont aussi été mises au point, par le biais de réactions de cyclisation désaromatisante sur des N-propargyl tryptamines. Ainsi, de nouveaux spirooxindoles et de nouvelles spiroindolénines ont été synthétisées. Enfin, une réaction énantiosélective de cycloisomérisation d'un allenyl pyrrole a été mise au point en utilisant des complexes d'Au(I) chiraux. Elle a conduit à un intermédiaire synthétique avancé, qui a été converti en quelques étapes en (-)-rhazinilame, un produit naturel d'intérêt biologique. Ainsi nous avons décrit la plus courte synthèse totale de ce composé.
- Published
- 2017
19. On the ligand exchange, redox, and disproportionation processes of tetrachloroaurate in the presence of a pyridine derivative.
- Author
-
Simon, Sajna, Clarke, Osai J.R., and Burgess, Ian J.
- Subjects
- *
PYRIDINE derivatives , *OXIDE electrodes , *METALLIC oxides , *GOLD nanoparticles , *OXIDATION-reduction reaction , *SUBSTITUTION reactions , *ELECTROLYTIC corrosion - Abstract
The potential applications of AuI precursors and pyridine derivatives for shape-directed nanoparticle growth has provided an impetus for the present study of the chemistry of tetrachloroaurate (AuCl 4 −) in the presence of 4-methoxypyridine (Py/). Electrochemical experiments show that the addition of Py/ to AuCl 4 − leads to the co-existence of both AuIII and AuI species as evidenced by the observation of two reduction events in the cyclic voltammetry. Kinetic analyses have been used to show that multiple ligand exchange processes occur over the course of several minutes and result in the formation of a AuIII species with two Py/ and a variable number of chloro and hydroxo ligands in the inner sphere. The kinetics of the initial Py/ substitution reaction are shown to follow a modified form of the two-term rate law typical of square planar complexes. The observation of a slow, but spontaneous, conversion of AuIII species to AuI species has been explained by estimating the standard reduction potential for the pyridine/pyridine-N-oxide redox couple and demonstrating that it can drive a galvanic reaction with the AuPy 2 / C l q (OH) 2 − q + / AuPy 2 / + redox couple. The previously reported tendency of this system to form highly anisotropic gold nanoparticles on conductive metal oxide electrodes is explained by a thermodynamic analysis of the disproportionation reaction of AuPy 2 / +. Image, graphical abstract [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
20. STRUCTURAL EFFECTS OF THE AU(I) DRUG AURANOFIN ON CELL MEMBRANES AND MOLECULAR MODELS
- Author
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Mario Suwalsky, Fernando Villena, Silvia Bolognin, and Raquel González
- Subjects
Auranofin ,Red Cell ,Molecular model ,Chemistry ,erythrocyte membrane ,Cell ,General Chemistry ,neuroblastoma cells ,medicine.anatomical_structure ,Membrane ,Gold Compounds ,Biochemistry ,Monolayer ,phospholipid bilayer ,medicine ,Gold ,Viability assay ,Au(I) ,medicine.drug - Abstract
Auranofin is a gold compound that is widely used for the treatment of rheumatoid arthritis. It is a monomeric linear complex with triethylphosphine and thiolate moieties bounded to an Au(I) center. Gold compounds are well known for their neurological and nephrotoxic implications. However, haematological toxicity is one of the most serious toxic and less studied effects. The lack of information on these aspects of auranofin prompted us to study the structural effects induced on cell membranes, particularly that of human erythrocytes. Auranofin was incubated with intact erythrocytes and molecular models of the erythrocyte membrane. The latter consisted of multibilayers of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE), phospholipids classes located in the outer and inner monolayers of the human erythrocyte membrane, respectively. This report presents evidence in order that auranofin interacts with red cell membranes as follows: a) in scanning electron microscopy studies on human erythrocytes it was observed that auranofin induced shape changes; b) X-ray diffraction studies showed that auranofin induced increasing structural perturbation to DMPC and to a lower extent to DMPE bilayers. Additional experiments were performed in human neuroblastoma cells SH-SY5Y. A statistically significant decrease of cell viability was observed.
- Published
- 2013
- Full Text
- View/download PDF
21. Carbenos de Au(I) soportados en redes poliméricas porosas para catálisis
- Author
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Ruiz Echávarri, Adrián, Miguel García, Jesús Ángel, and Universidad de Valladolid. Facultad de Ciencias
- Subjects
Au(I) ,Catálisis heterogénea ,Carbenos ,Polimeros - Abstract
En este TFM, se han funcionalizado una red polimérica porosa (PPN) con carbenos de Au(I), obteniéndose aproximadamente un 60% de grupos funcionales. Para ello, se ha hecho un seguimiento por IR de las distintas etapas de síntesis, previamente probadas y caracterizadas sobre un modelo. El PPN funcionalizado ha catalizado exitosamente la ciclación de eneinos y ha resultado ser más estable frente a la aparición Au(0), apoyando la hipótesis de un posible mecanismo de desproporción., Departamento de Química Física y Química Inorgánica, Máster en Química Sintética e Industrial
- Published
- 2017
22. From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer
- Author
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Jan C. Namyslo, Ming Liu, Mika Polamo, Martin Nieger, Andreas Schmidt, and Department of Chemistry
- Subjects
carbene tautomer ,116 Chemical sciences ,chemistry.chemical_element ,Borane ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Medicinal chemistry ,mesoionic compound ,Full Research Paper ,Rhodium ,Adduct ,PALLADIUM COMPLEXES ,lcsh:QD241-441 ,chemistry.chemical_compound ,ADDUCTS ,lcsh:Organic chemistry ,Triphenylphosphine ,COORDINATION CHEMISTRY ,lcsh:Science ,INTERCONVERSIONS ,PRECURSORS ,AU(I) ,010405 organic chemistry ,CATALYSIS ,Transition metal carbene complex ,Organic Chemistry ,Cationic polymerization ,article ,anionic ligand ,Tautomer ,mesomeric betaine ,0104 chemical sciences ,3. Good health ,Chemistry ,BOND FORMATION ,chemistry ,ddc:540 ,METAL-COMPLEXES ,LIGANDS ,lcsh:Q ,Carbene ,imidazol-2-ylidene - Abstract
The mesomeric betaine imidazolium-1-ylphenolate forms a borane adduct with tris(pentafluorophenyl)borane by coordination with the phenolate oxygen, whereas its NHC tautomer 1-(2-phenol)imidazol-2-ylidene reacts with (triphenylphosphine)gold(I) chloride to give the cationic NHC complex [Au(NHC)2][Cl] by coordination with the carbene carbon atom. The anionic N-heterocyclic carbene 1-(2-phenolate)imidazol-2-ylidene gives the complexes [K][Au(NHC−)2], [Rh(NHC−)3] and [Ni(NHC−)2], respectively. Results of four single crystal analyses are presented.
- Published
- 2016
23. From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer
- Author
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University of Helsinki, Department of Chemistry, Liu, Ming, Namyslo, Jan C., Nieger, Martin, Polamo, Mika, Schmidt, Andreas, University of Helsinki, Department of Chemistry, Liu, Ming, Namyslo, Jan C., Nieger, Martin, Polamo, Mika, and Schmidt, Andreas
- Abstract
The mesomeric betaine imidazolium-1-ylphenolate forms a borane adduct with tris(pentafluorophenyl) borane by coordination with the phenolate oxygen, whereas its NHC tautomer 1-(2-phenol) imidazol-2-ylidene reacts with (triphenylphosphine) gold(I) chloride to give the cationic NHC complex [Au(NHC)(2)][Cl] by coordination with the carbene carbon atom. The anionic N-heterocyclic carbene 1-(2-phenolate) imidazol-2-ylidene gives the complexes [K][Au(NHC-)(2)], [Rh(NHC-)(3)] and [Ni(NHC-)(2)], respectively. Results of four single crystal analyses are presented.
- Published
- 2016
24. Photophysical Property of Catena-Bis(thiocyanato)aurate(I) Complexes in Ionic Liquids
- Author
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Aoyagi, N., Shinha, Y., Ikeda-Ohno, A., Haga, Y., Shimojo, K., Brooks, N. R., Izuoka, A., Naganawa, H., Kimura, T., and Binnemans, K.
- Subjects
ionic liquids ,thiocyanate ,XAS ,TRLFS ,aurophilic interaction ,Gold ,Au(I) ,exciplex ,polymers - Abstract
The photochemistry of a gold(I) thiocyanate complex has been investigated to determine the coordination structure in both the solid and liquid states. The coordination geometries of the supramolecular [Au(SCN)2]n complex and the concomitant exciplex have mainly been analyzed by crystallographic analysis and X-ray absorption spectroscopy. The Au-S bond distance and Au···Au separation of the compound in the S0 ground state and in the T1 phosphorescent excited state (λex = 340 nm) were compared. Upon irradiation with UV light, the excimeric interactions were enhanced, resulting in a contraction of the AuI···AuI aurophilic distance by 0.0113(4) Å. A broad luminescence spectrum was observed for the one-dimensional chain suprastructure. The time-resolved luminescence spectra indicated the entity of several oligomeric species in the crude liquid without neutral solvent molecules. In addition, EXAFS spectroscopy exhibited a slight change in the nearest Au-S distance due to the photo-switched transformation. The deformation of the (Au---Au)* exciplexes was not apparently promoted in the liquid state with the asymmetrical imidazoium cations having a non-local charge distribution in the present observation.
- Published
- 2015
25. Catalyseurs d'oxydation et carbènes hétérocycliques organophosphorés
- Author
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El Kazzi, A., Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Université Paul Sabatier - Toulouse III, Antoine BACEIREDO - Tsuyoshi KATO, Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
catalyse organique ,carbènes ,oxydation ,[CHIM]Chemical Sciences ,Phosphore ,Au(I) - Abstract
In the first part of this study is presented the synthesis of a novel family of phosphorylated catalysts for oxidation that are performing and selective. We develop the synthesis of N-phosphonio imines that allow catalytic epoxidation of olefins. A detailed study shows how the reactivity of the imine function can easily be modulated by variation of the nature of the substituent which helps adapting the catalyst to the type of substrate to oxidize. In the second part, a novel synthesis of precursors of vinylidenephosphoranes carbenes, that is short and simple, is proposed. This synthesis could be applied with different kind of substituent which permits the easy modulation of the properties of this new family of vinylidenephosphorane carbenes. The first results show that these carbenes have a pronounced ambiphilic character with an especially high nucleophilicity as estimated by theoretical study. Tests in coordination chemistry are also presented and the first Au(I) complexe is isolated and characterized by X-ray diffraction study.; Dans la première partie, est présentée la synthèse d'une nouvelle famille de catalyseurs d'oxydation phosphorés performants et sélectifs. Ainsi nous avons mis au point la synthèse des imines N-phosphonio qui permettent de réaliser l'époxydation catalytique des oléfines. Une étude détaillée montre comment on peut facilement moduler la réactivité de la fonction imine en jouant sur la nature des substituants, et ainsi pouvoir adapter le catalyseur au type de substrat à oxyder. Dans la deuxième partie, est décrite une nouvelle voie de synthèse, simple et courte, pour les précurseurs des carbènes vinylidènephosphoranes. Cette voie de synthèse autorise une grande variation dans le choix des substituants ce qui devrait permettre de moduler facilement les propriétés de cette nouvelle famille de carbènes. Les premiers résultats montrent que ces carbènes présentent un caractère ambiphile prononcé avec une nucléophilie exacerbée, comme prévu par des calculs théoriques. Les premiers résultats en chimie de coordination sont également présentés et le premier complexe de Au(I) a été isolé et caractérisé par diffraction des rayons X.
- Published
- 2008
26. Excellent correlation between cathepsin B inhibition and cytotoxicity for a series of palladacycles
- Author
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Olivier Zava, Paul J. Dyson, Michael B. Hursthouse, Angela Casini, Rajendra P. Rathnam, John Spencer, Michel Pfeffer, Samantha K. Callear, and Santosh K. Velhanda
- Subjects
Metallocenes ,Phosphines ,Stereochemistry ,Adamantane ,Molecular Conformation ,chemistry.chemical_element ,Crystallography, X-Ray ,Cathepsin B ,Inorganic Chemistry ,chemistry.chemical_compound ,Organophosphorus Compounds ,Complexes ,Coordination Complexes ,Cell Line, Tumor ,Humans ,Lysosomal Cysteine Proteases ,Ferrous Compounds ,Breast-Cancer ,Au(I) ,chemistry.chemical_classification ,Progression ,Bioorganometallic chemistry ,Drugs ,Nuclear magnetic resonance spectroscopy ,Monomer ,Enzyme ,chemistry ,Ferrocene ,Bioorganometallic Chemistry ,Pharmaceuticals ,Palladium - Abstract
The reaction of the five- or six-membered C,N or C,S-palladacycles [(L)PdCl](2) with PTA (1,3,5-triaza-7-phosphaadamantane) led to the monomeric complexes [(L)Pd(PTA)Cl] 6a, 6b and 7 where LH= N,N-dimethyl-1-phenylmethanamine, benzyl(methyl)sulfane or 1-methyl-5-phenyl-1H-benzo[e][1,4]diazepin-2(3H)-one respectively. Dimeric complexes have also been synthesised: [Pd(2)L(2)(mu-dppe)Cl(2)], where LH = 1-methyl-5-phenyl-1H-benzo[e][1,4]diazepin-2(3H)-one (1a), (R)- or (S)-3-isopropyl-1-methyl-5-phenyl-1H-benzo[e][1,4]diazepin-2(3H)-one (1b, 1c), [Pd(2)L(2)(mu-dppf)Cl(2)], where L= 1-methyl-5-phenyl-1H-benzo[e][1,4]diazepin-2(3H)-one (4a) or (R)-3-isopropyl-1-methyl-5-phenyl-1H-benzo[e][1,4]diazepin-2(3H)-one (4b), respectively, and dppe = 1,2-bis(diphenylphosphino)ethane, dppf = 1,1'-bis(diphenylphosphino)ferrocene. The complexes were characterised in solution, by (1)H and (31)P NMR spectroscopy, and single crystals of complexes 6b and 7 were studied in the solid state by X-ray crystallography. The palladacycles were evaluated for in vitro activity as cytotoxic agents on A2780/S cells and also as cathepsin B inhibitors, an enzyme implicated in a number of cancer related events.
- Published
- 2009
- Full Text
- View/download PDF
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