- Consecutive Nucleation and Confinement Modulation towards Li Plating in Seeded Capsules for Durable Li-Metal Batteries
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A dual modulation strategy of consecutive nucleation and confined growth of Li metal is proposed by using the metal–organic framework (MOF) derivative hollow capsule with inbuilt lithiophilic Au or Co-O nanoparticle (NP) seeds as heterogeneous host. The seeding-induced nucleation enables the negligible overpotential and promotes the inward injection of Li mass into the abundant cavities in host, followed by the conformal plating of Li on the outer surface of host during discharging. This modulation alleviates the dendrite growth and volume expansion of Li plating. The interconnected porous host network enables enhancement of cycling and rate performances of Li metal (a lifespan over 1200 h for Au-seeding symmetric cells, and an endurance of 220 cycles under an ultrahigh current density of 10 mA cm?2 for corresponding asymmetric cells). The hollow capsules integrated with lithiophilic seeds solve the deformation problem of Li metal for durable and long-life Li-metal batteries.
- Huang, Minsong,Yao, Zhenguo,Yang, Qifan,Li, Chilin
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supporting information
p. 14040 - 14050
(2021/05/13)
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- DOUBLE GOLD(III)–ZINC(II) DI-ISO-BUTYLDITHIOCARBAMATO- CHLORIDO COMPLEXES OF THE COMPOSITION [Au(S2CNR2)2]2[Zn2Cl6] AND [Au(S2CNR2)2][Zn(S2CNR2)Cl2]: SYNTHESIS, STRUCTURAL ORGANIZATION, 13C CP-MAS NMR, AND THERMAL BEHAVIOR
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Abstract: The interaction of zinc(II) di-iso-butyldithiocarbamate with [AuCl4]— anions in 2M HCl is studied. The result of chemisorption binding of gold(III) from a solution to the solid phase is the formation of double ionic complexes of the compositions [Au{S2CN(iso-C4H9)2}2]2[Zn2Cl6] (1) and [Au{S2CN(iso-C4H9)2}2][Zn{S2CN(iso-C4H9)2}Cl2] (2). The chemical identification of preparatively isolated crystalline compounds was performed by 13C CP-MAS NMR spectroscopy. According to single crystal X-ray diffraction data, structural units of complex 1 are a binuclear zinc anion and non-equivalent complex [Au{S2CN(iso-C4H9)2}2]+ cations: centrosymmetric A with the Au(1) atom and С – Au(3) and non-centrosymmetric В – Au(2). With the participation of secondary Cl?S bonds (3.2407?? and 3.2756??), В cations and anions form supramolecular ionic pairs. The structure of 2 in turn involves the centrosymmetric gold(III) cation whose counterion is a mixed-ligand dithiocarbamato-chlorido anion of zinc(II). Pairs of non-equivalent secondary Cl?S bonds (3.2337?? and 3.3151??) combine the ionic structural units of 2 into zigzag-like pseudo-polymeric chains along which the alternation of complex cations and anions is noted. Thermolysis of complexes in cationic and anionic parts is accompanied by the quantitative regeneration of bound gold along with the formation of ZnCl2 and ZnS.
- Rodina,Loseva,Ivanov
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p. 123 - 136
(2021/02/26)
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- Silver(I) and gold(I) complexes with sulfasalazine: Spectroscopic characterization, theoretical studies and antiproliferative activities over Gram-positive and Gram-negative bacterial strains
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The emergence of bacterial strains resistant to antibiotics, such as the sulfonamides (sulfa drugs), is currently a case of concern. The synthesis of metal complexes using well-known antibacterial agents and bioactive metals has proven to be an excellent strategy in the development of new and more active metallodrugs. Herein, we report the synthesis, structural characterization and antibacterial analysis of new gold(I) and silver(I) complexes with the sulfa drug sulfasalazine (ssz). Elemental, thermal and high-resolution mass spectrometric measurements indicated a 1:1:1 Au/ssz/Ph3P molar composition for the gold(I) complex (Ph3P - triphenylphosphine), while for the silver(I) complex the molar composition was 1:1 Ag/ssz. Solution state NMR and infrared spectroscopic data suggest that ssz coordinates to silver(I) and gold(I) by the oxygen atoms of the deprotonated carboxylic group. The coordination mode of the carboxylate was supported by density functional theory (DFT) calculations, which reinforces a monodentate coordination for the gold(I) complex and a bridged bidentate mode for the silver(I) one, with the molecular formulas [(Ph3P)Au(ssz)] and [Ag(ssz)]2, respectively. Antibacterial activity assays indicated the sensitivity of Gram-positive (Staphylococcus aureus and Bacillus cereus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacterial strains to [Ag(ssz)]2 and [(Ph3P)Au(ssz)] complexes, while the free ligand was not able to inhibit the growth of any tested bacteria. The non-interaction of the complexes with deoxyribonucleic acid (DNA) was also demonstrated, which suggests that this biomolecule is not a preferential target for the compounds.
- Corbi, Pedro P.,Fiori-Duarte, Ana Thereza,Lustri, Wilton R.,Manzano, Carlos M.,de Paiva, Raphael Enoque F.
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- Pharmacological properties of dicyanidoaurate(I)-based complexes: characterization and single crystal X-ray analysis
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Absract: The synthesis of three bimetallic cyanido complexes with edbea [2,2′-(ethylenedioxy)bis(ethylamine)] ligand is reported. [NiII(μ-edbea)2{Au(μ-CN)2}2]n (1), [{CuII(edbea)}2{Au(μ-CN)2}4]n (2) and [CdII(edbea)2][Au(CN)2]2·H2O (3) were fully characterized by elemental, infrared, XRD (3), ESI-MS and thermal analysis. The DNA/BSA binding properties of these complexes were evaluated by spectrophotometric titration, fluorometric ethidium bromide kinetics, and DNA electrophoresis studies and their partially minor groove binding mode between the base pairs of DNA and electrostatic interaction between the amino acid residues of BSA were explained. The complexes were tested for their pharmacological properties. These molecules had excellent in vitro antiproliferative activity and also exhibited a strong tumor inhibiting effect against HT29, HeLa, C6 and Vero cell lines. These complexes had metastatic features as they are able to reduce cell migration activity and suppress tumor growth in vitro. Analysis of the DNA topoisomerase I relaxing activity indicates that the complexes do not inhibit topoisomerase I which regulates the topological states of the DNA double helix during DNA processing reactions. The TUNEL and DNA laddering assay results indicated that these compounds may destroy cell maintenance by triggering apoptosis. Immunohistochemistry staining analysis demonstrated that these complexes significantly decreased the expression of Bcl-2 in HeLa and HT29 cells while increasing the expression of P53 levels. Overall, the potent antiproliferative activity, low cytotoxic effect, good solubility, and micro molar range dosage observed for these complexes emphasizes their potential as anticancer drug candidates.
- Karada?, Ahmet,Aydin, Ali,Tekin, ?aban,Akba?, Hüseyin,Dede, Süreyya
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p. 860 - 878
(2019/03/11)
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- Binding of Gold(III) from Solutions with Thallium(I) Dibutyldithiocarbamate: Synthesis, Supramolecular Self-Organization, and Thermal Behavior of the Complex ([Au{S2CN(C4H9)2}2][TlCl4])n
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The binding of gold(III) from solution in a 2 M HCl with thallium(I) dibutyl dithiocarbamate leads to the formation of ion-polymeric complex ([Au{S2CN(C4H9)2}2][TlCl4])n, which was studied by (13С, 15N) MAS NMR spectroscopy and X-ray diffraction analysis. In the complex comprising the nonequivalent cations [Au{S2CN(C4H9)2}2]+ (A and B) and anions [TlCl4]–, the supramolecular self-assembly is provided by secondary bonds Au···S and S···Cl. The former are involved in the formation of isomeric binuclear cations [А···А] and [В···В] that build the (···[А···А]···[В···В]···)n polymeric chain; the latter selectively combine the thallium(III) anions and the dimeric cations. Thermolysis of the complex is accompanied by gold recovery and release of TlCl.
- Ivanov,Bredyuk,Loseva
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p. 1470 - 1477
(2018/09/11)
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- Strong chiroptical activity from achiral gold nanorods assembled with proteins
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The side-by-side assembly of gold nanorods and proteins, particularly human serum albumin, exhibits a distinct chiroptical activity in a wide range of visible and near-infrared wavelengths corresponding to the surface plasmon resonance. The anisotropy factor was the highest in a colloidal solution system and was able to be inverted by an external environment.
- Shinmori, Hideyuki,Mochizuki, Chihiro
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supporting information
p. 6569 - 6572
(2017/07/10)
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- Large Cu i 8 chalcogenone cubic cages with non-interacting counter ions
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Two mega size copper(i) cubic cages, [{Cu(Bptp)1.5}8(PF6-)](PF6-)7 (1) and [{Cu(Bpsp)1.5}8(PF6-)](PF6-)7 (2), supported by imidazole-2-chalcogenone ligands (Bptp = 2,6-bis(1-isopropylimidazole-2-thione)pyridine and Bpsp = 2,6-bis(1-isopropylimidazole-2-selone)pyridine) have been synthesized and characterized. The formation of ionic salts 1 and 2 was confirmed by FT-IR, multinuclear (1H, 13C, 31P and 19F) NMR, UV-vis, TGA, CHN analysis, BET analysis, single crystal X-ray diffraction and powder X-ray diffraction techniques. To the best of our knowledge, these are the first examples of a octanuclear copper(i) cluster in a perfect cubic architecture with a copper-copper distance of 8.413 ? or 8.593 ?. Interestingly, these anion-centered CuI8 cubic arrangements are not supported by cubic centered ions or face centered molecules. The formation of cationic cubic cages was accompanied by the association of twelve ligands (Bptp or Bpsp) with eight trigonal planar [CuSe3] vertices. The cationic charge of cubic cages was satisfied by eight PF6- counter anions, in which one of the PF6- anions occupies the centre of the Cu8 cube without any interaction. The copper(i) cubic cages are found to be highly active catalysts in click chemistry as well as hydroamination reactions. The scope of the catalytic reactions has been investigated with thirty-five different combinations of click reactions and six different combinations of the hydroamination of alkynes.
- Katam, Srinivas,Ganesan, Prabusankar
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p. 16615 - 16622
(2017/12/15)
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- Double complex salts [Au(En)2][Ir(NO2)6] ? nH2O (n = 0, 2), [Au(En)2][Ir(NO2)6]x[Rh(NO2)6]1–x ? nH2O (x = 0.25, 0.5, 0.75):
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The double complex salts [Au(En)2][Ir(NO2)6] ? 2H2O (I) and [Au(En)2][Ir(NO2)6] (II) and solid solutions [Au(En)2][Ir(NO2)6]x[Rh(NOsu
- Makotchenko,Plyusnin,Shubin, Yu. V.,Baidina,Korol’kov,Sheludyakova,Korenev
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- A new polymorphic modification and chemisorption activity of mercury(II) N,N-di-iso-propyldithiocarbamate: Synthesis and characterisation of the heteronuclear double complex of ([Au{S2CN(iso-C3H7)2}2]2[Hg2Cl6]·OC(CH3)2)n
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A new crystalline modification (γ-form, 1) of the mercury(II) N,N-di-iso-propyldithiocarbamate (Hg-iso-PDtc) has been identified and structurally characterised using single-crystal X-ray diffraction analysis. The crystal structure of 1 is presented by centrosymmetric binuclear molecules of [Hg2{S2CN(iso-C3H7)2}4], in which the mercury atoms are interconnected by two tridentate bridging iso-PDtc ligands. The chemisorption activity of the freshly precipitated Hg-iso-PDtc was tested with respect to gold(III) in a 2?M HCl solution. The novel heteronuclear gold(III)–mercury(II) double complex was found to be the sole gold-containing product of the chemisorption. The isolated compound was crystallised as a solvated form, ([Au{S2CN(iso-C3H7)2}2]2[Hg2Cl6]·OC(CH3)2)n (2). It was revealed that compound 2 adopts a polymeric structure comprising two types (‘A’ and ‘B’) of isomeric gold(III) cations [Au{S2CN(iso-C3H7)2}2]+ and centrosymmetric binuclear mercury(II) anions [Hg2Cl6]2–. The supramolecular self-organisation of 2 occurs due to the relatively weak Au···S secondary interactions between neighbouring isomeric [Au{S2CN(iso-C3H7)2}2]+ cations resulting in the formation of linear cation-cationic chains of (?‘A’?‘B’?‘A’?‘B’?)n. The thermal behaviour of polycrystalline samples of Hg-iso-PDtc and 2 was studied by simultaneous thermal analysis (STA). It was shown that thermal decomposition is accompanied by the formation of HgS (for the original mercury(II) complex) or quantitative reduction of gold(III) to elemental gold and formation of HgCl2 along with its partial transformation to HgS (for 2).
- Loseva, Olga V.,Rodina, Tatyana A.,Smolentsev, Anton I.,Ivanov, Alexander V.
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p. 238 - 245
(2017/07/10)
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- Electron-density distribution tuning for enhanced thermal stability of luminescent gold complexes
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Structure-property relationships of newly synthesized luminescent gold complexes were examined from the viewpoint of material applications. In particular, we investigated the effect of controlling the molecular electron-density distribution by introducing trifluoromethyl substituents into the complexes. The structures of the molecular aggregates were not affected by the trifluoromethyl substituents, as all the complexes formed antiparallel dimers in the crystal state. Moreover, we found that the trifluoromethyl substituents enhanced the thermal stability of the complexes without significantly changing the luminescence behaviour. Thus, while the thermal stability of these materials depends on the molecular structure, i.e. the molecular electron-density distribution, the luminescence behaviour mainly depends on the molecular aggregate structure. These results suggest that various material properties, e.g. luminescence colour and thermal stability, can be controlled independently by tuning the structures of molecules and molecular aggregates using trifluoromethyl substituents.
- Yamada, Shigeyuki,Yamaguchi, Shun,Tsutsumi, Osamu
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p. 7977 - 7984
(2017/08/17)
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- Multiple isomerization of structural units in ion-polymeric heteronuclear gold(III)–zinc(II) complex ([Au{S2CN(C4H9)2}2]2[ZnCl4])n: Chemisorption-based synthesis, supramolecular structure (self-organization of long-period cation–cationic polymer chains), and thermal behavior
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Chemisorption of gold(III) from solutions in 2 M HCl with freshly precipitated binuclear zinc dithiocarbamate [Zn2{S2CN(C4H9)2}4] resulted in the formation of a polymeric heteronuclear gold(III)–zinc(II) dithiocarbamato-chlorido complex ([Au{S2CN(C4H9)2}2]2[ZnCl4])n (I), which was characterized by MAS 13C NMR, X-ray diffraction (CIF file CCDC no. 1526616), and simultaneous thermal analysis. Compound I isolated on a preparative scale was found to have a highly intricate supramolecular structure composed of 13 centrosymmetric and non-centrosymmetric isomeric complex cations, [Au{S2CN(C4H9)2}2]+, with 24 structurally non-equivalent BuDtc ligands, and six isomeric [ZnCl4]2– anions. The isomeric gold(III) cations perform different structural functions. Four and six cations are involved in the formation of two sorts of long-period cation–cationic chains (via pair non-valence secondary AuS bonds): (ABCDCB)n and (FGHIJK)n. The discrete E, L, and M cations and the [ZnCl4]2– complex anions are located alongside of the polymer chains and do not take part in the secondary interactions. According to simultaneous thermal analysis, thermolysis of I includes destruction of the dithiocarbamate moiety with reduction of gold to the metal in the cation and liberation of zinc chloride with partial conversion to ZnS in the anion.
- Ivanov,Loseva,Rodina,Smolentsev
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p. 512 - 525
(2017/08/29)
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- Gold and palladium oxidation/complexation in water by a thioamide-iodine leaching system
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This paper concerns the oxidative dissolution ability of a thioamide/iodine leaching system in water towards gold, palladium and silver metals in powder in view of a potential application in the recovery process of these metals from electrical and electronic waste equipment (E-waste). The leaching mixture composed of equimolar amounts of thioamide 3-methyl-benzothiazole-2-thione and I2 in water can oxidize/complex gold and palladium metals in powder in order to form the complexes [AuI(mbtt)2]I3 and [PdII(mbtt)3I]I3. Considering the mild conditions under which the processes were performed ([I2] = 1.14 × 10-3 M, T = 20 °C, pH = 5.0, leaching time = 24 h), the obtained oxidation yield of Au0 and Pd0 are to be considered satisfactory with values of 65% and 69%, respectively. No oxidation was observed for the silver powder. The oxidising/complexing properties of the leaching mixture mbtt + I2 were interpreted considering the formation of the mbtt-I2 adduct that features, as a consequence of the S-donor to I2 interaction, a charge separation between the bridging and terminal iodine atoms in the fragment S-Ib-It. The feasibility of recovering gold from the complex [AuI(mbtt)2]I3 was verified by performing a cementation with magnesium powder.
- Isaia, Francesco,Aragoni, Maria Carla,Arca, Massimiliano,Caltagirone, Claudia,Castellano, Carlo,De Filippo, Greta,Garau, Alessandra,Lippolis, Vito,Pivetta, Tiziana
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p. 4591 - 4599
(2017/10/13)
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- Construction of polydopamine-coated gold nanostars for CT imaging and enhanced photothermal therapy of tumors: An innovative theranostic strategy
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The advancement of biocompatible nanoplatforms with dual functionalities of diagnosis and therapeutics has been strongly demanded in biomedicine in recent years. In this work, we report the synthesis and characterization of polydopamine (pD)-coated gold nanostars (Au NSs) for computed tomography (CT) imaging and enhanced photothermal therapy (PTT) of tumors. Au NSs were firstly formed via a seed-mediated growth method and then stabilized with thiolated polyethyleneimine (PEI-SH), followed by deposition of pD on their surface. The formed pD-coated Au NSs (Au-PEI@pD NSs) were well characterized. We show that the Au-PEI@pD NSs are able to convert the absorbed near-infrared laser light into heat, and have strong X-ray attenuation properties. Due to the co-existence of Au NSs and pD, the light to heat conversion efficiency of the NSs can be significantly enhanced. These very interesting properties allow them to be used as a powerful theranostic nanoplatform for efficient CT imaging and enhanced phtotothermal therapy of cancer cells in vitro and the xenografted tumor model in vivo. Due to their easy functionalization nature enabled by the coated pD shell, the developed pD-coated Au NSs may be used as a versatile nanoplatform for targeted CT imaging and PTT of different types of cancers.
- Li, Du,Zhang, Yongxing,Wen, Shihui,Song, Yang,Tang, Yueqin,Zhu, Xiaoyue,Shen, Mingwu,Mignani, Serge,Majoral, Jean-Pierre,Zhao, Qinghua,Shi, Xiangyang
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p. 4216 - 4226
(2016/07/06)
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- Synthesis and Properties of Hydrazino Amino Acyclic Carbenes of Gold(I), Platinum(II), Palladium(II) and Rhodium(III)
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The nucleophilic addition of protected and substituted hydrazine derivatives to isonitrile complexes of gold(I), platinum(II), palladium(II) and rhodium(III) provides the corresponding hydrazino amino acyclic carbene complexes. These are characterized by
- T?upova, Svetlana,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
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p. 3999 - 4005
(2016/12/30)
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- Formation of alloys upon the simultaneous electrochemical deposition of gold and tin from ethylene glycol and aqueous electrolytes
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An ethylene glycol (EG) solution containing Au(III) and Sn(IV) compounds, and conditions for the electrochemical deposition of Au–Sn alloy based on AuSn and Au5Sn intermetallics with total tin content of 30–55 at % are proposed. Fundamental difficulties of the deposition of alloys with high tin content, (including eutectic Au–Sn alloy) from aqueous electrolytes are revealed. It is determined via voltammetry that the simultaneous deposition of gold and tin from aqueous and EG electrolytes proceeds with the depolarization effect of both Au(III) and Sn(IV) as a result of the formation of the alloy, the increase in the rate of tin cathodic reduction being more noticeable in case of EG solution. Formation of SnCl2EG(H2O)2 + complex upon the dissolution of SnCl4 · 5H2O in glycol, the stability of the composition of tetracyanoaurate ions upon the dissolution of K[Au(CN)4], and the weakening of intermolecular interactions in EG with small amounts of water were revealed via IR spectroscopy. It is suggested that the depolarization effect is due not only to alloy formation, but also to the formation of SnCl2EG(H2O)2 + cations, their association with Au(CN)4 - anions, and a change in the mechanism of Au(III) and Sn(IV) reduction.
- Vorobyova,Maltanova,Vrublevskaya
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p. 1081 - 1087
(2016/06/09)
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- Synthesis, spectroscopic, and antimicrobial study of Ca(II), Fe(III), Pd(II), and Au(III) complexes of amoxicillin antibiotic drug
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Synthesis, spectroscopic characterization, theoretical and antimicrobial studies of Ca(II), Fe(III), Pd(II), and Au(III) complexes of amoxicillin (amox) antibiotic drug are presented in the current paper. Structure of 1: 1 (metal: amox) complexes were elucidated on the basis of elemental analyses, and IR, Raman, 1H NMR, and electronic spectral data. According to molar conductance measurements the complexes had electrolyte nature. Amoxicillin reacted with metal ions as a tridentate ligand coordinated with metal ions via–NH2,–NH, and β-lactam carbonyl groups. The complexes were formulated as [Ca(amox-Na)(H2O)]·Cl2·4H2O (1), [Fe(amox-Na)(H2O)3]·Cl3·3H2O (2), [Pd(amox-Na)(H2O)]·Cl2 (3), and [Au(amox-Na)(H2O)]·Cl3 (4). Kinetic thermodynamic parameters (E*, ΔS*, ΔH*, and ΔG*) were calculated based on the Coats–Redfern and Horowitz–Metzger methods using thermo gravimetric curves of TG and DTG. Nanosize particles of amoxicillin complexes have been studied by XRD, SEM, and TEM methods. Theoretical studies of the synthesized complexes have been performed.
- Al-Khodir,Refat
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p. 708 - 717
(2016/06/01)
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- Gold(III)-iron(III) heteropolynuclear complexes ([Au{S2CNR2}2][FeCl4]) n (R = C4H9, iso-C4H9): Chemisorption synthesis, supramolecular self-organization, and thermal behavior
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The reactions of iron(III) dibutyl and di-iso-butyl dithiocarbamates [Fe(S2CNR2)3] (R = C4H9, iso-C4H9) with anions [AuCl4]- in 2 M HCl are studied. The result of heterogeneous reactions of gold(III) chemisorption binding from a solution is the formation of gold(III)-iron(III) heteropolynuclear complexes of the ionic type. The crystal and supramolecular structures of polymer complexes ([Au{S2CN(C4H9)2}2][FeCl4]) n (I) and ([Au{S2CN(iso-C4H9)2}2][FeCl4]) n (II) are determined by X-ray diffraction analysis (CIF files CCDC 1407704 (I) and 1407802 (II)). The structure of complex I contains two centrosymmetrical structurally nonequivalent complex cations [AuS{2CN(C4H9)2}2]+ (A and B) and complex anion [FeCl4]-. Structure II is formed by three isomeric complex cations [Au{S2CN(iso-C4H9)2}2]+ (A, B, and C) and two anions [FeCl4]- related as conformers. The isomeric cations are involved in the formation of linear (?A?B?) n (in I) or zigzag (?A?B?A...C...) n (in II) polymer chains due to pairs of weak secondary interactions Au?S. The thermal behavior of the complexes is studied by simultaneous thermal analysis. Thermal destruction includes the thermolysis of the dithiocarbamate moiety of the complexes and anions [FeCl4]- with the reduction of gold(III), release of FeCl3, and partial formation of Fe2O3. The final thermolysis products are metallic gold and Fe2O3.
- Ivanov,Loseva,Rodina,Gerasimenko,Novikova
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p. 104 - 115
(2016/04/05)
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- COLLOIDAL METAL COMPOSITIONS AND METHODS
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The present invention comprises compositions and methods for delivery systems of agents, including therapeutic compounds, pharmaceutical agents, drugs, detection agents, nucleic acid sequences and biological factors. In general, these vector compositions comprise a colloidal metal, derivatized PEG (polyethylene glycol) and an agent. The invention also comprises methods and compositions for making such colloidal metal compositions and for treatment of cancer.
- -
-
Paragraph 0095-0096
(2017/01/09)
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- One-pot synthesis affords perfectly six-fold symmetrical Au microsnowflakes for excellent electrochemical biosensing and surface-enhanced Raman scattering assays
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Herein, Au microsnowflakes with six-fold symmetrical branches were successfully synthesized. The morphological evolution and kinetics mechanism of this microstructure were well explained. By using this micromaterial, the fabricated biosensor shows excellent electrochemical performance in the range of 1 nM to 1 mM with a low detection limit of 352 pM toward adenosine. It also provides excellent selectivity against other deoxyribonucleosides. Meanwhile, the Au microsnowflakes show good performance in surface enhanced Raman scattering for the detection of p-mercapto benzoic acid (PMBA) molecules. This journal is
- Zhang, Yan,Yue, Yonghai,Peng, Yi,Huang, Chengcheng,Li, Lidong,Guo, Lin,Yang, Shihe
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p. 16074 - 16081
(2015/03/04)
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- Methyl ester synthesis catalyzed by nanoporous gold: from 10-9 Torr to 1 atm
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The oxidative coupling reaction of aldehydes with methanol occurs in the vapor phase over a support-free nanoporous gold (npAu) catalyst over a wide pressure range - from 10-9 Torr to 1 atm. The dependence of the aldehyde-to-ester reaction rate on the oxygen, methanol and aldehyde partial pressures suggests that the rate-limiting step for coupling is the reaction of the aldehyde with surface sites saturated with adsorbed methoxy. Stable catalyst activity is achieved for aldehyde-methanol coupling in flowing reactant mixtures at 70 °C. While the conditioned npAu catalyst exhibits high selectivity for methanol-aldehyde coupling, its activity for the self-coupling reaction of methanol to methyl formate is reduced by the exposure to the alcohol-aldehyde mixture in a manner that is consistent with the buildup of spectator species. The activity for methanol self-coupling can be regenerated by extended exposure to flowing methanol, CO and O2 at 70 °C. Overall, the observed catalytic esterification is consistent with model studies of both the npAu catalyst and single crystal gold in ultrahigh vacuum.
- Wang, Lu-Cun,Stowers, Kara J.,Zugic, Branko,Biener, Monika M.,Biener, Juergen,Friend, Cynthia M.,Madix, Robert J.
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p. 1299 - 1306
(2015/02/19)
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- Unexpected synthesis of an Au2In2 tetrametallatricyclic complex from α-aminophosphines and formation of Au-In-P and Ag-In-P nanomaterials
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Four Au-(μ-phosphinite)-In units assemble to form an unprecedented Au2In2 12-membered metallacycle which intersects at the In centres an 8-membered ring containing two In-μ-phosphinate linkages, resulting in a tricyclic structure. Thermal treatment of this complex and of its Ag(i) analog affords Au-In-P and Ag-In-P nanomaterials, respectively.
- Chen, Hsiao Wei,Andy Hor,Pattacini, Roberto,Braunstein, Pierre
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p. 16242 - 16246
(2015/09/28)
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- Two new coordination polymers containing dicyanidoargentate(I) and dicyanidoaurate(I): Synthesis and characterization, and a detailed in vitro investigation of their anticancer activities on some cancer cell lines
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Two novel cyanido-bridged bimetallic polymeric complexes, [Ni(edbea)Ag3 (CN)5 ]n (C1) and [Ni(bishydeten) Au2 (CN)4]n (C2), where edbea = [2,2′-(ethylenedioxy)bis(ethylamine)] and bishydeten = [(N ,N′-bis(2-hydroxyethyl) ethylenediamine)] are ligands, were synthesized and characterized by elemental, infrared, and thermal measurement techniques and investigated for their biological activity in cultured cancer cell lines. The results show that both compounds and free anions, [Ag(CN)2]- and [Au(CN)2]- , exhibited very high antiproliferative activity compared to the anticancer drug 5FU against the cancer cell lines tested. The antiproliferative and cytotoxic activities of C1 and C2 were significantly lower than those of free anions, indicating that the extreme cytotoxicity of free anions decreased to safe levels in C1 and C2. In conclusion, the results show that these novel compounds possess anticancer activities.
- Aydin, Ali,Karada, Ahmet,Tekin, aban,Korkmaz, Nesrin,?zdemir, Aslihan
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p. 532 - 549
(2015/08/06)
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- Unusual electrochemical behaviour of AuBr4- in ionic liquids. Towards a simple recovery of gold(iii) after extraction into an ionic liquid
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The electrochemistry of AuBr4- complexes extracted into ionic liquids [C8PYR][NTf2] or [C8MIM][NTf2] saturated with water and gas has been studied by cyclic voltammetry on a glassy carbon macro electrode and by linear voltammetry on a platinum microelectrode. Unlike AuCl4-, the reduction of AuBr4- to Au(0) is achieved following a one reduction step involving three electrons. The deposition of Au(0) from AuBr4- is carried out at a potential above that of water, leading to the simple and easy deposition of gold and subsequently to the extraction of AuBr4- into an ionic liquid.
- Papaiconomou, Nicolas,Glandut, Nicolas,Billard, Isabelle,Chainet, Eric
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p. 58910 - 58915
(2015/02/19)
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- Synthesis, characterization, molecular modelling and biological activity of 2-(pyridin-1-ium-1-yl) acetate and its Cu2+, Pt4+, Pd2+, Au3+ and Nd3+ complexes
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A new series of Cu2+, Pt4+, Pd2+, Au 3+ and Nd3+ complexes derived from 2-(pyridin-1-ium-1-yl) acetate have been synthesized and characterized using elemental analyses, spectral (infrared (IR), UV-visible, mass, 13C NMR and 1H NMR), magnetic and thermal measurements. IR results suggest that the ligand acts in a neutral monodentate fashion in all complexes. Octahedral geometry is proposed for Cu2+ and Pt4+ complexes and square-planar for Pd2+ and Au3+ complexes. The bond lengths, bond angles, and HOMO and LUMO were calculated. Superoxide dismutase-like radical scavenger activity and cytotoxic activity of the isolated complexes on HepG2 liver cancer cells have been screened. Ligand and complexes (Pt4+ and Nd 3+) exhibit potent antioxidant activity upon coordination while Cu2+ and Au3+ complexes do not show superoxide dismutase-like radical scavenger activity. The cytotoxic activity assay against HepG2 cell line proves that the ligand and its Pt4+ complex have a high cytotoxic activity, while the other complexes showed no cytotoxic activity. Copyright
- Mlahi, Mosaad R.,Negm, Amr,Azhari, Shaker J.,Mostafa, Mohsen M.
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p. 712 - 719
(2014/11/08)
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- Synthesis of Au@Ag@Cu trimetallic nanocrystals using three-step reduction
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Au@Ag@Cu trimetallic nanocrystals were prepared using a three-step reduction method. In the first step, decahedral Au core seeds were prepared by reducing HAuCl4·4H2O in diethylene glycol (DEG) under oil-bath heating in the presence of polyvinylpyrrolidone (PVP) as a polymer surfactant. In the second step, Ag shells were overgrown on these Au seeds in N,N-dimethylformamide (DMF) in the presence of PVP under oil-bath heating to prepare decahedral Au@Ag nanocrystals. In the third step, Cu shells were overgrown further on Au@Ag core-shell nanocrystals in ethylene glycol (EG) in the presence of PVP under oil-bath heating. The resultant crystal shapes were characterized using transmission electron microscopic (TEM), TEM-energy dispersed X-ray spectroscopic (EDS), and X-ray diffraction (XRD) measurements. Results show that Cu shells of two kinds are grown over Au@Ag core seeds: a phase-separated major Cu component attached to one or two side edges of decahedral Au@Ag cores, and a minor Cu component that appears as thin Cu shells over decahedral Au@Ag cores. Partial reservation of pentagonal shape and appearance of Moire patterns in Au@Ag@Cu particles suggest that epitaxial growth occurs on some parts of the Au@Ag cores despite a large lattice mismatch between Ag and Cu (11.5%). The growth mechanism of Au@Ag@Cu nanocrystals was discussed in terms of lattice mismatch, decahedral particle defects, and the favorable shape of metallic shells. Optical properties of Au@Ag@Cu nanocrystals were determined by measuring extinction spectra.
- Tsuji, Masaharu,Matsunaga, Mika,Kumagai, Hisayo,Ogino, Masatoshi,Hikino, Sachie,Yoshida, Yuki,Ishizaki, Toshitaka
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p. 1345 - 1351
(2013/03/28)
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- Synthesis of gold nanoparticles in presence of ionic liquid [Bmin][CF 3SO3] with humic acid under microwave irradiation and its application as a nanocatalyst
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Gold nanoparticles were synthesized in the presence of ionic liquid [Bmin][CF3SO3] with humic acid for 90 s under microwave irradiation. The resulting gold nanoparticles were confirmed by UV-visible spectroscopy, X-ray diffraction and transmission electron microscopy. The catalytic effect of gold nanoparticles was investigated for the oxidation of 2-hydroxybenzyl alcohol to produce 2-hydroxybenzaldehyde in the presence of 3-chloroperoxybenzoic acid and hydrogen peroxide in methanol. The reaction was completed after 160 min using these gold nanoparticles as a catalyst and the product was identified by high performance liquid chromatography (HPLC) with UV-visible detector.
- Lee, Seong Eon,Ko, Jeong Won,Ko, Weon Bae
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p. 9949 - 9951
(2014/01/06)
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- PROCESS FOR PREPARING FORMIC ACID
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A process for preparing formic acid by hydrogenation of carbon dioxide in the presence of a tertiary amine (I) and a catalyst at a pressure of from 0.2 to 30 MPa abs and a temperature of from 20 to 200° C., wherein the catalyst is a heterogeneous catalyst comprising gold.
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Page/Page column 7
(2013/02/28)
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- The kinetics of redox reaction of gold(III) chloride complex ions with l-ascorbic acid
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The synthesis of gold nanoparticles consists of several stages, i.e. reduction, nucleation and growth. The most important step in particles formation process is the reduction reaction of Au(III) ions to Au(I). The rate of such reaction determines the rate of nuclei formation, i.e. reduction reaction of Au(I) to Au(0) and thus the rate of nanoparticles formation. In this paper, the kinetics and mechanism of redox reaction between gold(III) chloride complex ions and l-ascorbic acid in the aqueous solution have been carried out using spectrophotometric technique. From the experimentally obtained kinetic curves the rate constants of reaction at different conditions of initial concentrations of reactants, pH, temperature, ionic strength and concentration of chloride ions, were determined. It was found that in strong acidic solution (pH 1.3), the values of enthalpy (ΔH?) and entropy (ΔS ?) of activation were 38.5 kJ/mol and -89.5 kJ/mol K, respectively and at higher pH (pH 2.5) the values of ΔH? and ΔS? were 42.0 kJ/mol and -64.5 kJ/mol K, respectively. Using obtained results, the kinetic equation was determined and corresponding mechanism of reaction was suggested. Obtained data can be useful for calculating time of nuclei formation and consequently for better size control and size distribution of particles, e.g. in a microreactor.
- Luty-B?ocho, Magdalena,Pac?awski, Krzysztof,Wojnicki, Marek,Fitzner, Krzysztof
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p. 189 - 196
(2013/06/05)
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- Au microparticles mediated construction of a logic based dual channel molecular keypad lock
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New melamine based ligand 3 with pyrene as a fluorophore is synthesized and characterized. The sequential addition of Au3+ ions and ascorbic acid to the solution of 3 in EtOH-H2O (9.5 : 0.5 v/v) generates gold microparticles (AuMPs). However, the particle size distribution and fluorescence behaviour on sequential additions are different and contribute to the construction of a new logic based molecular dual channel keypad lock system. The Royal Society of Chemistry 2013.
- Devi, Manisha,Dhir, Abhimanew,Pradeep, Chullikkattil P.
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p. 7514 - 7518
(2013/07/28)
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- Laterally enhanced growth of electrodeposited Au to form ultrathin films on nonconductive surfaces
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We investigated the laterally enhanced growth of electrodeposited Au for fabricating nanogap electrodes. To enhance the lateral growth, we carried out electrodeposition over patterned electrodes onto a SiO2 surface modified with self-assembled monolayers (SAMs) or dendrimers with amine groups. The morphology and thickness of the Au films were controlled by adjusting deposition conditions such as duration, applied potential, and Au ion concentration in the bath. To investigate the mechanism of the laterally enhanced growth, the surface states of SAM- or dendrimer-modified SiO 2 were analyzed by X-ray photoelectron spectroscopy (XPS). The XPS results indicate the existence of organic molecules and Au ions on the SiO 2 surface, which suggests that laterally enhanced growth is induced by the Au ions coordinated on the amine groups of the organic molecules. To further analyze the mechanism of the laterally enhanced growth, we investigated the relationship between the morphology of the laterally enhanced growth of Au and the amount of Au ions on organic molecules. The laterally enhanced growth of Au is expected to be useful for fabricating thin film nanogap electrodes.
- Kobayashi, Chiaki,Saito, Mikiko,Homma, Takayuki
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p. 235 - 243
(2012/07/14)
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- Mechanistic interpretation of CO oxidation turnover rates on supported Au clusters
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Kinetic and isotopic data are used to interpret the mechanistic role of gaseous H2O molecules and of non-reducible (Al2O 3) and reducible (TiO2, Fe2O3) supports on CO oxidation turnovers catalyzed by small Au clusters (2O acts as a co-catalyst essential for O2 activation and for catalyst stability in CO oxidation at near-ambient temperatures, but also inhibits rates via competitive adsorption at higher H2O pressures. The effects of CO, O2, and H2O pressures on CO oxidation turnover rates, the absence of 16O2/18O 2 and 16O2/H218O exchange, and the small H2O/D2O kinetic isotope effects are consistent with quasi-equilibrated molecular adsorption of CO, O 2, and H2O on Au clusters with the kinetic relevance of H2O-mediated O2 activation via the formation of hydroperoxy intermediates (OOH), which account for the remarkable reactivity and H2O effects on Au clusters. These elementary steps proceed on Au clusters without detectable requirements for support interface sites, which are no longer required when H2O is present and mediates O2 activation steps. Rate enhancements by H2O were also observed for CO oxidation on Pt clusters (1.3 nm), which is also limited by O2 activation steps, suggesting H2O-aided O2 activation and OOH species in oxidations involving kinetically-relevant O2 activation. These intermediates have also been proposed to account for the ability of O2/H2O mixtures to act as reactants in alkene epoxidation on Au-based catalysts.
- Ojeda, Manuel,Zhan, Bi-Zeng,Iglesia, Enrique
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- Decamethylferrocene redox chemistry and gold nanowire electrodeposition at salt crystal|electrode|nonpolar organic solvent contacts
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This report describes exploratory experimental findings for electrochemical processes in nonpolar solvents (hexane, toluene, and dichloroethane). Conventional 3 mm diameter glassy-carbon-disk electrodes are used in contact with a crystalline salt electrolyte (ammonium nitrate) immersed in nonpolar solvents. The insoluble salt is employed as a "surface thin film electrolyte", with humidity causing electrical connection from the working electrode to the SCE counter-reference electrode. The organic solvents are employed without intentionally added electrolyte. Humidity in the nonpolar solvents is shown to be essential for the processes to work. The oxidation of decamethylferrocene is demonstrated as a test organometallic redox system. The electrochemical reduction of Au(III) in toluene (solubilized with tetraoctylammonium bromide, TOABr) is employed to demonstrate and visualize the reaction zone around salt crystal|working electrode contact points. Gold nanowire bundle formation is observed, presumably due to an ordered interfacial surfactant microphase at salt|electrode contact points. The triple phase boundary nature of these processes is discussed, and future applications are suggested.
- Watkins, John D.,Hotchen, Christopher E.,Mitchels, John M.,Marken, Frank
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p. 2616 - 2620
(2012/06/04)
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- High performance of carbon nanotubes confining gold nanoparticles for selective hydrogenation of 1,3-butadiene and cinnamaldehyde
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This work reports a striking enhancement of catalytic performance of gold nanoparticles (NPs) with average diameter of 3.2 nm partially (ca. 32-40%) confined in the cavity of carbon nanotubes (CNTs) for the gas-phase hydrogenation of 1,3-butadiene (BD), a
- Zhang, Xin,Guo, Yan Cai,Cheng Zhang, Zhi,Gao, Jin Sen,Xu, Chun Ming
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p. 213 - 226
(2012/10/18)
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- Various metal nanoparticles produced by accelerated electron beam irradiation of room-temperature ionic liquid
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Various metal nanoparticles including base metal were produced by a brief accelerated electron beam irradiation of 1-alkyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)amide room-temperature ionic liquid without a stabilizing agent, which is usually employed so as to prevent aggregation.
- Tsuda, Tetsuya,Sakamoto, Taiki,Nishimura, Yoshitomo,Seino, Satoshi,Imanishi, Akihito,Kuwabata, Susumu
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p. 1925 - 1927
(2012/03/13)
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- Investigation of Au@Pt/C electro-catalysts for oxygen reduction reaction
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Carbon-supported Au@Pt core shell nano-structured catalysts were synthesized by the seed-mediated growth method. The nano-structured catalysts were characterized by UV-vis spectroscopy, X-ray photoelectron spectra (XPS) and transmission electron microscopy (TEM) techniques. The oxygen reduction reaction (ORR) activity of the Au@Pt/C was tested by means of linear sweep voltammetry (LSV) by employing rotating disk electrode (RDE). It revealed that Au@Pt (2:4)/C (atomic ratio) catalyst exhibited the best catalytic activity toward ORR. Au@Pt (2:4)/C proceeded by an approximately four-electron pathway in acid solution, through which molecular oxygen was directly reduced to water. The stability of Au@Pt (2:4)/C is tested by cyclic voltammetry for 500 cycles. The performance of the membrane electrode assembly (MEA) prepared by Au@Pt (2:4)/C as the cathode catalyst in a single proton exchange membrane fuel cell (PEMFC) generated a maximum power density of 479 mW cm-2 at 0.431 V using H2 and O2 at 80 °C.
- Lin, Rui,Zhang, Haiyan,Zhao, Tiantian,Cao, Chunhui,Yang, Daijun,Ma, Jianxin
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p. 263 - 268
(2012/03/13)
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- Preferential oxidation of carbon monoxide in hydrogen using zinc oxide photocatalysts promoted and tuned by adsorbed copper ions
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Preferential oxidation of CO (63 Pa) and O2 (76 Pa) in H 2 (6.3 kPa) using spheroidal ZnO nanoparticles (22 nm × 47 nm) converted 52% of CO into CO2, and selectivity to CO2 was 92 mol% under UV-visible light for 5 h. When 0.5 wt.% of Cu2+ was adsorbed on ZnO, 91% of CO was converted into CO2 with a selectivity of 99 mol% under UV-visible light for 3 h. CO (63 Pa) was photocatalytically decreased to 2.3 mPa (0.35 ppm) in O2 (150 Pa) and H2 (6.3 kPa) for 5 h with a selectivity of 94 mol%. As evident from a XANES peak at 8983.1 eV, the surface CuII sites trapped photogenerated electrons. Furthermore, O2-derived species were reduced by accepting electrons from CuI and protons from the neighboring formate species, as indicated by the FT-IR peaks at 2985, 2879, 1627, 1587, and 1297 cm -1.
- Yoshida, Yusuke,Mitani, Yu,Itoi, Takaomi,Izumi, Yasuo
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p. 190 - 202
(2012/04/23)
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- Electrochemical synthesis of mesoporous Pt-Au binary alloys with tunable compositions for enhancement of electrochemical performance
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Mesoporous Pt-Au binary alloys were electrochemically synthesized from lyotropic liquid crystals (LLCs) containing corresponding metal species. Two-dimensional exagonally ordered LLC templates were prepared on conductive substrates from diluted surfactant solutions including water, a nonionic surfactant, ethanol, and metal species by drop-coating. Electrochemical synthesis using such LLC templates enabled the preparation of ordered mesoporous Pt-Au binary alloys without phase segregation. The framework composition in the mesoporous Pt-Au alloy was controlled simply by changing the compositional ratios in the precursor solution. Mesoporous Pt-Au alloys with low Au content exhibited well-ordered 2D hexagonal mesostructures, reflecting those of the original templates. With increasing Au content, however, the mesostructural order gradually decreased, thereby reducing the electrochemically active surface area. Wide-angle X-ray diffraction profiles, X-ray photoelectron spectra, and elemental mapping showed that both Pt and Au were atomically distributed in the frameworks. The electrochemical stability of mesoporous Pt-Au alloys toward methanol oxidation was highly improved relative to that of nonporous Pt and mesoporous Pt films, suggesting that mesoporous Pt-Au alloy films are potentially applicable as electrocatalysts for direct methanol fuel cells. Also, mesoporous Pt-Au alloy electrodes showed a highly sensitive amperometric response for glucose molecules, which will be useful in next-generation enzyme-free glucose sensors.
- Yamauchi, Yusuke,Tonegawa, Akihisa,Komatsu, Masaki,Wang, Hongjing,Wang, Liang,Nemoto, Yoshihiro,Suzuki, Norihiro,Kuroda, Kazuyuki
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p. 5100 - 5109
(2012/05/04)
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- Electrochemical deposition of Zn3P2 thin film semiconductors based on potential-pH diagram of the Zn-P-H2O system
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In this paper, we report on our attempt to make a thin film of Zn 3P2 compound semiconductor by electrodeposition from aqueous solutions containing zinc and phosphorus species. First of all, we constructed the potential-pH diagram of the Zn-P-H2O system at 363 K and found out the wide stable region of Zn3P2 at lower potentials. In the cyclic voltammetry on SnO2 glass substrate, two cathodic current changes and an anodic peak were observed. This is similar results to Soliman, where the electrodeposition of Zn3P2 was succeeded. Consequently, the potentiostatic electrolysis thus was carried out to clarify the reduced substance and the reduction of SnO2 was only observed. When Au electrode was used as an inert electrode, the formation of Zn3P2 was not also observed, while the Au-Zn compound was confirmed. It is considered that the precipitation of zinc predominantly occurs and the reduction of phosphate ions are kinetically difficult from the results of the cyclic voltammetry.
- Nose, Yoshitaro,Hosokawa, Kouhei,Uda, Tetsuya,Awakura, Yasuhiro
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p. D181-D186
(2012/04/23)
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- Electrodeposition of long gold nanotubes in polycarbonate templates as highly sensitive 3D nanoelectrode ensembles
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Electrodeposition of long and well-defined gold nanotubes in polycarbonate (PC) templates is still a major concern due to pore blockage problems. In the present study, we introduce a novel method for electrodeposition of long gold nanotubes within the pores of PC templates for the first time. In order to deposit gold atoms onto the pore walls preferentially, pore walls were functionalized with a coupling agent. Short and thin Ni nanotubes were then electrodeposited at the bottom of the pores. Gold nanotubes were subsequently electrodeposited at constant potentials and low solution concentrations. The morphology of nanotubes was characterized by electron microscopy and their formation mechanism was discussed in detail. Gold nanotubes were fabricated inside PC template with different lengths even as long as the template thickness which was about 6 μm. Using controlled chemical etching of PC template, three-dimensional gold nanoelectrode ensembles (3D GNEs) were developed which show much higher sensitivity compared to their embedded GNEs counterparts in the presence of Fe2+/Fe3+ redox couple. Cyclic voltammograms show that the sensitivity of 3D GNEs increases with increasing the number of etching cycle.
- Bahari Mollamahalle, Yaser,Ghorbani, Mohammad,Dolati, Abolghasem
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p. 157 - 163
(2012/08/14)
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- Method and Technique Employing a Novel Extractant to Enhance Recovery of Gold and Palladium from Hydrochloric Acid Media
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An extraction component enabling the concurrent recovery of gold and/or palladium selectively from a hydrochloric acid media containing the base metals and other contaminants. The disclosed extractant disclosed eliminates the conventional multi-step process for such extraction by providing for an extraction method which uses a single solvent extraction reagent. Further enhancing the conventional multi step process, the conventional scrubbing stage is eliminated by a single stripping stage. The resulting solutions can be obtained from leaching many types of material such as copper anode slimes, the treatment of scrap such as electronic circuit boards and plating effluents, PGM, or refractory gold ores.
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- One pot biosynthesis of gold NPs using red cabbage extracts
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Red cabbage extract was used as reducing agent and capping agent for the synthesis of gold NPs. The method developed is environmentally friendly and allows the control of NPs shape and size by changing the pH value and the concentration of aqueous red cab
- Lekeufack, Diane D.,Brioude, Arnaud
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p. 1461 - 1464
(2012/03/22)
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- 1H MAS NMR study of cysteine-coated gold nanoparticles
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1H MAS NMR experiments were performed on gold nanoparticles coated with l-cysteine. The experiments show that l-cysteine molecules are zwitterions and support a structural model of cysteine forming two layers. The inner layer is composed of cysteine molecules chemisorbed to the gold surface via the sulfur atom. The outer layer interacts with the chemisorbed layer. The 1H NMR suggests that the cysteine in the outer layer exhibits large amplitude motion about specific carbon-carbon bonds.
- Abraham, Anuji,Ilott, Andrew J.,Miller, Joel,Gullion, Terry
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p. 7771 - 7775
(2012/09/21)
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- One-step continuous synthesis of biocompatible gold nanorods for optical coherence tomography
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We present a novel one-step flow process to synthesize biocompatible gold nanorods with tunable absorption and biocompatible surface ligands. Photothermal optical coherence tomography (OCT) of human breast tissue is successfully demonstrated using tailored gold nanorods designed to have strong absorption in the near-infrared range.
- Sebastian, Victor,Lee, Seung-Kon,Zhou, Chao,Kraus, Martin F.,Fujimoto, James G.,Jensen, Klavs F.
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p. 6654 - 6656
(2012/07/14)
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- Investigation of thermal properties of double complex salts [M(NH3)5Br][AuBr4]2-nH2O, M 5 Rh, Ir
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Novel double complex salts [M(NH3)5Br] [AuBr4]2-nH2O, M =Rh, Ir, have been synthesized and examined. The processes of thermal decomposition of the compounds in inert and reductive atmospheres have been studied and intermediate products identified. Simultaneous thermal analysis with parallel mass-spectrometric analysis of evolved gases (STA-EGA) has been employed for identification of main gaseous products of thermolysis in inertatmosphere. It has been revealed that the final products of decompositi on in inert or reductive atmospheres are fine powders of gold and the corresponding platinum metal with sizes of crystallites 4-40 nm. The possibility of preparation of the metastable solid solution Au0.05Ir0.95 on thermolysis of [Ir(NH3)5Br][AuBr4]2-H2O in inert atmosphere has been demonstrated.
- Semitut, E. Yu.,Plyusnin, P. E.,Shubin, Yu. V.,Veniaminov, S. A.,Korenev, S. V.
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p. 901 - 906
(2012/10/08)
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- Anti-galvanic reduction of thiolate-protected gold and silver nanoparticles
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Unexpected: Anti-galvanic reduction (AGR), that is, metal ions are reduced by more-noble metals, was found in small thiolated gold (see figure) and silver nanoparticles! These findings are not only unexpected considering the classic galvanic theory, but also provide a facile and mild method to make alloys on the nanoscale or tune the compositions, structures, and properties of nanostructures that are otherwise difficult to obtain. Copyright
- Wu, Zhikun
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p. 2934 - 2938
(2012/04/17)
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- Ligand effects and ligand design in homogeneous gold(I) catalysis
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Gold catalysis is considered one of the most important breakthroughs in organic synthesis during the past decade, but a rational understanding of ligand effects in gold catalysis is lacking. Most gold-catalyzed reactions go through three major stages: (i) electronic activation of alkyne (or allene) to generate a vinyl gold intermediate; (ii) protodeauration to generate the product and regenerate the cationic gold catalyst; (iii) decay of the active gold catalyst. Our research provides a clearer understanding of how ligands influence each of the three stages in the gold catalytic cycle. What is even more important, by not focusing on a particular gold-catalyzed reaction, we have been able to categorize most gold-catalyzed reactions and propose a ligand design protocol for each category of gold-catalyzed reactions.
- Wang, Weibo,Hammond, Gerald B.,Xu, Bo
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p. 5697 - 5705
(2012/06/04)
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- PEPTIDE-CARRYING NANOPARTICLES
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Nanoparticles having a core and a corona of ligands covalently linked to the core, wherein peptides are bound to or associated with the nanoparticles.
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- Fixation modes of gold(III) from solutions using cadmium(II) dithiocarbamates. Preparation, supramolecular structure and thermal behaviour of polynuclear and heteropolynuclear gold(III) complexes: Bis(N,N- dialkyldithiocarbamato-S,S′)gold(III) polychlorometallates
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Four novel heteropolynuclear and polynuclear complexes of the general formulae [Au(S2CNR2)2]2X (X = [CdCl4]2-, R = CH3 (1); X = [Cd 2Cl6]2-, R = C3H7 (2)) and [Au(S2CNR2)2][AuCl4] (R = iso-C3H7 (3); R = iso-C4H9 (4)) were prepared using heterogeneous reactions between appropriate freshly precipitated binuclear cadmium(II) dialkyldithiocarbamates and AuCl3 in 2 M hydrochloric acid. The isolated complexes were studied by 13C CP/MAS NMR spectroscopy, single-crystal X-ray diffraction and simultaneous thermal analysis (STA) under an argon atmosphere. In all molecular structures (1-4), one of the gold atoms coordinates two dialkyldithiocarbamate ligands in the S,S′-bidentate mode, forming a square-planar coordination polygon [AuS4], while the other gold atom (in 3 and 4) has four neighbouring chlorine atoms [AuCl4]. At the supramolecular level, compounds 1 and 2 comprise binuclear cations, [Au2{S2CN(CH 3)2}4]2+ and polynuclear chains, ([Au{S2CN(C3H7)2}2] +)n in a combination with [CdCl4]2- and [Cd2Cl6]2- anions, respectively. Unexpected structural distinctions at the supramolecular level were discovered for the chemically related compounds 3 and 4. In these ionic complexes, there are either cationic trinuclear formations, {[Au{S2CN(iso-C3H 7)2}2]2[AuCl4]} +, or polynuclear chains, ([Au{S2CN(iso-C 4H9)2}2]+)n, both combined with [AuCl4]- anions, in the structural basis of compounds 3 and 4, respectively.
- Rodina, Tatyana A.,Ivanov, Alexander V.,Gerasimenko, Andrey V.,Loseva, Olga V.,Antzutkin, Oleg N.,Sergienko, Valentin I.
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- Au-Ag Core-Shell Nanorod Particles and Method for Producing Same
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Disclosed are: Au—Ag core-shell nanorod particles wherein a cationic surfactant such as CTAB is substituted by an other compound; and a method for producing the Au—Ag core-shell nanorod particles. Specifically disclosed are Au—Ag core-shell nanorod particles which are characterized in that each of the nanorod particles comprises a gold nanorod particle that serves as the core, a shell layer that covers the surface of the gold nanorod particle and is formed from silver, and a copolymer that adsorbs on the surface of the shell layer. The Au—Ag core-shell nanorod particles are also characterized in that the copolymer is a block copolymer or graft copolymer that is obtained by polymerizing at least a polymerizable monomer (A) that has a group represented by general formula (I). In the formula, Ra represents an alkylene group having 2-7 carbon atoms.
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- Chemical, spectroscopic characterization, DFT studies and antibacterial activities in vitro of a new gold(I) complex with rimantadine
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A novel gold(I) complex with rimantadine (RTD) was obtained and structurally characterized by a set of chemical and spectroscopic analysis. 1H, 13C and 15N nuclear magnetic resonance (NMR) and infrared (IR) spectroscopic measurements suggest coordination of the ligand to Au(I) through the N atom of the ethanamine group. Theoretical (DFT) calculations confirmed the IR assignments and permit proposing an optimized geometry for the complex. The gold(I)-rimantadine complex (Au-RTD) is soluble in methanol, ethanol, dimethylsulfoxide, acetone and acetonitrile. The preliminary kinetic studies based on UV-vis spectroscopic measurements indicate the stability of the compound in solution. Antibacterial activities of the complex were evaluated by an antibiogram assay. The Au-RTD complex showed an effective in vitro antibacterial activity against the Pseudomonas aeruginosa, Escherichia coli (Gram-negative), and Staphylococcus aureus (Gram-positive) bacterial strains.
- Sucena, Suelen F.,Paiva, Raphael E.F.,Abbehausen, Camilla,Mattos, Ives B.,Lancellotti, Marcelo,Formiga, André L.B.,Corbi, Pedro P.
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p. 114 - 118
(2012/03/22)
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