- Temperature-programmed reduction study on calcination of nano-palladium
-
Pd membranes with high mechanical strengths are used to purify hydrogen in industrial scale for feedstock in petrochemical processes. The effects of calcinations treatment on samples of mono-metallic Pd and Pd77-Ag23 alloy with primary particles ～ 8 nm were studied with the TPR technique. A hydrogen-consumption at low temperature and a hydrogen-desorption at high temperature were observed from obtained TPR traces. The extent of oxidation on both samples increased with the calcinations temperature, i.e., oxygen adsorption on the surface of primary particles at To o > 573 K. The temperature required for a reduction of oxidized palladium by hydrogen was generally low. Tr = 150 K for oxygen chemisorbed on nano-palladium but raised over 260 K for oxide anions in the PdO structure. Primary particles of nano-palladium retained their size of 8 nm upon calcinations at To o > 673 K. Incorporation of oxygen into sublayers of Pd crystallites was promoted by alloy with silver.
- Yeh,Chu,Sheen,Chiang,Chou,Perng,Huang,Lee
-
-
Read Online
- Low-temperature synthesis of single crystalline Ag2S nanowires on silver substrates
-
We report on the successful synthesis of silver sulfide (Ag2S) nanowires by a simple and mild gas - solid reaction approach. For the nanowire synthesis, a preoxidized silver substrate is exposed to an atmosphere of an O2/H2S mixture at room temperature or slightly above. The resulting Ag2S nanowires are phase pure with a monoclinic crystal structure and have diameters of a few tens of nanometers and lengths up to 100 ??m. The influence of reaction conditions on the diameter, length, and morphology of the Ag2S nanowires has been studied by a number of structural and spectroscopic techniques. The nanowire growth mechanism on the Ag substrate has been discussed, which is likely characterized by continuous deposition at the tip. Additionally, we demonstrate thinning and cutting of individual Ag2S nanowires with electron beams and laser beams, which are potentially useful for nanowire manipulation and engineering. ? 2005 American Chemical Society.
- Wen, Xiaogang,Wang, Shuhua,Xie, Yutao,Li, Xiao-Yuan,Yang, Shihe
-
-
Read Online
- Kinetic study of the reactions of gas phase Pd(a1S0), Ag(5s 2S1/2), Au(6s 2S1/2), Cd(5s2 1S0, and Hg(6s2 1S0) atoms with nitrous oxide
-
The reactivity of gas-phase Pd(a1S0), Ag(5s 2S1/2), Au(6s 2S1/2), Cd(5s2 1S0), and Hg(6s2 1S0) with N2O as a function of temperature and pressure is reported. The transition metal atoms were produced by the photodissociation of an appropriate precursor molecule and detected by laser-induced fluorescence. The reaction of palladium with N2O is pressure dependent indicating adduct formation. The room-temperature limiting low-pressure third-order rate constant is (2.5 ± 0.8) × 10-30 molecule-2 cm6 s-1 in argon buffer. The limiting low-pressure third-order rate constant can be expressed as log k0(T) = -219.06 + 152(log T) - 30.5(log T)2 molecule-2 cm6 s-1 over the temperature range 294-523 K. The reactions of ground-state silver, gold, cadmium, and mercury with N2O are very slow, and only upper limits for the rate constants can be reported for these reactions.
- Campbell, Mark L.
-
-
Read Online
- Skeleton pseudomorphs of nanostructured silver for the surface-enhanced Raman spectroscopy
-
Pseudomorphs (mesocages) of metallic silver were prepared via either a shape-preserving reduction of polyhedral Ag2O precursors with H2O2 in aqueous ammonia or an ultrasonic spray pyrolysis of aqueous diamminesilver(i) hydroxide. Both the materials were revealed as suitable for the direct analysis at 0.1–1 μm concentrations of oil pollutants and pharmaceutical substances using surface-enhanced Raman spectroscopy due to their unique morphology providing either a larger surface area for sorption of analytes or additional ‘hot spots’ resulting in the enhancement factors of 106–108.
- Semenova, Anna A.,Savilov, Sergey V.,Baranchikov, Alexander E.,Ivanov, Vladimir K.,Goodilin, Eugene A.
-
-
Read Online
- Single-crystal-to-single-crystal conversions of two metal-mediated photoreactive coordination polymers based on stereoselective [2 + 2] photocycloaddition reactions
-
Two photoreactive coordination polymers {[Zn(μ-OH2)(5-Me-1,3-bdc)(2,3′-bpe)]·H2O}n (1) and {[Ag2(5-Me-1,3-Hbdc)(2,3′-bpe)2][Ag(5-Me-1,3-bdc)(2,3′-bpe)]·H2O}n (3) have been prepar
- Chen, Jing-Min,Zhou, Qian-Kun,Hou, Yi-Xuan,Liu, Dong
-
-
Read Online
- Recyclable CoFe2O4–Ag2O magnetic photocatalyst and its visible light-driven photocatalytic performance
-
A magnetically separable photocatalyst, the composite compound CoFe2O4–Ag2O, was fabricated successfully by a simple precipitation method and used for photodegradation of organic pollutants under visible light (>420?nm) irradiation. Its magnetic separation performance was evaluated. Results showed that the CoFe2O4–Ag2O with 60-wt% content of Ag2O had the best photocatalytic performance, stability, and magnetic separation performance. Methyl orange, methylene blue, rhodamine B, and phenol can be completely photodegraded by the CoFe2O4–Ag2O photocatalyst in a short period. After five cycles, CoFe2O4–Ag2O kept its performance stability. As prepared, CoFe2O4–Ag2O (60%) has a coercivity of 2500 Oe and a saturation magnetization of 22.45?emu?g?1; it can be completely separated magnetically in 20?s with magnetic recovery mass rate of 85% under an external magnetic field. This superb photocatalytic performance and separation recovery confirms that the CoFe2O4–Ag2O photocatalyst is a promising candidate for future use in photo-oxidative degradation of organic contaminants.
- Zeng, Qihui,Zhu, Yingming,Tian, Wen,Jiang, Wei,Liang, Bin
-
-
Read Online
- Direct synthesis of AgInO2
-
Potential applications as transparent conducting oxides have made the study of ternary metal oxides based on the delafossite structure very attractive. The well known and understood thermal instability of noble metal oxides, and therefore the associated problems with high-temperature solid-state techniques to yield pure complex oxides based on noble metals, clearly illustrates the need for low-temperature alternatives. For the first time, synthesis of 3R-AgInO2 at low temperature (175 °C) and pressure (a single-step hydrothermal technique. Particle size of the orange crystallites ranged from 3 to 7 μm.
- Shahriari, Dean Y.,Erdman, Natasha,Haug, Ulrika T.M.,Zarzyczny, Matthew C.,Marks, Lawrence D.,Poeppelmeier, Kenneth R.
-
-
Read Online
- Performance promotion of Ag2O photocatalyst by particle size and crystal surface regulation
-
The insufficient photocatalytic performance of Ag2O makes it difficult to apply to actual industrial printing and dyeing waste water treatment systems, which contain a variety of organic pollutants. Therefore, it is urgent to improve the photocatalytic performance of Ag2O. In this study, the main factors affecting the properties of Ag2O photocatalysts were screened out by single factor experiments. Then, the optimum conditions for the preparation of Ag2O were simulated by response surface design. The prepared Ag2O showed good photodegradation performance to methyl orange and phenol, but the degradation of rhodamine B was significantly delayed. After that, the pyridine was introduced to adjust the crystal plane structure of Ag2O. The results showed that the photocatalytic oxidation capacity of Ag2O was greatly improved. Ninety percent of rhodamine was removed within 25 minutes. Moreover, the mechanism of controlling the photocatalytic performance has also been studied through fine characterizations.
- Fu, Hongyan,He, Jian,Jiang, Wei,Lin, Zehao,Wu, Pan,Zeng, Ya
-
-
Read Online
- Preparation of POSS-poly(ε-caprolactone)-β-cyclodextrin/Fe3O4hybrid magnetic micelles for removal of bisphenol A from water
-
A novel amphiphilic star-shaped inorganic-organic hybrid copolymer polyhedral oligomeric silsesquioxane-poly(ε-caprolactone)-β-cyclodextrin (POSS-PCL-β-CD) was synthesized by ring-opening polymerization (ROP) and click chemistry. The amphiphilic copolymer can self-assemble into hybrid micelles with hydrophobic POSS-PCL chain encapsulating Fe3O4nanoparticles as the core and β-CD as the shell after mixing with Fe3O4nanoparticles in solvent and dialysis against water. The chemical structure of POSS-PCL-β-CD was characterized by 1H NMR and the morphology of the magnetic hybrid micelles was characterized by TEM and DLS. Due to the host-guest interaction of β-CD with bisphenol A (BPA), POSS-PCL-β-CD/Fe3O4hybrid micelles present good adsorption capacity in removal of BPA from aqueous solution. Magnetic measurement reveals that POSS-PCL-β-CD/Fe3O4hybrid micelles still exhibit magnetism for separation by an external magnetic field, indicating that these magnetic hybrid micelles may have potential application in the field of environmental protection.
- Yuan, Weizhong,Shen, Jin,Li, Lulin,Liu, Xu,Zou, Hui
-
-
Read Online
- Operando Synthesis of a Dendritic and Well-Crystallized Molybdenum Oxide/Silver Catalyst for Enhanced Activity in the Hydrogen Evolution Reaction
-
Dendritic MoO3/Ag with good crystallinity has been prepared through an operando method. In the hydrogen evolution reaction (HER), this catalyst, which was designed to utilize the best properties of each component material, showed a high catalytic activity. After the precursor was drop-cast onto a glassy carbon electrode, a reductive potential was applied to the coated electrode, and H2 evolution occurred within the range of potentials. The overpotential required to evolve H2 at the benchmark rate decreased progressively with subsequent voltammetric cycles, until a steady state was reached at which only 145 mV of overpotential was required to pass -10 mAcm-2 of current density. During the electrocatalysis, the precursor was converted to catalyst through an operando method. This operando-synthesized MoO3/Ag catalyst has a low Tafel slope (43 mVdec-1), low overpotential (145 mV), and excellent durability for HER. It has the potential to be a promising material for HER. Operando star: A dendritic MoO3/Ag composite with good crystallinity is prepared through an operando method and it exhibited excellent catalytic properties in the hydrogen evolution reaction.
- Xia, Xiaohong,Shen, Xuan,Zhao, Xiaojuan,Ye, Weichun,Wang, Chunming
-
-
Read Online
- Characteristics of silver ions exchanged in ZSM-5-type zeolite, aluminosilicate, and SiO2 samples: In comparison with the properties of copper ions exchanged in these materials
-
The characteristics of silver ions exchanged in ZSM-5-type zeolite, aluminosilicate, and SiO2 samples were discussed. The IR technique in combination with adsorption microcalorimetry was used to analyze the bonding nature of silver ion exchange
- Kuroda, Yasushige,Onishi, Hideo,Mori, Toshinori,Yoshikawa, Yuzo,Kumashiro, Ryotaro,Nagao, Mahiko,Kobayashi, Hisayoshi
-
-
Read Online
- Metal-controlled assembly tuning the topology and dimensionality of coordination polymers of Ag(I), Cd(II) and Zn(II) with the flexible 2-(1H-imidazole-1-yl)acetic acid (Hima)
-
Three new, inorganic-organic coordination polymers based on a versatile linking unit 2-(1H-imidazole-1-yl)acetate (ima) and AgI, CdII and ZnII ions, exhibiting one to three dimensionalities and different topology structures, have been prepared in water medium and structurally characterized by single-crystal X-ray diffraction analysis. Reaction of AgNO3 with Hima afforded a neutral one-dimensional (1-D) chains [Ag(ima)]n (1) which exhibits a pseudo two-dimensional (2-D) layered architecture through π-π stacking interaction between imidazole rings and intermolecular Ag?Ag interactions. Reaction of CdCl2 with Hima yielded neutral 2-D coordination polymers [Cd(ima)2]n (2) possessing (6, 3) topology structures, which further stack into 3-D supramolecular networks through C-H?O weak interactions. While Zn(NO3)2 was used, a non-centric 3-D coordination polymer [Zn(ima)2]n (3) featuring a 3-fold interpenetrating diamondoid net was isolated. Among these polymers, the building block ima anion exhibits different coordination modes. These results indicate that the versatile nature of this flexible ligand, together with the coordination preferences of the metal ions, play a critical role in construction of these novel coordination polymers. The spectral, thermal and SHG (second-harmonic generation) properties of these new materials have also been investigated.
- Wang, Yong-Tao,Tang, Gui-Mei,Wu, Yue,Qin, Xu-Yan,Qin, Da-Wei
-
-
Read Online
- Stable supercapacitor electrode based on two-dimensional high nucleus silver nano-clusters as a green energy source
-
Atomically precise silver nanoclusters (Ag-NCs) are known as a hot research area owing to their brilliant features and they have attracted an immense amount of research attention over the last year. There is a lack of sufficient understanding about the Ag-NC synthesis mechanisms that result in optimal silver nanoclusters with an appropriate size, shape, and morphology. In addition, the coexisting flexible coordination of silver ions, the argentophilic interactions, and coordination bonds result in a high level of sophistication in the self-assembly process. Furthermore, the expansion of clusters by the organic ligand to form a high dimensional structure could be very interesting and useful for novel applications in particular. In this study, a novel two-dimensional 14-nucleus silver poly-cluster was designed and synthesized by the combination of two synthetic methods. The high nucleus silver cluster units are connected together via tetradecafluoroazelaic acid (CF2) and this leads to the high stability of the polymer. This highly stable conductive poly-cluster, with bridging groups of difluoromethylene, displays a high energy density (372 F g-1 at 4.5 A g-1), excellent cycling stability, and great capacity. This nanocluster shows a high power density and long cycle life over 6000 cycles (95%) and can also tolerate a wide range of scan rates (5 mV s-1 to 1 V s-1), meaning it could act as a green energy source. This journal is
- Zhuge, Jing,Rouhani, Farzaneh,Bigdeli, Fahime,Gao, Xue-Mei,Kaviani, Hamed,Li, Hong-Jing,Wang, Wei,Hu, Mao-Lin,Liu, Kuan-Guan,Morsali, Ali
-
-
Read Online
- Highly efficient top-emitting organic light-emitting diodes with self-assembed monolayer-modified Ag as anodes
-
A series of p -substituted benzylmercaptans was used to form self-assembled monolayers (SAMs) on silver surface to serve as the anode in the fabrication of top-emitting organic light-emitting diodes. SAMs with electron-withdrawing substituents such as cyano and trifluoromethyl groups led to enhanced hole injection and electroluminescent performance, whereas the opposite is true for electron-donating groups. Direct quantitative correlation between the molecular dipole moment/work function or work function/hole injection does not exist. A high current efficiency of ～12 cdA was obtained, which is two and half times that of the conventional bottom-emitting device of the same layer structure.
- Hung, Ming-Chin,Wu, Kun-Yang,Tao, Yu-Tai,Huang, Hung-Wei
-
-
Read Online
- DECOMPOSITION OF AGO IN ALKALINE SOLUTIONS
-
Since AgO is mainly used in sealed cells, it is very important to know its gassing rate is the absence or presence of beneficial or detrimental additives. The gassing, i. e. , decomposition rate of AgO samples (prepared by chemical oxidation of AgNO//3) was determined in alkaline electrolytes as a function of time, NaOH concentration, temperature, porosity, surface area, pelletizing pressure, and intentionally added inorganic additives. The presence of 1000 ppm (Ag) Co, Ni, and Zr is catastrophic from the viewpoint of decompoition, and samples with Ce, Pd and W have intolerable large gassingrates. Sn, Ge, and especially Pb suppressed the large gassing rates of AgO samples regardless whether they were incorporated with 5 ppm (Ag) Ni during their prep%aration or only added to the alkaline solutions. It is advantageous to have Pb as one of the components in any combination of beneficial additives.
- TVARUSKO A
-
-
Read Online
- Growth of silver nanowires on metal plates by conventional redox displacement
-
Silver nanowires (diameter 20-50 nm, length of the order of μm) have been synthesized in a high yield from nitric acid-treated iron plates dipped in a silver nitrate solution of an appropriate concentration. The formation of the silver nanowires is discussed in terms of silver nitrate concentration, substrate surface morphology and elemental nature of substrate.
- Jiang, Zhi-Yuan,Xie, Zhao-Xiong,Zhang, Shu-Hong,Xie, Su-Yuan,Huang, Rong-Bin,Zheng, Lan-Sun
-
-
Read Online
- New complexes constructed from: In situ nitration of (1 H -tetrazol-5-yl)phenol: Synthesis, structures and properties
-
Nine new complexes, {[Zn3(L1)2(OH)2]·H2O}n (1), [Ag2(L1)]n (2), {[Co(HL1)2(H2O)4]·2H2O} (3), [Cu3(L1)2(OH)2(H2O)]n (4), {[Cu7(HL1)2(L1)6(H2O)6]·11.1H2O}n (5), {[Cu(L1)(H2O)3]·8H2O}n (6), [Ag2(L2)]n (7), [Ag8(L3)4(H2O)]n (8) and [Cu(L3)(H2O)2]n (9) [H2L1 = 2,6-dinitro-4-(1H-tetrazol-5-yl)phenol, H2L2 = 2,4,6-trinitro-3-(1H-tetrazol-5-yl)phenol, H2L3 = 2,4-dinitro-6-(1H-tetrazol-5-yl)phenol], have been solvothermally synthesized via in situ nitration from 4-(1H-tetrazol-5-yl)phenol, 3-(1H-tetrazol-5-yl)phenol and 2-(1H-tetrazol-5-yl)phenol precursors as well as nitrate salts as nitration reagents and structurally characterized by single-crystal X-ray diffraction, infrared spectroscopy (IR), elemental analysis, powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA). The structures of the complexes vary from 3D frameworks for 1, 4 and 7, 2D networks for 2, 5 and 8, 1D chains for 6 and 9, to a discrete 0D structure for 3, showing 2D supramolecular structures by interlayer π-π stacking. Topological classification of 2D and 3D architectures was performed, disclosing a variety of topological symbols: (42·6)2(44·62·88·10) for 1, (43)2(46·66·83) for 2, (46)2(412·612·84) for 4, (63) for 5 and (45·6)(47·63)(418·616·82) for 7. The contrast of 1-9 reveals that ligands and metal salts have important influences on adjusting the crystal structures; notably, the coordination modes of the ligands can also tune the structures of 4-6 which possess the same ligands and nitration agents. The solid-state UV-vis spectra and band gap energy of the nine complexes were investigated. In addition, the luminescence properties (for complexes 1-3, 7 and 8) and magnetic properties (for complexes 3-6 and 9) were also discussed.
- Du, Ceng-Ceng,Wang, Xin-Fang,Zhou, Sheng-Bin,Wang, Duo-Zhi,Jia, DIanzeng
-
-
Read Online
- β-Ag3RuO4, a Ruthenate(V) Featuring Spin Tetramers on a Two-Dimensional Trigonal Lattice
-
Open-shell solids exhibit a plethora of intriguing physical phenomena that arise from a complex interplay of charge, spin, orbital, and spin-state degrees of freedom. Comprehending these phenomena is an indispensable prerequisite for developing improved functional materials. This type of understanding can be achieved, on the one hand, by experimental and theoretical investigations into known systems, or by synthesizing new solids displaying unprecedented structural and/or electronic features. β-Ag3RuO4 may serve as such a model system because it possesses a remarkable anionic structure, consisting of tetrameric polyoxoanions (Ru4O16)12-, and is an embedded fragment of a 2D trigonal MO2 lattice. The notorious frustration of antiferromagnetic (AF) exchange couplings on such lattices is thus lifted, and instead strong AF occurs within the oligomeric anion, where only one exchange path remains frustrated among the relevant six. The strong magnetic anisotropy of the [Ru4O16]12- ion, and the effectively orbital nature of its net magnetic moment, implies that this anion may reveal the properties of a single-molecule magnet if well-diluted in a diamagnetic matrix.
- Prasad, Beluvalli E.,Kazin, Pavel,Komarek, Alexander C.,Felser, Claudia,Jansen, Martin
-
-
Read Online
- Synthesis and crystal structure analysis of KAg11(VO 4)4
-
New potassium silver vanadate KAg11(VO4)4 was obtained by reacting the stoichiometric mixture of Ag2O and V2O5 at elevated oxygen pressure, adding a small portion of aqueous KOH. The synthesis was done at 573 K and 430 MPa of oxygen pressure. The crystal structure was solved by direct methods basing on single crystal diffraction data (Pbca, Z = 4, a = 16.533(1), b = 10.6286(7), c = 10.5452(7) A, 3983 independent reflections, R1 = 5.4%). The optical band gap for KAg11(VO4)4 was determined as 2.0 eV. According to magnetic measurements, KAg11(VO4)4 is diamagnetic.
- Kovalevskiy, Anton,Jansen, Martin
-
-
Read Online
- AgCuO2 - Synthesis, crystal structure, and structural relationships with CuO and AgIAgIIIO2
-
The new silver cuprate AgCuO2 was synthesized by applying a low-temperature route. AgCuO2 precipitates as a microcrystalline black and thermally labile powder from concentrated aqueous solutions of copper and silver nitrate under alkaline and oxidizing conditions. Using the positional parameters of AgAgO2 as a starting set, Rietveld refinements have been performed using X-ray and neutron powder data (P21/c, a = 5.8657(3), b = 2.8062(2), and c = 6.0770(3)A, β = 108.106(4)°, Z = 2, Rp = 6.61%, Rwp = 5.00% for joint refinement). The crystal structure consists of chains of ladder-like CuO4 rectangles running along [010], interconnected by AgO2 dumbbells. For physical and crystal chemical reasons the oxidation states + I for silver and + III for copper, respectively, have been assigned. Similar to AgAgO2 and CuO the metal cations form a fcc structure with oxygen at positions slightly displaced from the centers of the octahedral vacancies. The small differences from the AgAgO2 structure can be traced back to a different off-center position in the octahedral void.
- Curda,Klein,Jansen
-
-
Read Online
- Silver coordination polymers with tri- and hexacyanoethyl-functionalized macrocyclic ligands
-
Tri- and hexa-cyanoethyl functionalized 17- (L1) and 42-membered (L2) macrocyclic compounds were obtained by [1 + 1] (for L1) or [2 + 2] (for L2) cyclocondensation of the corresponding dialdehyde and diethylenetriamine, followed by hydrogenation by KBH4 and subsequent cyano-functionalization with acrylonitrile. They react with silver nitrate, leading to the formation of [AgL1](NO3) (1) and of the metal-organic coordination polymers [Ag2(NO3)2L1]n (2) and {[Ag2L2](NO3)2}n (3). The complexes were characterized by elemental analysis, 1H NMR, 13C NMR, IR spectroscopies, and ESI-MS; moreover, L2, 1, 2 and 3 were also characterized by single crystal X-ray diffraction. The metal cation in 1 is pentacoordinated with a N3O2 coordination environment; in 2, the metal cations display N4O2 octahedral and N2O3 square-pyramid coordination and in 3 they are in square-planar N4 sites. In 1, the ligand acts as a pentadentate chelator, and in the other two cases, the ligands behave as octadentate chelators in a 1κ3N:κ2O,2κN,3κN,4κN (in 2) or 1κ3N,2κ3N,3κN,4κN fashion (in 3). The cyanoethyl strands of the ligands are directly involved in the formation of the 2D frameworks of 2 and 3, which in the former polymer can be viewed as a net composed of hexametallic 36-membered macrocyclic rings and in the latter generates extra hexametallic 58-membered cyclic sets that form zig-zag layers. The thermal analytical and electrochemical properties of these silver complexes were also studied. This journal is
- Ma, Zhen,Shi, Huaduan,Deng, Xiuqiang,Guedes Da Silva, M. Fátima C.,Martins, Luísa M. D. R. S.,Pombeiro, Armando J. L.
-
-
Read Online
- Pentamethylcyclopentadienyl-rhodium and -iridium Complexes. Part 29. Syntheses and X-Ray Structure Determinations of 2(OH)3>OH*11H2O and 2(OH)3>O2CMe*14H2O and Related Complexes
-
The complexes 2(OH)3>X*nH2O (M=Rh, X=Pf6 and OH; M=Ir, X=O2CMe, OH, and BPh4) have been prepared.Single-crystal X-ray determinations have been carried out on 2(OH)3>OH*11H2O (2c) and on 2(OH)3>O2CMe*14H2O (3a).Both show two metal atoms each η-bonded to a C5Me5 ligand and bridged by three hydroxo-ligands with Rh...Rh 2.973 8(8) Angstroem, Ir...Ir 3.070 9(7) Angstroem, Rh-O (mean) 2.120 Angstroem, Rh-O-Rh (mean) 89.6(1) deg, and Ir-O-Ir (mean) 92.8(3) deg.Both (2c) and 2(OH)3>OH*nH2O are very strong bases in water.Reaction of 2Cl4> (1) with Ag2SO4 gave Rh(C5Me5)(SO4)*2H2O which probably exists in water as the dication (2+) and which is quantitatively carbonylated (20 deg C, 1 atm, 48 h) to .The carbonatocomplex Rh(C5Me5)(CO3)*2H2O was obtained from (1) and Ag2CO3 or by air-oxidation of 2(CO)2>.Reaction of 2(OH)3>Cl with P(OMe)3 gave the unexcepted methylrhodium complex 2>(+) as well as 3>(2+).
- Nutton, Andrew,Bailey, Pamela M.,Maitlis, Peter M.
-
-
Read Online
- Syntheses, crystal structures and fluorescent properties of Cd(II), Hg(II) and Ag(I) coordination polymers constructed from 1H-1,2,4-triazole-1-acetic acid
-
Three new d10 coordination polymers, namely [Cd(taa)Cl]n 1, [Hg(taa)Cl]n 2, and [Ag1.5(taa)(NO3)0.5]n 3 (taa=1H-1,2,4-triazole-1-acatate anion) have been prepared and characteriz
- Ding, De-Gang,Xie, Li-Xia,Fan, Yao-Ting,Hou, Hong-Wei,Xu, Yan
-
-
Read Online
- Ag(I) coordination polymers with flexible bis-imidazole ligands: 2D interwoven structure and wavy layer network based on silver-silver interactions
-
Two new coordination polymers [Ag(BIM)SO3CF3]n (1) and [Ag(2-mBIM)NO2]n (2) [wherein BIM = bis(imidazol-1-yl)-methane, 2-mBIM = bis(2-methylimidazol-1-yl) methane], were synthesized by the reactions o
- Jin, Chuan-Ming,Chen, Zhan-Fen,Mei, Hong-Fei,Shi, Xi-Kui
-
-
Read Online
- A cagelike polyanion with a Ag+ enwrapped, [AgAs 2Mo15O54]11-
-
The polyanion [AgAs2Mo15O54]11- has an unusual cage-like structure composed of [AsMo6O 27]15- and [AsMo6O24]9- subunits connected by three MoO4 tetrahedra, and a Ag+ cation is inclosed at the center of the cage and coordinated by two As atoms with a As-Ag-As bond angle of 180° along with three μ3-oxo groups from MoO4 tetrahedra to lead to a trigonal-pyramidal coordination geometry. The compound was also characterized by IR, X-ray photoelectron spectroscopy, fluorescent spectroscopy, and thermogravimetry- differential scanning calorimetry. The stability of [AgAs2Mo 15O54]11- in aqueous solution was investigated by using electronic absorbance spectroscopy and electrospray ionization mass spectrometry.
- Zhang, Yanping,Li, Lili,Sun, Tao,Liu, Bin,Hu, Huaiming,Xue, Ganglin
-
-
Read Online
- Coordination polymer of Ag trifluoroacetate with 2-methylpyrazine: Synthesis and structure of [Ag(CF3CO2)(2-Me-Pyz)]
-
The [Ag(CF3CO2)(2-Me-Pyz)] complex (where 2-Me-Pyz is 2-methylpyrazine) was synthesized and its structure was determined. The crystals are monoclinic, space group P21/n, a = 12.440(2) A, b = 2.605(3) A, c = 12.646(3) A, β = 95.95(3)°, V = 1972.3(7) A3, ρ = 2.122 g/cm3, Z = 8. The structure consists of the polymer zigzag chains of [Ag(C5H6N 2)] - ∞ united into a three-dimensional framework through (CF3CO2)- anions. Nauka/Interperiodica 2006.
- Kokunov,Gorbunova
-
-
Read Online
- A new silver 1D-coordination polymer with bridging 2-aminopyrimidine, synthesis, characterization and antibacterial activity
-
A new silver(?) complex formulated as [Ag(μ-amp)(ONO2)]n (1) (amp = 2-aminopyrimidine) was synthesized and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Its thermal stability was studied by TGA/DTA. The bridging 2-aminopyrimidine ligands connect Ag(I) ions into a polymeric chain extended along the a axis; the chains are connected by nitrate anions and Ag…Ag interactions into 2 D arrays parallel with ac; these arrays are finally connected by hydrogen bonds into a three-dimensional network. In vitro antibacterial activities of 1 on Staphylococcus aureus (ATCC25923), Enterococcus faecalis (ATCC29219), Pseudomonas aeruginosa (ATCC27853) and Escherichia coli (ATCC25922) as important pathogens in producing infection in humans were investigated. Antibacterial activities were studied by determining minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The silver 1 D-coordination polymer with appropriate concentrations has good efficacy on these microorganisms. Escherichia coli is most sensitive to the complex (MIC: 0.009 μg/mL).
- Ahadiat, Ghasem,Tabatabaee, Masoumeh,Gholivand, Khodayar,Zare, Karim,Du?ek, Michal
-
-
Read Online
- Enhancement of ultraviolet emissions from ZnO films by Ag doping
-
The Ag-doped ZnO films were deposited on Si substrates by dc reactive sputtering. Obvious enhancement of ultraviolet (UV) emission of the samples was observed due to Ag2 O nanoclusters formatted during Ag doping. The UV emission consisted of two peaks. The 348 nm peak was attributed to Ag2 O nanoclusters, and the 382 nm one was attributed to ZnO. The strongest UV emission of a certain ZnO- Ag2 O film was over ten times stronger than that of a pure ZnO film, which was an exciting result. The enhancement of UV emission was caused by excitons formed at the interface between Ag2 O nanoclusters and ZnO grains.
- Duan, Li,Lin, Bixia,Zhang, Weiying,Zhong, Sheng,Fu, Zhuxi
-
-
Read Online
- On Ag2SnO3, the first silver stannate
-
For the first time, crystals of red Ag2SnO3 have been obtained by solid state reaction of freshly prepared K2Sn(OH)6 and Ag2O at 430°C while applying an oxygen pressure of 350 bar. Ag2SnO3 shows a one dimensional incommensurate superstructure with a' = 33.1 A?. Here we report on the basic structure of Ag2SnO3. According to the results of X-ray crystal structure determination the basic structure of Ag2SnO3 may be described in P6322 (a = 5.6230(4) A?, c = 12.6694(14) A?, Z = 4, 968 independent reflections, R1 = 5.6%, wR2 = 12.5%). Within the layered 'SnO3' partial structure two third of the octahedral voids are occupied by tin. Those SnO3 layers are connected to each other by almost linearly coordinated silver atoms. Additionally, silver occupies the free octahedral voids within the SnO3 sheets. As expressed by the formula Ag[Ag1/3Sn2/3]O2 the structure may be described as a super structure of Delafossite CuFeO2.
- Linke,Jansen
-
-
Read Online
- Interaction of aqueous iodine species with Ag2O/Ag surfaces
-
The chemical conversion of Ag2 O films on Ag surfaces to AgI in aqueous iodide solutions has been studied electrochemically. Ag2 O films were grown potentiostatically and then exposed to I- solutions. The chemical conversion process was followed at open-circuit potential (EOC) using cathodic stripping voltammetry performed after various exposure periods. The EOC showed a sudden drop at the completion of the conversion of Ag2 O to AgI, reaching a steady-state value close to the equilibrium potential for AgIAg and the iodide solution. This sudden drop in EOC allowed easy determination of the total reaction time required for complete conversion of Ag2 O to AgI. Distinctly separated current peaks were observed for the cathodic reduction of Ag2 O and AgI to Ag, and the charges associated with these peaks provided a measure of the amount of Ag2 O converted. The conversion reaction was 100% efficient. The total reaction times from the EOC measurements and the cathodic stripping results were used to determine the reaction order and rate constant required for the development of nuclear reactor safety assessment codes.
- Zhang,Stewart,Shoesmith,Wren
-
-
Read Online
- Reactivity and structural properties of a mechanochemically treated Ag2O-V2O5 system in relation to AgVO3 polymorphs
-
Formation and chemical properties of amorphous AgVO3, which was prepared by mechanochemical treatment of an Ag2O-V2O5 mixture, and crystalline AgVO3 were studied in relation to AgVO3 polymorphs. A ball-milled sample of the mixture was assigned as a highly deformed β-AgVO3 rather than the Iow density phase α-AgVO3. Crystalline α-AgVO3 and β-AgVO3 were converted into deformed β-AgVO3 by ball milling, which produced a clear change. δ-AgVO3 is resistant to mechanical treatment and its structure was not markedly affected. The dissolved chemical species from the ball-milled sample precipitates to form α-AgVO3 without a seeding crystal, but other polymorphs deposit if they are present; i.e., β-AgVO3 and δ-AgVO3 grow on the seeding crystal.
- Kittaka, Shigeharu,Nishida, Sachie,Iwashita,Ohtani, Tsukio
-
-
Read Online
- Electrochemical deintercalation of Ag5Pb2O 6
-
Silver was deintercalated out of the layered silver plumbate Ag 5Pb2O6 via coulometric titration at different temperatures (25-310°C) in electrochemical cells like Ag/AgNO3 in CH3CN (0.1 mol/L)/Ag5Pb2O6 and Ag/AgI/Ag5Pb2O6. The voltage-current- characteristics of galvanostatic experiments up to 170°C reveal two different subsequent mechanisms during a deintercalation of one silver ion per formula unit (y = 1.0). First, a solid solution is formed, which is characterized by a steady increase of the measured voltage with decreasing silver content. The homogeneity range (x = 5.02(1) to 4.51(1)) for Ag xPb2O6 was determined by chemical analyses, coupled with Rietveld - refinements of X-ray powder diffraction data. The structural data indicate a topotactic removal predominantly of those silver ions located between the PbO3-sheets. The samples are diamagnetic. The resistivity decreases for y = 0.2 (ρ (0°C) = 1.3·10-3 Ωcm) and returns to values similar to that of the starting material (ρ (0°C) = 3.0·10-3 Ωcm for y = 0.5). For higher degrees of deintercalation up to y = 1.0 the cell voltage remains essentially constant, due to an equilibrium of the solid solution with a new compound of the composition Ag4Pb2O6. Although this substance can be synthesized as single phase, a structural characterization has not yet been possible. A complete charge / discharge cycle can be performed at room temperature and proofs reversibility. At higher temperatures (> 260°C) no solid solution regime occurred. Instead PbOx is formed, a fluorite related distorted defectstructure of PbO2. This compound can be obtained by complete removal of silver out of Ag5Pb2O 6. Thermogravimetric measurements suggest the composition Pb 2O3.33.
- Oberndorfer,Adelsberger,Jansen
-
-
Read Online
- Precipitation within Unilamellar Vesicles. Part 1. Studies of Silver(I) Oxide Formation
-
The precipitaion of small (ca. 10 nm) Ag2O crystallites within unilamellar vesicles has been studied by electron microscopy and light scattering.Many single-domain intravesicular crystallites have been observed by high-resolution imaging, indicating that crystallisation often initiates at a single site on the inner membrane surface followed by slow crystal growth.Under certain experimental conditions no nucleation has been observed below an extravesicular pH (pHout) of ca. 11.0 due to negligible diffusion of OH(1-) across the membrane.Above a pHout of 11.0 the rate of precipitaion has been found to be dependent on the rate of crystal growth.Semi-quantitative experiments have shown that the kinetics are first order with respect to intravesicular silver(I) concentration and first order with respect to extravesicular OH(1-) concentration between a pHout of 11.0 and 12.0.The general possibility of control of precipitaion by a vesicle membrane is discussed.
- Mann, Stephen,Williams, Robert J. P.
-
-
Read Online
- A new approach to Silverbismuthates
-
So far, Ag2BiO3, Ag3BiO3, Ag5BiO4, and Ag25Bi3O18 were only accessible through high pressure syntheses. A much more convenient synthesis route for these phases by reacting solid oxides in highly concentrated aequeous solutions of KOH is presented here. In each case single phased powders have been obtained, which were characterized by chemical analysis, x-ray diffraction and thermoanalysis.
- Oberndorfer,Jansen
-
-
Read Online
- Excited state properties of silver(I) nitrite complexes: Nitrogen conproportionation in Ag(NH3)NO2 induced by LLCT excitation
-
The complex Ag(NH3)NO2, which can be viewed as a ligand-based mixed-valence compound, undergoes a photoconproportionation of nitrogen from -III and +III to 0. It is suggested that this photolysis originates from a NH3 to NO2- LLCT state which is populated from a NO2- IL state. In this context, the excited state properties of AgNO2 and Ag(H2O)NO2 are also discussed.
- Kunkely, Horst,Vogler, Arnd
-
-
Read Online
- Two new one-dimensional luminescent silver(I) and lead(II) coordination polymers containing the flexible ligand 2-(1H-imidazole-1-yl)acetic acid
-
The free ligand, 2-(1H-imidazole-1-yl)acetate (Hima, 1), was crystallized from the mixture solution of 1. Two new coordination polymers, [Ag(Hima)(NO3)] (2) and {[Pb(Hima)2(NO3)](NO3)}n (3), are achie
- Wang, Yong-Tao,Qin, Ting-Xiao,Zhao, Chao,Tang, Gui-Mei,Li, Tian-Duo,Cui, Yue-Zhi,Li, Jun-Ying
-
-
Read Online
- A novel visible-light-driven photocatalyst Ag2O/AgI with highly enhanced photocatalytic performances
-
A series of heterojunction Ag2O/AgI photocatalysts with different Ag2O contents were successfully prepared though a facile two-step precipitation process at room temperature. The as-synthesized samples were measured in detail by XRD, EDS, XPS, SEM and DRS. The results showed that pherical Ag2O nanoparticles with diameter about 100–300?nm were uniformly distributed on the surface of AgI leading to the formation of Ag2O/AgI heterojunction. The photocatalytic activities of the obtained photocatalysts were evaluated by photocatalytic degradation of Rhodamine B (RhB) under visible light irradiation. The Ag2O/AgI with molar ratio of 1:1 showed the highest photocatalytic activities compared to the pure Ag2O and AgI with almost all RhB decomposed in 25?min. During photocatalytic process the visible light induced photogenerated electrons can be captured by Ag+ions on the surface lattice of heterojunction to form plasmonic Ag nanoparticles, which may promote the interfacial charge transfer. The enhanced photocatalytic activity was then largely attributed to the synergetic effects of heterojunction Ag2O/AgI/Ag and the efficient separation of photogenerated electron–hole pairs. This research may provide a novel Ag2O/AgI heterojunction with assistant of plasmonic Ag NPs to generate efficient, stable, and recyclable visible-light-driven plasmonic photocatalysts. The photocatalytic reaction kinetics and possible photocatalytic mechanism for this highly efficient photocatalysts were also proposed.
- Cui, Duo Heng,Zheng, Yi Fan,Song, Xu Chun
-
-
Read Online
- Synthesis, crystal structure determination, and physical properties of Ag5IO6
-
The silver iodate(VII), Ag5IO6, was obtained by reacting a stoichiometric mixture of Ag2O and KIO3, at elevated oxygen pressure, adding a small portion of distilled water. The synthesis was done at 673 K and 270 MPa of oxygen pressure. The crystal structure was solved by direct methods based on single crystal diffraction data (A3c, Z = 6, a = 5.9366(1), c = 32.1471(6) A, 323 independent reflections, R1 = 2.31%). According to conductivity measurements, Ag 5IO6 is semiconducting with a specific resistance of 0.08 Ωcm at 300 K. The activation energy was determined as 7.4(1) meV in the temperature range of 220-300 K, and 4.3(1) meV in the temperature range of 90-180 K. The optical band gap for Ag5IO6 is 1.4 eV. Ag5IO6 is diamagnetic with a magnetic susceptibility of -4.4×10-4 emu/mol.
- Kovalevskiy, Anton,Jansen, Martin
-
-
Read Online
- Enhancement of visible light photocatalytic activity of Ag2O/F-TiO2 composites
-
We synthesized the Ag2O/F-TiO2 composites via an aqueous precipitation method and characterized their morphology, structure and photocatalytic activity in the degradation of methylene blue (MB) using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-vis absorption spectroscopy, and electrochemical impedance spectra, respectively. The results show that the Ag2O addition could enhance the visible light photocatalytic activity of Ag2O/F-TiO2 composites with a maximum MB degradation rate of 93% for 60 min, much higher than that of the F-TiO2 (30%). The excellent photocatalytic activity is due to the increased visible light absorption, and promoted separation of photo-generated electrons and holes in F-TiO2 with the introduction of Ag2O.
- Yu, Wei,Liu, Xinjuan,Chu, Haipeng,Zhu, Guang,Li, Jinliang,Liu, Junying,Niu, Lengyuan,Sun, Zhuo,Pan, Likun
-
-
Read Online
- A silver(I) coordination polymer luminescent thermometer
-
A novel coordination polymer, namely, [Ag0.5(H2O)][Ag1.5(L)(H2O)]·2H2O (1) (H2L?=?4'-((2-carboxyphenoxy)methyl)biphenyl-2-carboxylic acid) has been successfully synthesized at room temperature. In compound 1, L anions bridge Ag(I) cations to form a one dimensional (1D) double chain structure, while there is an infinite Ag(I) chain joined by argentophilic interaction. Neighboring double chains are further extend into two dimensional (2D) supramolecular layers via intermolecular hydrogen-bonding interactions. Compound 1 has been characterized by infrared spectrum (IR), elemental analysis and powder X-ray diffraction (PXRD) analysis, and the luminescent properties of 1 were measured in detail. The luminescent intensity decreases regularly along with temperature increasing, which displays that compound 1 is a potential luminescent thermometer.
- He, Yuan-Chun,Xu, Na,Zheng, Xiaofeng,Yu, Yang,Ling, Baoping,You, Jinmao
-
-
Read Online
- Rapid synthesis of silver nanoparticles using the extract of Psidium guajava leaf based on light-emitting diodes irradiation
-
A green synthesis of silver nanoparticles (AgNPs) was conducted by using Psidium guajava (P. guajava) leaf extract under light-emitting diodes (LED) irradiation. The obtained AgNPs were characterized by ultraviolet–visible spectroscopy, X-ray diffraction , energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and transmission electron microscopy (TEM). In comparison to the absence of LED irradiation, the rate of AgNPs formation has been increased by more than twice with LED irradiation. Among LED irradiations, blue LED offered the most efficient in the formation of AgNPs. TEM analysis revealed that both AgNPs-N (without LED irradiation) and AgNPs-L (with LED irradiation) were nearly spherical with an average size of 32?nm.The antimicrobial assay indicated that AgNPs-L exhibited better antimicrobateria than AgNPs-N. The best antibacterial activity of AgNPs-L was recognized on L. fermentum (IC50 = 4.0?pM) for gram-negative bacteria, P. aeruginosa (IC50 = 3.5?pM) for gram-positive bacteria, and C. albicans (IC50 = 4.6?pM) for fungi.
- Nguyen, Trung Dien,Nguyen, Dam Phuc,Hoang, Yen Hai,Nguyen, Tuan Trong,Nguyen, Hong Thi
-
-
Read Online
- An iodide/anion exchange route to benzimidazolylidene silver complexes from benzimidazolium iodide: Crystal structures of N,N′-dibutylbenzimidazolylidene silver chloride, bromide, cyanide and nitrate
-
Syntheses of N,N′-dibutylbenzimidazolylidene silver complexes having chloride, nitrate or cyanide as an anion part through an iodide/anion exchange from N,N′-dibutylbenzimidazolium iodide are described, representing a practical route to benzimidazolylidene silver complexes from readily accessible benzimidazolium iodide. The crystal structures of N,N′-dibutylbenzimidazolylidene silver chloride, bromide, cyanide and nitrate have been determined, showing a close ligand-unsupported Ag-Ag interaction in [(NHC)2]Ag+[AgX2]- and a T shape geometry about the silver(I) cation in complexes of chloride, bromide and cyanide, but a nearly linear shape in the bis(N,N′-dibutylbenzimidazolylidene) silver complex [(NHC)2 Ag]+ NO3- with non-coordinating nitrate anion.
- Huang, Wen,Zhang, Ruixue,Zou, Gang,Tang, Jie,Sun, Jie
-
-
Read Online
- The mechanism and material aspects of a novel Ag2O/TiO2 photocatalyst active in infrared radiation for water splitting
-
The Ag2O/TiO2 catalyst produces hydrogen with water and water/methanol mixture upon irradiation with IR light. In this report, the material aspects and photocatalytic mechanism of an IR-active Ag2O/TiO2 photocatalyst for water splitting reaction were investigated. The Ag2O/TiO2 catalyst contained 28% silver and 72% titanium by w/w and the XPS and XRD results revealed the presence of Ag2O (Ag+), Ag0, TiO2 (Ti4+) and Ti3+ states in the Ag2O/TiO2 catalyst. A solid proof of the IR photon-initiated catalytic activity of the Ag2O/TiO2 catalyst was observed from the clear and enhanced IR response in the incident photon current conversion efficiency measurements of the Ag2O/TiO2 catalyst. Comparing the band gap energies to the energy of the IR source, plasmon-assisted photocatalytic activity and/or sub-band gap phonon-assisted multi-photon excitation mechanisms are proposed for the observed infrared photocatalytic activity of the Ag2O/TiO2 photocatalyst and the functions of Ag2O and TiO2 in dark photocatalysis are discussed.
- Gannoruwa,Ariyasinghe,Bandara
-
-
Read Online
- Solvation effect on the construction of coordination polymers containing a flexible four-pyridyl ligand. Synthesis and crystal structures of silver(I) complexes
-
Construction of AgX (X- = ClO4- and BF4-) with highly flexible N,N,N′,N′-tetrakis(ethylisonicotinoyl)ethylendiamine (L) has been scrutinized for the weak argentophilic, Ag anion, and Ag·solvent interactions. All such complexes afford coordination polymers consisting of 2:1 (Ag(I):L). [Ag2(L)(CH3CN)2](X)2 (X- = ClO4- and BF4-) and [Ag2(L)(H2O)](BF 4)2 are double-stranded 1D, whereas [Ag 2(ClO4)2(L)(Me2CO)2] yields a 2D network structure. The molecular construction has been affected by anions, solvents, and the crystallization method. The natures of anion- and solvent-coordination, including the argentophilic interaction play important roles in the formation of skeletal structures. For [Ag2(L)(CH 3CN)2](ClO4)2, weakly coordinated solvate acetonitrile reversibly associates and dissociates in the solid state.
- Lee, Sojung,Park, Kyung Hwan,Ahn, Jungmin,Lee, Young-A,Jung, Ok-Sang
-
-
Read Online
- Electrophilic Etherification of α-Heteroaryl Carbanions with Monoperoxyacetals as a Route to Ketene O, O- And N, O-Acetals
-
Alkyl ketene acetals are useful reactants in a variety of synthetic processes, and yet, there are limited routes to their formation as isolable products. We now report the successful synthesis and isolation of heteroaryl ketene acetals through intermolecular transfer of alkoxyl (δ+OR) from electrophilic peroxides to lithiated benzofurans, indoles, and pyridines. Primary and secondary peroxyacetals enable selective transfer of the nonanomeric alkoxy group in moderate to high yield; substrates bearing an electron-donating substituent show enhanced reactivity toward electrophilic oxygen. Heteroaryl ketene acetals are remarkably stable throughout traditional purification techniques; the superior stability of ketene N,O-acetals compared to ketene O,O-acetals is presumably due to increased aromaticity of the indole and pyridine structures. The presented method overcomes typical problems associated with alkyl ketene acetal synthesis as reported products withstood workup and flash column chromatography procedures.
- Paris, Timothy J.,Schwartz, Chris,Willand-Charnley, Rachel
-
p. 2369 - 2384
(2021/02/06)
-
- Oxidizing Cerium(IV) Alkoxide Complexes Supported by the Kl?ui Ligand [Co(η5-C5H5){P(O)(OEt)2}3]-: Synthesis, Structure, and Redox Reactivity
-
Tetravalent cerium alkoxide complexes supported by the Kl?ui tripodal ligand [Co(η5-C5H5){P(O)(OEt)2}3]- (LOEt-) have been synthesized, and their nucleophilic and redox reactivity have been studied. Treatment of the Ce(IV) oxo complex [CeIV(LOEt)2(O)(H2O)]·MeCONH2 (1) with iPrOH or reaction of [CeIV(LOEt)2Cl2] (2) with Ag2O in iPrOH afforded the Ce(IV) dialkoxide complex [CeIV(LOEt)2(OiPr)2] (3-iPr). The methoxide and ethoxide analogues [CeIV(LOEt)2(OR)2] (R = Me (3-Me), Et (3-Et)) have been prepared similarly from 2 and Ag2O in ROH. Reaction of 3-iPr with an equimolar amount of 2 yielded a new Ce(IV) complex that was formulated as the chloro-alkoxide complex [CeIV(LOEt)2(OiPr)Cl] (4). Treatment of 3-iPr with HX and methyl triflate (MeOTf) afforded [Ce(LOEt)2X2] (X- = Cl-, NO3-, PhO-) and [CeIV(LOEt)2(OTf)2], respectively, whereas treatment with excess CO2 in hexane led to isolation of the Ce(IV) carbonate [CeIV(LOEt)2(CO3)]. 3-iPr reacted with water in hexane to give a Ce(III) complex and a Ce(IV) species, presumably the reported tetranuclear oxo cluster [CeIV4(LOEt)4(O)5(OH)2]. The Ce(IV) alkoxide complexes are capable of oxidizing substituted phenols, possibly via a proton-coupled electron transfer pathway. Treatment of 3-iPr with ArOH afforded the Ce(III) aryloxide complexes [CeIII(LOEt)2(OAr)] (Ar = 2,4,6-tri-tert-butylphenyl (5), 2,6-diphenylphenyl (6)). On the other hand, a Ce(III) complex containing a monodeprotonated 2,2′-biphenol ligand, [CeIII(LOEt)2(tBu4C12H4O2H)] (7) (tBu4C12H4O2H2 = 4,4′,6,6′-tetra-tert-butyl-2,2′-biphenol), was isolated from the reaction of 3-iPr with 2,4-di-tert-butylphenol. The crystal structures of complexes 3-iPr, 3-Me, 3-Et, and 5-7 have been determined.
- Wong, Kai-Hong,Cheung, Wai-Man,Pham, Hoang-Long,So, Yat-Ming,Sung, Herman H.-Y.,Williams, Ian D.,Leung, Wa-Hung
-
p. 2261 - 2270
(2021/02/16)
-
- Silver-Mediated [3 + 2] Cycloaddition of Azomethine Ylides with Trifluoroacetimidoyl Chlorides for the Synthesis of 5-(Trifluoromethyl)imidazoles
-
A silver-mediated [3 + 2] cycloaddition of azomethine ylides with trifluoroacetimidoyl chlorides for the rapid assembly of 5-(trifluoromethyl)imidazoles has been developed. Notable features of the reaction include readily accessible reagents, a broad substrate scope, and high efficiency. The protocol can be successfully applied to construct the analogue of the specific allosteric modulator of GABAA receptors. The silver species could be recycled by a simple operation.
- Yang, Hefei,Lu, Shu-Ning,Chen, Zhengkai,Wu, Xiao-Feng
-
supporting information
p. 4361 - 4370
(2021/03/09)
-
- METAL-ORGANIC COORDINATION POLYMERS OF LANTHANIDES(III) WITH THIENOTHIOPHENDICARBOXYLATE LIGANDS
-
Abstract: Three novel metal-organic coordination polymers based on sulfur-containing thieno[3,2-b]thiophene-2,5-dicarboxylic (trans-H2ttdc) and thieno[2,3-b]thiophene-2,5-dicarboxylic (cis-H2ttdc) acids are obtained: [Ce2(
- Bolotov, V. A.,Demakov, P. A.,Dybtsev, D. N.,Fedin, V. P.,Samsonenko, D. G.,Samsonova, A. M.,Yudina, Yu. A.
-
p. 1599 - 1606
(2021/11/20)
-
- A gold(I) oxide double perovskite: Ba2AuIO6
-
Oxide perovskites offer improved stability compared to halide perovskite compounds for optoelectronic applications. Here, we report the first gold-containing double perovskite, Ba2AuIO6, and compare it to Ba2AgIO6 and Ba2NaIO6. Ba2AuIO6 and Ba2AgIO6 exhibit a monoclinic distortion from the cubic perovskite structure possessed by Ba2NaIO6 and have similar lattice constants despite the nominally larger size of Au+ compared to Ag+. Ba2AgIO6 shows photoluminescence (PL) at 2.10 eV, and Ba2AuIO6 exhibits PL at 1.30 and 1.47 eV. As prepared, both compounds appear stable under visible light at room temperature but decompose when subjected to gentle heating followed by illumination. Our data suggest that this behavior is due to the presence of -OH defects in the crystal structures. This discovery provides a new route to semiconductors with a near-IR band gap and identifies engineering challenges that must be addressed to use oxide perovskites for optoelectronic devices.
- Abraham, John B. S.,Bond, Jack,Drichko, Natalia,Imperato, Cassandra,Mcqueen, Tyrel M.,Pogue, Elizabeth A.
-
supporting information
p. 19033 - 19042
(2021/11/26)
-
- Chemical Modification of Surfaces and the Kinetics of Oxidation of Aqueous Salts of Silver Nanoparticles
-
Abstract: Hydrosols of silver nanoparticles chemically modified with cysteine and cysteamine are obtained. Their oxidation with solutions containing active oxygen and chlorine forms is studied. It is shown that the grafted layer of the modifier does not affect the oxidation of the metal core with sodium hypochlorite, but it does have a protective effect in the reaction with hydrogen peroxide. The orders of the reaction for the initial and chemically modified nanoparticles are 1 for sodium hypochlorite, and 0 for hydrogen peroxide. Chemically modified nanoparticles tend to form aggregates.
- Olenin, A. Yu.,Korotkov,Yagov,Lisichkin
-
p. 177 - 182
(2021/02/26)
-
- Biomimetic Oxidation of Monolignol Acetate and p-Coumarate by Silver Oxide in 1,4-Dioxane
-
Lignin acylated with acetate and/or p-coumarate is common in many herbaceous plants. Herein, the biomimetic oxidation of ?3-acylated monolignols with Ag2O was studied to understand the effect of ?3-acyl groups on monolignol polymerization. The oxidation of sinapyl acetate gave ?3-acylated and α-acylated β-O-4 dimers in 71 and 9.5% yields, respectively. The oxidation of sinapyl p-coumarate produced ?3-acylated β-O-4 and ?3-acylated tetralin β-β dimers in 53 and 16% yields, respectively. Only the sinapyl alcohol moiety in sinapyl p-coumarate reacted, and the p-coumarate moiety remained unchanged, suggesting that p-coumaric acid is not incorporated into the lignin backbone in the acylated lignins. All of the ?3-acylated monolignols used in this study produced the ?3-acylated β-O-4 dimers, which suggests that the ?3-acylated monolignols act as lignin monomers. The relatively high yields of the β-O-4 dimers indicate that Ag2O oxidation of the monolignols can be used as an easy method for synthesizing the β-O-4 dimer model compounds.
- Hamada, Masahiro,Kishimoto, Takao,Nakajima, Noriyuki,Urabe, Daisuke,Yamashita, Ayana
-
p. 2124 - 2131
(2020/03/06)
-
- Photocatalysis, photoinduced enhanced anti-bacterial functions and development of a selective: M-tolyl hydrazine sensor based on mixed Ag·NiMn2O4nanomaterials
-
In this work, a tri-metal based nanocomposite was synthesized and characterized. A detailed investigation of the photocatalytic dye degradation efficiency of the nanocomposite under visible light showed promising results in a wide pH range, both acidic and basic medium. Studies on anti-bacterial activity against seven pathogenic bacteria, including both Gram positive and Gram negative species, were conducted in the presence and absence of light and compared with the standard antibiotic gentamicin. The minimum inhibitory concentration (MIC) values of Ag·NiMn2O4 against multidrug-resistant (MDR) pathogens ranged from 0.008 to 0.65 μg μL-1, while the minimum bactericidal concentration (MBC) was found to be 0.0016 μg μL-1. The nanomaterial, Ag·NiMn2O4 was deposited onto the surface of a glassy carbon electrode (GCE; 0.0316 cm2) as a thin film to fabricate the chemical sensor probe. The proposed sensor showed linear current (vs. concentration) response to m-THyd (m-tolyl hydrazine) from 1.0 pM to 0.01 mM, which is denoted as the linear dynamic range (LDR). The estimated sensitivity and detection limit of the m-THyd sensor were found to be 47.275 μA μM-1 cm-2 and 0.97 ± 0.05 pM, respectively. As a potential sensor, it is reliable due to its good reproducibility, rapid response, higher sensitivity, working stability for long duration and efficiency in the analysis of real environmental samples.
- Al-Mamun, Mohammad,Alam, M. M.,Asiri, Abdullah M.,Azad, A. K.,Chandra Saha, Pallab,Hossain, Md Anwar,Rahman, Mohammed M.,Raihan, Topu,Rifat, Tanjila Parvin,Subhan, Md Abdus
-
p. 30603 - 30619
(2020/10/23)
-
- A flower-like ZnO-Ag2O nanocomposite for label and mediator free direct sensing of dinitrotoluene
-
2,4-Dinitrotoluene (2,4-DNT) is a nitro aromatic compound used as a raw material for trinitrotoluene (TNT) explosive synthesis along with several other industrial applications. Easy, rapid, cost-effective, and selective detection of 2,4-DNT is becoming essential due to its hepato carcinogenic nature and presence in surface as well as ground water as a contaminant. Keeping this in view, this research, for the first-time, reports the synthesis of novel ZnO-Ag2O composite nanoflowers on a gold (Au) substrate, to fabricate an electrochemical sensor for label-free, direct sensing of 2,4-DNT selectively. The proposed ZnO-Ag2O/Au sensor exhibits a sensitivity of 5 μA μM-1 cm-2 with a low limit of detection (LOD) of 13 nM, in a linear dynamic range (LDR) of 0.4 μM to 40 μM. The sensor showed reasonably high re-usability and reproducibility, with reliable results for laboratory and real-world samples.
- Adam, Jost,Bhanjana, Gaurav,Chakraborty, Urmila,Chaudhary, Ganga Ram,Kaur, Gurpreet,Kaushik, Ajeet,Mishra, Yogendra Kumar
-
supporting information
p. 27764 - 27774
(2020/08/17)
-
- Transition Metal Ions Regulated Structural and Catalytic Behaviors of Coordination Polymers
-
Three new coordination polymers (CPs), I [Cu(L)(H2O)]·2H2O, II [Zn(L)], and III [Ag(HL)(CH3CN)], were synthesized by employing a novel pyrazole-based dicarboxylate ligand (H2L) through a solvothermal strategy. Single-crystal structural analysis established that compounds I and II exhibit two-dimensional (2D) sheet structures, while compound III possesses a one-dimensional (1D) ladder structure due to the connectivity of terminal solvent moiety. The geometries of metal ions vary from square planar (Cu2+ ion) to distorted tetrahedral (Zn2+ and Ag+ ion). Topological study showed that compound I has made a (4·62)2(42·62·82) net, while compounds II and III have exposed common (44·62) SQL net and (42·6) net, respectively. The Lewis acidic nature of compounds I, II, and III has been confirmed with various heterogeneous catalytic reactions. For the first time, one-pot multicomponent synthesis of α-amino amidine has been performed by the three CPs and the reaction kinetics has been altered by the variation of Lewis acidic metal centers. The roles of metal ions for structural variations and the catalytic performances are investigated in a series of CPs.
- Kumar, Nikhil,Rom, Tanmay,Singh, Virender,Paul, Avijit Kumar
-
p. 5277 - 5288
(2020/09/09)
-
- Mpg-C3N4/Ag2O nanocomposites photocatalysts with enhanced visible-light photocatalytic performance
-
To study the photocatalytic activity under visible light irradiation, a series of mesoporous graphitic carbon nitride (mpg-C3N4)/Ag2O photocatalysts were synthesized. The as-prepared photocatalysts were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption Brunauer-Emmett-Teller method (N2-BET), Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectra (DRS), and photoluminescence spectra (PL) methods to determine their phase structure, purity, morphology, spectroscopic and photoluminescence emission performance, respectively. Photocatalytic degradation of methyl orange (MO) aqueous solution under visible-light irradiation indicated that the mpg-C3N4/Ag2O-50 nanocomposite exhibited the best activity. The degradation rate of MO reached to 90.8% in 120 min onto the mpg-C3N4/Ag2O-50 nanocomposite, and as compared with the pure mpg-C3N4 and Ag2O samples, the photocatalytic activity of the mpg-C3N4/Ag2O-50 nanocomposite was greatly enhanced. The enhancement of photocatalytic activity was mainly ascribed to the enhanced visible-light absorption ability and the formation of p-n heterojunctions between counterparts of the nanocomposites, which promoted the generation and separation of charge carriers.
- Jiang, Zhe,Le, Shukun,Xie, Yingjie,Qiuyan,Wang, Bin,Jiang, Tingshun
-
p. 721 - 728
(2018/12/14)
-
- New Ag8PtO6: Synthesis, crystal structure, physical properties and theoretical analyses
-
We report the synthesis, crystal structure, and basic physical properties of Ag8PtO6, which represents the first silver platinum ternary oxide. The crystalline compound was obtained from appropriate mixtures of the binary constituents under alkaline conditions at high oxygen pressure, while applying relatively mild thermal conditions (573 K). Ag8PtO6 crystallizes in a new crystal structure in the triclinic system (P1). The structure consists of slightly distorted, discrete PtO6 octahedra, which are linked via O-Ag-O dumbbells to form a three dimensional framework. It is a diamagnetic semiconductor with a band gap of 0.9 eV. DFT based calculations confirm an electronic ground state that corresponds to a 5d6 6s0 configuration of the Pt atoms, in accordance with the observed diamagnetism.
- Thakur, Gohil Singh,Reuter, Hans,Rosner, Helge,Fecher, Gerhard H.,Felser, Claudia,Jansen, Martin
-
p. 5058 - 5063
(2019/04/17)
-
- Boosting Electrochemical Reduction of CO2 at a Low Overpotential by Amorphous Ag-Bi-S-O Decorated Bi0 Nanocrystals
-
Bimetal-S-O composites have been rarely researched in electrochemical reduction of CO2. Now, an amorphous Ag-Bi-S-O decorated Bi0 catalyst derived from Ag0.95BiS0.75O3.1 nanorods by electrochemical pre-treatment was used for catalyzing eCO2RR, which exhibited a formate FE of 94.3 % with a formate partial current density of 12.52 mA cm?2 at an overpotential of only 450 mV. This superior performance was attributed to the attached amorphous Ag-Bi-S-O substance. S could be retained in the amorphous region after electrochemical pre-treatment only in samples derived from metal-S-O composites, and it would greatly enhance the formate selectivity by accelerating the dissociation of H2O. The existence of Ag would increase the current density, resulting in a higher local pH, which made the role of S in activating H2O more significantly and suppressed H2 evolution more effectively, thus endowing the catalyst with a higher formate FE at low overpotentials.
- Zhou, Jun-Hao,Yuan, Kun,Zhou, Liang,Guo, Yu,Luo, Ming-Yu,Guo, Xiao-Yan,Meng, Qing-Yuan,Zhang, Ya-Wen
-
supporting information
p. 14197 - 14201
(2019/09/03)
-
- TREATMENT WATER OF LIFESTYLE-RELATED DISEASES AND METHOD OF TREATING THE LIFESTYLE-RELATED DISEASES
-
To obtain a lifestyle-related disease therapeutic water which comprises a very small amount of anionized silver, nanosized gold, and 99.9% or more of water. A lifestyle-related disease therapeutic water comprising with respect to one liter of water (a), 3-15 mg in silver equivalent of thiosulfate silver ion (b), and 0.1-0.5 mg in gold equivalent of colloidal gold (c).
- -
-
Paragraph 0093; 0094
(2018/04/03)
-
- Pd(II)-Catalyzed Phosphorylation of Enamido C(sp2)–H Bonds: A General Route to β-Amido-vinylphosphonates
-
Organophosphorus compounds are essential structures in modern pharmaceutical, agrochemical, and material sciences. The development of new and efficient methods for the synthesis of C–P bonds has been an important focus of research. We herein report a Pd-catalyzed enamido C(sp2)–H phosphorylation for direct construction of C–P bonds under simple and convenient conditions without the need for additional ligands or directing groups. The present reaction can tolerate a wide range of functional groups, and furnish a variety of phosphorylation products including tetrasubstituted-vinyl β-aminophosphonates that are otherwise difficult to access. This protocol was also exemplified into the late-stage modification of bioactive natural products and was suitable for large-scale synthesis.
- Qiao, Baokun,Cao, Hao-Qiang,Huang, Yin-Jun,Zhang, Yue,Nie, Jing,Zhang, Fa-Guang,Ma, Jun-An
-
supporting information
p. 809 - 814
(2018/07/30)
-
- A set of Ag-based metal coordination polymers with sulfonate group: Syntheses, crystal structures and luminescent behaviors
-
In this paper, three Ag-based metal coordination polymers have been synthesized, namely, [Ag(BS)(BPP)2] (1), [Ag(MBS)(BPP)2] (2), and [Ag(ABS)(BPP)2]·H2O (3) (BS = benzenesulfonate, MBS = p-toluenesulfonate, ABS = p-aminophenyl sulfonate, BPP = 1,3-bis(pyridine-4-yl) propane). Metal coordination polymer 1–3 were structurally characterized by X-ray single-crystal diffraction, IR spectra, thermogravimetry analysis (TGA), and X-ray diffraction (PXRD). Through the X-ray single-crystal diffraction analyses, metal coordination polymers 1 and 2 exhibit one-dimensional structural motifs. Interestingly, metal coordination polymer 3 display the mixed one-dimensional and two-dimensional structures. Their thermogravimetric behaviors have been studied. Additionally, the luminescent properties of metal coordination polymers 1–3 were investigated in the solid-state at room temperature in details, which display the maximal emission peaks located at 388, 334 and 450 nm, respectively.
- Zhang, Xiao-Long,Tang, Gui-Mei,Wang, Yong-Tao
-
-
- Formation of hierarchically-ordered nanoporous silver foam and its electrocatalytic properties in reductive dehalogenation of organic compounds
-
Nanoporous silver foam on a glassy carbon electrode (AgNF/GC) was formed by cathodic deposition of silver from an acidic solution of AgBF4 at high current density. The material can be described (based on results of optical microscopy, SEM, TEM and XRD investigation) as hierarchically (micro/nano) porous matter with ca. 40 nm silver crystals assembled in irregular ca. 70-300 nm thick filaments arranged in a foam-like structure with ca. 20 μm cavities and ca. 7 μm walls. The AgNF surface area was estimated by pseudocapacitance measurement as ca. 12 times higher than the geometrical area. Reduction of bromobenzene and other aryl bromides containing redox-inactive (F-, CH3-, CH3O-) or redox-active (-NO2,-CN and CH3CO-) substituents, as well as alkyl bromides (CF3CHClBr, CF2Br2) on AgNF/GC was studied. The peak potentials of the processes assigned to debromination of the organic halides were less negative (up to +345 mV) than on smooth silver, indicating superior electrocatalytic properties of the nanoporous silver foam. Comparison of the CV peak currents of the processes on AgNF/GC and smooth silver, as well as their changes in cycling in different regimes allowed formation of a few kinds of electrocatalytically active sites on the AgNF surface to be suggested. Electrolysis of 1-bromo-4-fluorobenzene on the AgNF electrode led to fluorobenzene, and less than 1 mg of AgNF revealed performance comparable to 500 mg of smooth silver wire. The results can be utilized for creation of electrochemical sensors as well as for preparative detoxification of halogen-containing persistent organic pollutants.
- Mishura, Andrey M.,Lytvynenko, Anton S.,Gavrilenko, Konstantin S.,Baranchikov, Alexander E.,Grabovaya, Natalia V.,Kiskin, Mikhail A.,Kolotilov, Sergey V.
-
p. 17499 - 17512
(2018/11/01)
-
- Highly Efficient Selective Benzylation of Carbohydrates Catalyzed by Iron(III) with Silver Oxide and Bromide Anion as Co-catalysts
-
A highly efficient, green, and regioselective method for the benzylation of diols and polyols was developed. With the use of Ag2O (0.6 equiv.) and tetrabutylammonium bromide (0.1 equiv.) as co-catalysts, the iron(III)-catalyzed benzylation reaction proceeded to completion at 40 °C within 2–3 h and gave the products in high yields with high regioselectivities. A mechanism involving the principle of enhanced basicity of Ag2O by soft anions was proposed.
- Ren, Bo,Lv, Jian,Zhang, Yu,Tian, Jun,Dong, Hai
-
p. 950 - 953
(2017/03/27)
-
- Large-scale synthesis of polyhedral Ag nanoparticles for printed electronics
-
Printed electronics mainly use ink that contains silver with a high weight fraction to print conductive patterns. The synthesis of polyhedral Ag nanoparticles has been previously reported for lab-scale batches with a low weight fraction. The clean synthesis of large batches with homogeneous size and shape and high-volume fraction and conductivity is still challenging. Here, we report an original pathway to yield large batches of high weight fraction (typically 60 g of 50 wt% ink). The synthetic route goes through the formation of Ag2O, which is then reduced by H2O2 in the presence of a stabilizing polymer. The mechanism is discussed in view of the phase and composition analysis of the samples during the reaction. After printing lines of Ag NPs, the electrical properties of the Ag lines were measured, and the results are discussed along with the microstructure. The electrical resistivity reached values as low as 6.6 times the bulk value after mild annealing at 200 °C for 45 minutes.
- Polani, Shlomi,Melamed, Semyon,Burlaka, Luba,De La Vega, Fernando,Zitoun, David
-
p. 54326 - 54331
(2017/12/12)
-
- Novel high-efficiency visible-light responsive Ag4(GeO4) photocatalyst
-
A novel high-efficiency visible-light responsive Ag4(GeO4) photocatalyst was prepared by a facile hydrothermal method. The photocatalytic activity of as-prepared Ag4(GeO4) was evaluated by photodegradation of methylene blue (MB) dye and water splitting experiments. The photodegradation efficiency and oxygen production efficiency of Ag4(GeO4) were detected to be 2.9 and 1.9 times higher than those of Ag2O. UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence experiment and photoelectric effect experiments prove that the good light response and high carrier separation efficiency facilitated by the internal electric field are the main reasons for Ag4(GeO4)'s excellent catalytic activity. Radical-trapping experiments reveal that the photogenerated holes are the main active species. First-principles theoretical calculations provide more insight into understanding the photocatalytic mechanism of the Ag4(GeO4) catalyst.
- Zhu, Xianglin,Wang, Peng,Li, Mengmeng,Zhang, Qianqian,Rozhkova, Elena A.,Qin, Xiaoyan,Zhang, Xiaoyang,Dai, Ying,Wang, Zeyan,Huang, Baibiao
-
p. 2318 - 2324
(2017/07/22)
-
- Design and biological evaluation of some novel metal complexes derived from 1-(4-(imidazole-1-sulfonyl)phenyl)ethanone derivative
-
A monobasic bidentate ligand (H2L) was prepared from the reaction of cyanoacetic acid hydrazide with 1-(4-((1H-imidazol-2-yl)sulfonyl)phenyl)ethanone (ISE) in ethanol. A new series of Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Ag(I) and Zn(II) metal complexes of H2L ligand was synthesised. The interaction of the H2L ligand with salicyaldehyde and naphthaldehyde afforded coumarin and benzocoumarin derivatives, respectively. Structural characterisation of the newly synthesised compounds was achieved by elemental analysis, thermogravimetric analysis TGA, electrical molar conductance and spectral techniques, such as IR, UV, 1H NMR, 13C-NMR and ESR, as well as by magnetic moment measurements. The reported ligand (H2L) is monobasic dibasic with an N-O bidentate set, which coordinated with the metal ions to produce the metal complexes. The N atom of CH=N functioned coordinately with the O atom of carbonyl in the ligand. The prepared novel compounds were assessed for their antimicrobial activities. Fe(III), Co(II), Ni(II) and Ag(I) compounds showed good activity against Gram (-ve) bacteria. The newly synthesised compounds were assessed for their in vitro anticancer activity against both MCF-7 and HCT-116 cell lines; normal fibroblasts of the baby hamster kidney (BHK) cell line were also assessed. Ni(II) and Ag(I) complexes exhibited significant activity towards the MCF-7 and HCT-116 cell lines. Cu(II) and Fe(III) complexes exhibited better activity in the MCF-7 cell line, while Zn(II) and benzocoumarin compounds showed better activity in the HCT-116 cell line compared to doxorubicin (DOX) as a reference drug. Molecular docking was used to illustrate interaction among components within the active sites of dihydrofolate reductase (DHFR).
- Al-Harbi, Sami A.
-
p. 979 - 998
(2018/02/22)
-
- A novel methylation derivatization method for δ18O analysis of individual carbohydrates by gas chromatography/pyrolysis-isotope ratio mass spectrometry
-
Rationale The oxygen isotope ratio (δ18O) of carbohydrates derived from animals, plants, sediments, and soils provides important information about biochemical and physiological processes, past environmental conditions, and geographical origins, which are otherwise not available. Nowadays, δ18O analyses are often performed on carbohydrate bulk material, while compound-specific δ18O analyses remain challenging and methods for a wide range of individual carbohydrates are rare. Methods To improve the δ18O analysis of individual carbohydrates by gas chromatography/pyrolysis-isotope ratio mass spectrometry (GC/Pyr-IRMS) we developed a new methylation derivatization method. Carbohydrates were fully methylated within 24 h in an easy-to-handle one-pot reaction in acetonitrile, using silver oxide as proton acceptor, methyl iodide as methyl group carrier, and dimethyl sulfide as catalyst. Results The precision of the method ranged between 0.12 and 1.09‰ for the δ18O values of various individual carbohydrates of different classes (mono-, di-, and trisaccharides, alditols), with an accuracy of a similar order of magnitude, despite high variation in peak areas. Based on the δ18O values of the main isomers, important monosaccharides such as glucose and fructose could also be precisely analyzed for the first time. We tested the method on standard mixtures, honey samples, and leaf carbohydrates extracted from Pinus sylvestris, showing that the method is also applicable to different carbohydrate mixtures. Conclusions The new methylation method shows unrivalled accuracy and precision for δ18O analysis of various individual carbohydrates; it is fast and easy-to-handle, and may therefore find wide-spread application.
- Lehmann, Marco M.,Fischer, Maria,Blees, Jan,Zech, Michael,Siegwolf, Rolf T. W.,Saurer, Matthias
-
p. 221 - 229
(2016/01/09)
-
- Complexes of {Mo6I8} with nitrophenolates: Synthesis and luminescence
-
New bright-red luminescent nitrophenolate complexes (Bu4N)2[{Mo6I8}(OR)6] (R = C6H4-p-(NO2) (1), C6H3-2,4-(NO2)2 (2)) have been prepared from (Bu4N)2[{Mo6I8}I6] and AgOR, characterized by X-ray analysis, UV-Vis and IR spectroscopies and ESI-mass spectrometry. Both complexes are stable in solutions, and show multiple quasi-reversible reduction waves at highly negative potentials in CV studies. Complex 2 shows a quasi reversible oxidation at E1/2 = 1.41 V (vs. Ag/AgCl). Both 1 and 2 are intensely coloured with very high molar absorption coefficients in the near-ultraviolet region, 143 380 and 151 050 l mol-1 cm-1 for 1 and 2, respectively. Similar to other [{Mo6I8}L6]2- clusters 1 and 2 upon UV photoexcitation display relatively narrow red emission.
- Mikhailov, Maksim A.,Brylev, Konstantin A.,Virovets, Alexandr V.,Gallyamov, Marsel R.,Novozhilov, Igor,Sokolov, Maxim N.
-
p. 1162 - 1168
(2016/02/19)
-
- Synthesis, characterizations of superparamagnetic Fe3O4-Ag hybrid nanoparticles and their application for highly effective bacteria inactivation
-
In recent years, outbreaks of infectious diseases caused by pathogenic micro-organisms pose a serious threat to public health. In this work, Fe3O4-Ag hybrid nanoparticles were synthesized by simple chemistry method and these prepared nanoparticles were used to investigate their antibacterial properties and mechanism against methicilline-resistant Staphylococcus aureus (MRSA) pathogen. The formation of dimer-like nanostructure of Fe3O4-Ag hybrid NPs was confirmed by X-ray diffraction and High-resolution Transmission Electron Microscopy. Our biological analysis revealed that the Fe3O4-Ag hybrid NPs showed more noticeable bactericidal activity than that of plain Fe3O4 NPs and Ag-NPs. We suggest that the enhancement in bactericidal activity of Fe3O4-Ag hybrid NPs might be likely from main factors such as: (i) enhanced surface area property of hybrid nanoparticles; (ii) the high catalytic activity of Ag-NPs with good dispersion and aggregation stability due to the iron oxide magnetic carrier, and (iii) large direct physical contacts between the bacterial cell membrane and the hybrid nanoparticles. The superparamagnetic hybrid nanoparticles of iron oxide magnetic nanoparticles decorated with silver nanoparticles can be a potential candidate to effectively treat infectious MRSA pathogen with recyclable capability, targeted bactericidal delivery and minimum release into environment.
- Tung, Le Minh,Cong, Nguyen Xuan,Huy, Le Thanh,Lan, Nguyen Thi,Phan, Vu Ngoc,Hoa, Nguyen Quang,Vinh, Le Khanh,Thinh, Nguyen Viet,Tai, Le Thanh,Ngo, Duc-The,M?lhave, Kristian,Huy, Tran Quang,Le, Anh-Tuan
-
p. 5902 - 5912
(2016/07/06)
-
- Synthesis of silver nanoparticles-decorated FePO4 nanosphere at a gas-liquid interface for the electrochemical detection of Hydrogen peroxide
-
Silver nanoparticles were prepared by chemical reduction of acetaldehyde gas in the absence of protective gas, and Ag/FePO4 nanocomposites were synthesised by modified silver mirror reaction at a gas-liquid interface. A hydrogen peroxide (H2O2) electrochemical sensor was constructed through immobilizing Ag/FePO4 nanocomposites on gold (Au) electrode. The morphology and composition of the nanocomposites were characterized by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). The electrochemical investigations of the sensor indicated that it exhibited excellent analytical performance with a wide linear range from 3.0×10?5 to 1.1×10?2 mol?L?1 and a low detection limit of 4.7 μmol?L?1 at a signal-to-noise ratio of 3. Meanwhile, it also showed acceptable reproducibility and anti-interference ability. This study may provide a new method for the synthesis of highly dispersed metal nanoparticles which might be used in other related fields. [Figure not available: see fulltext.]
- RAO,ZHANG,ZHENG
-
p. 839 - 847
(2016/05/19)
-
- Synthesis of Ag nanoparticles on oxide and carbon supports from Ag diammine precursor
-
To determine whether the method of “strong electrostatic adsorption” (SEA) can be extended to the preparation of uniform and highly dispersed supported Ag catalysts, the adsorption of silver diammine, Ag(NH3)2+, also known as Tollen's reagent, has been examined over five supports (i.e., SiO2, γ-Al2O3, ZrO2, Nb2O5, and carbon) with different surface areas and PZCs. The speciation of Ag in solution was followed by UV–vis spectroscopy, Ag uptake as a function of the solution pH was determined by atomic absorption, and Ag particle size was determined by powder XRD and STEM. At the Ag concentrations, pH, and surface loadings employed, silver diammine complexes convert into soluble Ag(H2O)2+ aquo complexes below pH 11 and hydrolyze to insoluble Ag2O above pH 11. The deposition of either Ag species over carbon at any pH appears to be reactive and results in large particles. The silver aquo complexes appear to adsorb via ion exchange near the PZC of alumina, zirconia, and niobia but not silica, while the silver diammine complexes appear to adsorb electrostatically at high pH over all the oxides tested - niobia, silica, zirconia, and alumina in the order of ascending PZC. Niobia, which has the lowest PZC, adsorbs the highest surface density of Ag via both mechanisms. The particles obtained via electrostatic adsorption of Ag(NH3)2+ at high pH are somewhat smaller than those formed from Ag(H2O)2+ ions at the lower pH values. In the absence of ammonia in solution at high pH, deposition of Ag aquo complexes occurs via surface precipitation and gives large particles. In sum, SEA of silver ammine is demonstrated to be a simple, reproducible way to synthesize small particles on all supports but carbon.
- Kyriakidou, Eleni A.,Alexeev, Oleg S.,Wong, Andrew P.,Papadimitriou, Christina,Amiridis, Michael D.,Regalbuto, John R.
-
p. 749 - 756
(2016/12/09)
-
- Cobalt(II)/silver(I) coordination polymers with bis(2-methylbenzimidazole) and polycarboxylate ligands
-
Three coordination polymers, [Co(L)(tbta)]n (1), [Ag(L)(H2O)·(Hhpht)]n (2) and [Ag2(L)1.5(oba)]n (3) (L?=?1,4-bis(2-methylbenzimidazol-1-ylmethyl)benzene, H2tbta?=?tetrabromoterephthalic acid, H2hpht?=?homophthalic acid, H2oba?=?4,4′-oxybis(benzoic acid)), have been hydrothermally synthesized and structurally characterized. Complex 1 displays a 2-D uninodal 4-connected sql network, 2 and 3 feature chain structures, which further generate 2D supramolecular networks through hydrogen bonding interactions. The thermal and fluorescence properties of 1–3 have been carried out and discussed.
- Zhang, Xu,Liu, Yong Guang,Hao, Zeng Chuan,Cui, Guang Hua
-
p. 1514 - 1524
(2016/07/06)
-
- Synthesis, crystal structures and photocatalytic properties of four silver(I) coordination polymers based on semirigid bis(pyrazole) and carboxylic acid co-ligands
-
Four Ag(I) coordination polymers, formulated as [Ag(L1)(tpa)0.5]n (1), {[Ag(L2)(ndc)0.5]·0.5H2ndc}n (2), [Ag(L3)0.5(ndc)0.5]n (3) and {[Ag(L3)]·H3bptc}n (4) (L1?=?4,4′-bis(pyrazole-1-ylmethyl)-biphenyl, L2?=?4,4′-bis(3,5-dimethylpyrazol-1-ylmethyl)-biphenyl, L3?=?1,4-bis(3,5-dimethylpyrazol-1-ylmethyl)benzene, H2tpa?=?terephthalic acid, H2ndc?=?2,6-naphthalenedicarboxylic acid, H4bptc?=?3,3′,4,4′-biphenyltetracarboxylic acid), have been hydrothermally synthesized and structurally characterized. Complex 1 features the rare binodal (4,4)-connected 2D 4,4L10 topological network with a point symbol of {32·4.62·7}2{32·62·72}. Complex 2 has a folded ladder-like chain structure, which is further extended into a 3D supramolecular network via O–H···O hydrogen bonding and π···π stacking interactions. Complexes 3 and 4 both possess 1D zigzag chain structures. Complex 3 is further extended into a binodal (3,4)-connected network with the point symbol of {4.84·10}{62·82}2 by Ag···O weak interactions, while complex 4 is further connected through O–H···O hydrogen bonding and π···π interactions to afford a 2D supramolecular structure. The photoluminescence spectra and photocatalytic properties of these complexes for degradation of methylene blue and methyl orange are reported.
- Huan, Dian-Heng,Zhao, Yan-Qin,Dong, Gui-Ying,Yin, Fu-Jun,Wang, Sheng-Chun
-
p. 701 - 712
(2016/07/29)
-
- One-step synthesis of amorphous silver silicates with tunable light absorption spectra and photocatalytic activities in the visible region
-
A series of amorphous silver silicates with different compositions were synthesized for the first time by one-step co-precipitation. Silicate ions were found to have important role on determining visible light absorption and photocatalytic activities of amorphous silver silicates, and the sample with Ag/Si ratio of 3.20 exhibits optimal photocatalytic activity. Amorphous and active: A series of amorphous silver silicates with different compositions were synthesized for the first time by one-step co-precipitation. Silicate ions were found to have an important role for determining visible light absorption and photocatalytic activities of the silver silicates.
- Lou, Zaizhu,Wang, Zeyan,Huang, Baibiao,Dai, Ying,Wang, Gang,Jiang, Zaiyong,Zhang, Xiaoyang,Qin, Xiaoyan,Li, Yanqing
-
p. 8706 - 8710
(2015/06/08)
-
- METHOD FOR PRODUCING SILVER LACTATE
-
The present invention relates to a method for preparing a lactic acid (CH_3CH(OH)COOAg), the method comprising: a first process of obtaining silver oxide (Ag_2O) by mixing and reacting silver nitrate (AgNO_3) and sodium hydroxide (NaOH); and a second process of obtaining lactic acid (CH_3CH(OH)COOAg) by adding and reacting lactic acid to silver oxide obtained in the first process wherein it is possible to obtain lactic acid at a high yield by adding and reacting 10 to 30% greater amount of sodium hydroxide than 1 equivalent of lactic acid.COPYRIGHT KIPO 2015
- -
-
Paragraph 0023; 0037-0039
(2016/12/26)
-
- Carboxy derivatised Ir(iii) complexes: synthesis, electrochemistry, photophysical properties and photocatalytic hydrogen generation
-
In this contribution the synthesis and characterisation of a series of novel mixed ligand iridium(iii) complexes, functionalised with a carboxy ester or phosphonate groups are reported. These groupings are introduced on the 4-position of either the phenyl pyridine or the 2,2′-bipyridyl ligands. A low temperature high yield synthesis for the precursor [Ir(ppy-COOEt)2(μ-Cl)]2 was developed. The photophysical and electrochemical properties of these compounds are also described, together with their behaviour as photosensitisers for the generation of hydrogen from water.
- Paul, Avishek,Das, Nivedita,Halpin, Yvonne,Vos, Johannes G.,Pryce, Mary T.
-
p. 10423 - 10430
(2015/06/08)
-
- Mechanism of the catalytic synthesis of water on silver
-
A mechanism of the macroscopic step of water synthesis in the oxidation of hydrogen on silver has been revealed.
- Dokuchits, Eugene V.,Khasin, Alexander V.,Khassin, Alexander A.
-
p. 155 - 156
(2015/04/14)
-
- Enhanced basicity of Ag2O by coordination to soft anions
-
In Ag2O-mediated benzylation, the addition of a catalytic amount of KI can greatly improve reactivity. This is usually attributed to the formation of a more reactive iodo-substituted electrophile. However, our studies show this to be due to the enhanced basicity of Ag2O through coordination of soft iodide anions to the silver atom, and show KI to be an initiator. A catalytic amount of Ag2O and NaBr can catalyze transesterification reactions, indicating the enhanced basicity of Ag2O by bromide. We believe that this is a general effect for metal oxides and soft anions, applicable to a wider range of organic reaction systems. All your base belongs to us: In Ag2O-mediated benzylation, the addition of a catalytic amount of KI can greatly improve reactivity. Our studies show this to be attributable to the enhanced basicity of Ag2O through coordination of soft iodide anions to the silver atom, and show KI to be an initiator. Thus, NaBr as an initiator combined with Ag2O has been successfully used to catalyze transesterification reactions.
- Ren, Bo,Wang, Meiyan,Liu, Jingyao,Ge, Jiantao,Dong, Hai
-
p. 761 - 765
(2015/03/04)
-
- Improved shape memory performance of star-shaped POSS-polylactide based polyurethanes (POSS-PLAUs)
-
Star-shaped polyhedral oligomeric silsesquioxane multi-arm polylactides (POSS-PLA) with various arm lengths were synthesized by ring opening polymerization of d,l-lactide. Then, the star-shaped POSS-PLA based polyurethanes (POSS-PLAUs) were synthesized by cross-linking POSS-PLAs with various PLA arm lengths and polytetramethylene ether (PTMEG) with hexamethylene diisocyanate (HDI). Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) were utilized to characterize the structures of the materials. Differential scanning calorimetry (DSC) experiments were carried out to investigate the glass transition temperature (Tg) of POSS-PLAUs and crystallinity of PTMEG. Dynamic mechanical analysis (DMA) and stress relaxation experiments were used to study the dynamic mechanical properties and stress relaxation behaviors of POSS-PLAUs. Cyclic thermal mechanical and physical shape recovery tests were used to study the shape memory properties. The effects of POSS and PLA arm length on the mechanical, thermal properties and the shape memory behaviors were investigated. In our system, PLA arm length has no significant effect on glass transition temperature (Tg). Tg increases with the POSS content in the networks due to the obstructed movement of the polymer chains caused by caged POSS. E′ increases from POSS-PLAU110 to POSS-PLAU530 due to the decreasing of PTMEG content. Dynamic mechanical analysis reveals a similar relationship of glass transition temperature to POSS content. The stress relaxation curves show an increase in initial stress in POSS-PLAUs with longer arm length due to lower PTMEG content. The relaxation ratio is higher for the polymer with shorter PLA arm length. The quick relaxation above the triggering temperature of POSS-PLAU with shorter PLA arm length is favorable for quick shape recovery. All the POSS-PLAUs have excellent shape memory properties with high shape fixity ratios above 99%, shape recovery ratios around 84% for the first cycle and above 89% for the second cycle. POSS-PLAUs with the shorter arm length show faster recovery speed due to the higher content of POSS cores.
- Gu,Gao
-
p. 90209 - 90216
(2015/11/10)
-
- Synthesis, crystal structures, luminescence and catalytic properties of two d10 metal coordination polymers constructed from mixed ligands
-
Two new coordination polymers [Cd(bmb)(hmph)]n (1), {[Ag(bmb)]·H2btc}n (2) (bmb = 1,4-bis(2-methylbenzimidazol-1-ylmethyl)benzene, H2hmph = homophthalic acid, H3btc = 1,3,5-benzenetetracarboxylic acid) were synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction methods, IR spectroscopy, TGA, XRPD and elemental analysis. Complex 1 features a 3D threefold interpenetrating dia array with a 4-connected 66 topology. Complex 2 shows a 1D helix chain structure connected by L1 ligands, which is finally extended into a rarely 2D 4L2 supramolecular network via C-H-O hydrogen bond interactions. In addition, the luminescence and catalytic properties of the two complexes for the degradation of the methyl orange azo dye in a Fenton-like process were presented. The degradation efficiency of the methyl orange azo dye for 1 and 2 are 56% and 96%, respectively.
- Wang, Xiao-Xiao,Zhang, Ming-Xi,Yu, Baoyi,Van Hecke, Kristof,Cui, Guang-Hua
-
p. 442 - 448
(2015/01/30)
-
