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1.
ACS Appl Mater Interfaces ; 16(36): 47137-47149, 2024 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-39106079

RESUMEN

With their low immunogenicity and excellent deliverability, extracellular vesicles (EVs) are promising platforms for drug delivery systems. In this study, hydrophobic molecule loading techniques were developed via an exchange reaction based on supramolecular chemistry without using organic solvents that can induce EV disruption and harmful side effects. To demonstrate the availability of an exchanging reaction to prepare drug-loading EVs, hydrophobic boron cluster carborane (CB) was introduced to EVs (CB@EVs), which is expected as a boron agent for boron neutron capture therapy (BNCT). The exchange reaction enabled the encapsulation of CB to EVs without disrupting their structure and forming aggregates. Single-particle analysis revealed that an exchanging reaction can uniformly introduce cargo molecules to EVs, which is advantageous in formulating pharmaceuticals. The performance of CB@EVs as boron agents for BNCT was demonstrated in vitro and in vivo. Compared to L-BPA, a clinically available boron agent, and CB delivered with liposomes, CB@EV systems exhibited the highest BNCT activity in vitro due to their excellent deliverability of cargo molecules via an endocytosis-independent pathway. The system can deeply penetrate 3D cultured spheroids even in the presence of extracellular matrices. The EV-based system could efficiently accumulate in tumor tissues in tumor xenograft model mice with high selectivity, mainly via the enhanced permeation and retention effect, and the deliverability of cargo molecules to tumor tissues in vivo enhanced the therapeutic benefits of BNCT compared to the L-BPA/fructose complex. All of the features of EVs are also advantageous in establishing anticancer agent delivery platforms.


Asunto(s)
Terapia por Captura de Neutrón de Boro , Vesículas Extracelulares , Terapia por Captura de Neutrón de Boro/métodos , Animales , Vesículas Extracelulares/química , Vesículas Extracelulares/metabolismo , Ratones , Humanos , Boranos/química , Boro/química , Compuestos de Boro/química , Compuestos de Boro/farmacología , Línea Celular Tumoral , Portadores de Fármacos/química , Ratones Desnudos , Ratones Endogámicos BALB C
2.
Inorg Chem ; 63(22): 10207-10220, 2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38767574

RESUMEN

We prepared polyoxomolybdates with methylammonium countercations from methylammonium monomolybdate, (CH3NH3)2[MoO4], through two dehydrative condensation methods, acidifying in the aqueous solution and solid-state heating. Discrete (CH3NH3)10[Mo36O112(OH)2(H2O)14], polymeric ((CH3NH3)8[Mo36O112(H2O)14])n, and polymeric ((CH3NH3)4[γ-Mo8O26])n were selectively isolated via pH control of the aqueous (CH3NH3)2[MoO4] solution. The H2SO4-acidified solution of pH < 1 produced "sulfonated α-MoO3", polymeric ((CH3NH3)2[(MoO3)3(SO4)])n. The solid-state heating of (CH3NH3)2[MoO4] in air released methylamine and water to produce several methylammonium polyoxomolybdates in the sequence of discrete (CH3NH3)8[Mo7O24-MoO4], discrete (CH3NH3)6[Mo7O24], discrete (CH3NH3)8[Mo10O34], and polymeric ((CH3NH3)4[γ-Mo8O26])n, before their transformation into molybdenum oxides such as hexagonal-MoO3 and α-MoO3. Notably, some of their polyoxomolybdate structures were different from polyoxomolybdates produced from ammonium molybdates, such as (NH4)2[MoO4] or (NH4)6[Mo7O24], indicating that countercation affected the polyoxomolybdate structure. Moreover, among the tested polyoxomolybdates, (CH3NH3)6[Mo7O24] was the best negative staining reagent for the observation of the SARS-CoV-2 virus using transmission electron microscopy.

3.
Inorg Chem ; 63(12): 5672-5680, 2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38468598

RESUMEN

Organometallic-polyoxometalate (POM) complexes form a unique class of molecular organometallic oxides characterized by the dynamic behavior of the organometallic cations. Herein, we investigated the reactivity of Cp*Ir-octatungstate clusters (where Cp* represents pentamethylcyclopentadienyl, C5Me5-) with Werner-type transition-metal aquo cations. The addition of Ag+, Co2+, Ni2+, and M3+ (M = Cr, Fe, or In) cations to the aqueous solution of Cp*Ir-octatungstate clusters resulted in the formation of [{Ag(OH2)2}2{Cp*Ir(OH2)}2{Cp*IrW3O12(OH)}2(WO2)2] (1), Co1.5K0.8Na0.2[{trans-Co(OH2)2}{Cp*IrW3O12(OH)}2(WO2)1.3{cis-Co(OH2)2}0.7] (2-Co), Ni0.2K1.4Na0.2[{Ni(OH2)4}2{Cp*IrW3O12(OH)}2(WO2)1.1{cis-Ni(OH2)2}0.9] (2-Ni), and [{M(OH2)4}2{Cp*IrW3O12(OH)}2{cis-M(OH2)2}2](NO3)2 (M = Cr, 3-Cr; Fe, 3-Fe; or In, 3-In), respectively. All clusters share the same cubane-type {Cp*IrW3O12(OH)}5- building block, representing the first examples of organoiridium-POMs functionalized by transition-metal aquo cations. These compounds are insoluble in water, facilitating the evaluation of their heterogeneous water-oxidation properties. Notably, 2-Co generates the highest catalytic water oxidation current. This work provides a new synthetic method to introduce metal-aquo complexes on an organometallic oxide cluster, producing multimetallic molecules that model the catalytic sites of complex oxides.

4.
Dalton Trans ; 52(48): 18168-18176, 2023 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-37971057

RESUMEN

The potassium and proton mixed salt of mono-Nb substituted Keggin-type phosphomolybdate, KH3[PMo11NbO40], was isolated in a pure form by reacting Keggin-type phosphomolybdic acid (H3[PMo12O40]) and potassium hexaniobate (K8Nb6O19) in water, followed by freeze-drying. The all protonic form, H4[PMo11NbO40], was isolated via proton exchange with H-resin and subsequent freeze-drying. The most crucial factor to isolate KH3[PMo11NbO40] and H4[PMo11NbO40] in pure forms is the evaporation of water using the freeze-drying method. Using a similar procedure, the potassium salt of the di-Nb substituted compound K5[PMo10Nb2O40] was isolated. H4[PMo11NbO40] exhibited high catalytic activity for oxidizing isobutylaldehyde to methacrolein and moderate catalytic activity for the Wacker-type oxidation of allyl phenyl ether when combined with Pd(OAc)2.

5.
Angew Chem Int Ed Engl ; 62(41): e202309469, 2023 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-37475570

RESUMEN

Precise structural design of large hetero-multinuclear metal-oxo clusters is crucial for controlling their large spin ground states and multielectron redox properties for application as a single-molecule magnet (SMM), molecular magnetic refrigeration, and efficient redox catalyst. However, it is difficult to synthesize large hetero-multinuclear metal oxo clusters as designed because the final structures are unpredictable when employing conventional one-step condensation reaction of metal cations and ligands. Herein, we report a "cationic metal glue strategy" for increasing the size and nuclearity of hetero-multinuclear metal-oxo clusters by using lacunary-type anionic molecular metal oxides (polyoxometalates, POMs) as rigid multidentate ligands. The employed method enabled the synthesis of {(FeMn4 )Mn2 Ln2 (FeMn4 )} oxo clusters (Ln=Gd, Tb, Dy, and Lu), which are the largest among previously reported paramagnetic hetero-multinuclear metal-oxo clusters in POMs and showed unique SMM properties. These clusters were synthesized by conjugating {FeMn4 } oxo clusters with Mn and Ln cations as glues in a predictable way, indicating that the "cationic metal glue strategy" would be a powerful tool to construct desired large hetero-multinuclear metal clusters precisely and effectively.

6.
Chemistry ; 29(45): e202301051, 2023 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-37249241

RESUMEN

We report the first single-crystal X-ray structural evidence of the potassium salt of the hexalacunary [α-H2 P2 W12 O48 ]12- (abbreviated as {P2 W12 }) anion after its discovery by Contant and Ciabrini in 1977. In addition, we observed oligomerization of {P2 W12 } into a {WO(OH2 )}4+ -bridged Pacman-shaped [{WO(OH2 )}(α-HP2 W12 O48 )2 ]22- ({P4 W25 }) dimer and a cyclic [{WO(OH2 )}3 (P2 W12 O48 )3 ]30- ({P6 W39 }) trimer. The three phosphotungstate anions were synthesized through recrystallization of (NH4 )12 [α-H2 P2 W12 O48 ] from slightly alkaline (HOCH2 )3 CNH2 /KCl, CH3 NH3 Cl/KCl, and CH3 NH3 Cl/NH4 Cl solutions. The structure of {P2 W12 } is derived from [α-P2 W18 O62 ]6- that has six tungsten atoms one from each polar group and four from the belt-removed, and the center of the lacunary site is capped by a potassium cation. Structures of {P4 W25 } and {P6 W39 } are constructed by connecting two and three {P2 W12 } units with {WO(OH2 )}4+ , respectively. The isolation of a pure {P6 W39 } phosphotungstate framework without coordination with transition metal cations is unprecedented. Powder X-ray diffraction confirmed the bulk purity of these compounds, indicating that selective crystallization was achieved through the selection of countercations and pH.

7.
Inorg Chem ; 62(17): 6759-6767, 2023 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-37068202

RESUMEN

We scrutinized the speciation of Cp*Ir-containing tungsten oxide clusters (Cp* is pentamethylcyclopentadienyl anion) in aqueous mixtures of [(Cp*IrCl)2(µ-Cl)2] and Na2WO4 in varying molar ratios. 1H nuclear magnetic resonance (NMR) spectroscopy revealed the formation of three distinct Cp*Ir-polyoxotungstate species in the reaction solution, and they were isolated as Na4[(Cp*Ir)2(µ-OH)3]2[(Cp*Ir)2H2W8O30] (1), [(Cp*Ir)2(µ-OH)3]2[(Cp*Ir)2{Cp*Ir(OH2)}2H2W8O30] (2), and [(Cp*Ir)2{Cp*Ir(OH2)}2{Cp*Ir(OH2)2}2H2W8O30](NO3)2 (3) from the mixtures in which iridium concentration is less than, equal to, and more than the tungsten concentration, respectively. These results show the octatungstate [H2W8O30]10- anion is the major polyoxotungstate species in the presence of {Cp*Ir}2+ cations, and it has high nucleophilicity enough to bind up to six {Cp*Ir}2+ cations on its surfaces producing a cationic Cp*Ir-octatungstate complex. The octatungstate anion was also generated from the reaction of [(Cp*IrCl)2(µ-Cl)2] and methylammonium paratungstate-B, (CH3NH3)10[H2W12O42], and was isolated as a methylamine-coordinated complex (CH3NH3)2[(Cp*Ir)2{Cp*Ir(NH2CH3)}2H2W8O30] (4), indicating {Cp*Ir}2+ cations function as a structure-directing agent that converts tungsten species into octatungstate anions in aqueous solution. In addition, the coordination environment of {Cp*Ir}2+ can be further modified by coordination with pyridine forming [{Cp*Ir(NC5H5)}2(µ-OH)2][(Cp*Ir)2{Cp*Ir(NC5H5)}2H2W8O30] (5).

8.
Eur J Inorg Chem ; 2022(26): e202200322, 2022 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-35942204

RESUMEN

The solid-state thermal structure transformation of methylammonium vanadate, (CH3NH3)VO3, from -150 °C to 350 °C is reported. Variable-temperature X-ray single-crystal structure analysis at 23, 0, -50, -100, and -150 °C reveal (CH3NH3)VO3 comprises of methylammonium cations and "snake-like" ([VO3]-)n anion chains propagating along the c-direction in the Pna21 space group. In between -150 and -100 °C, we observe a reversible structural transformation due to the re-orientation of the methylammonium cations in the crystal packing, which is also confirmed by the reversible profiles observed in differential scanning calorimetry. The methylammonium vanadate is stable until at ca. 100 °C and further heating releases methylamine and water and V2O5 is formed at ca. 275 °C . Furthermore, we show that the methylammonium vanadate can be used as a negative staining reagent for visualizing SARS-CoV-2, allowing us to discern the spike proteins from the body of the virus using transmission electron microscopy.

9.
Chemistry ; 28(41): e202200618, 2022 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-35581526

RESUMEN

Zeolitic octahedral metal oxides are inorganic crystalline microporous materials with adsorption and redox properties. New ϵ-Keggin nickel molybdate-based zeolitic octahedral metal oxides have been synthesized. 31 P NMR spectroscopy shows that reduction of MoVI -based molybdates forms an ϵ-Keggin polyoxometalate that immediately transfers to the solid phase. Investigation of the formation process indicates that a low Ni concentration, insoluble reducing agent, and long synthesis time are the critical factors for obtaining the zeolite octahedral metal oxides rather than the ϵ-Keggin polyoxometalate molecule. The synthesized zeolitic nickel molybdate with Na+ is used as the adsorbent, which effectively separates C2 hydrocarbon mixtures.

10.
Sci Rep ; 12(1): 7554, 2022 05 12.
Artículo en Inglés | MEDLINE | ID: mdl-35551198

RESUMEN

Transmission electron microscopy (TEM) is an essential method in virology because it allows for direct visualization of virus morphology at a nanometer scale. Negative staining to coat virions with heavy metal ions must be performed before TEM observations to achieve sufficient contrast. Herein, we report that potassium salts of Preyssler-type phosphotungstates (K(15-n)[P5W30O110Mn+], M = Na+, Ca2+, Ce3+, Eu3+, Bi3+, or Y3+) are high-performance negative staining reagents. Additionally, we compare the staining abilities of these salts to those of uranyl acetate and Keggin-type phosphotungstate. The potassium salt of Preyssler-type phosphotungstates has the advantage of not requiring prior neutralization because it is a neutral compound. Moreover, the potassium counter-cation can be protonated by a reaction with H+-resin, allowing easy exchange of protons with other cations by acid-base reaction. Therefore, the counter-cations can be changed. Encapsulated cations can also be exchanged, and clear TEM images were obtained using Preyssler-type compounds with different encapsulated cations. Preyssler-type phosphotungstates may be superior negative staining reagents for observing virus. Polyoxotungstates (tungsten-oxide molecules with diverse molecular structures and properties) are thus promising tools to develop negative staining reagents for TEM observations.


Asunto(s)
Sales (Química) , Virus , Indicadores y Reactivos , Iones , Microscopía Electrónica de Transmisión , Coloración Negativa/métodos , Potasio , Coloración y Etiquetado
11.
J Am Chem Soc ; 144(17): 7693-7708, 2022 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-35438484

RESUMEN

Keggin-type phosphomolybdic acid (PMo12O40), treated with pyridine (Py), forms a crystalline material (PyPMo-HT) following heat treatment under an inert gas flow at ∼420 °C. Although this material is known to have attractive catalytic properties for gas-phase oxidation, the origin of this catalytic activity requires clarification. In this study, we investigated the crystal structure of PyPMo-HT. PyPMo-HT comprises a one-dimensional array of Keggin units and pyridinium cations (HPy), with an HPy/Keggin unit ratio of ∼1.0. Two oxygen atoms were removed from the Keggin unit during crystal structure transformation, which resulted in an electron being localized on the Mo atom in close contact with the adjacent Keggin unit. Upon the introduction of molecular oxygen, electron transfer from this Mo atom resulted in the formation of an electrophilic oxygen species that bridged two Keggin units. The electrophilic oxygen species acted as a catalytically active oxygen species, as confirmed by the selective oxidation of propylene. PyPMo-HT showed excellent catalytic activity for the selective oxidation of methacrolein, with the methacrylic acid yield being superior to that obtained with PMo12O40 and comparable to that obtained with an industrial Keggin-type polyoxometalate (POM) catalyst. The oxidation catalysis observed over PyPMo-HT provides a deeper understanding of POM-based industrial catalytic processes.


Asunto(s)
Molibdeno , Oxígeno , Aniones , Catálisis , Molibdeno/química , Oxígeno/química , Ácidos Fosfóricos , Polielectrolitos
12.
ACS Omega ; 6(36): 23564-23569, 2021 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-34549153

RESUMEN

Five types of niobium(V) oxides (Nb2O5) were synthesized by hydrothermal and heat treatment processes, and their structural properties and catalytic activities for the hydrogen absorption/desorption reactions of magnesium were characterized. The synthesized Nb oxides were dispersed on magnesium hydride (MgH2), a typical hydrogen storage material, using the ball-milling method. All the synthesized Nb oxides improved the reaction kinetics of the hydrogen desorption/absorption reactions. The catalytic activities for the hydrogen desorption were comparable, while the hydrogen absorption rates were significantly different for each synthesized Nb oxide. This difference can be explained by the structural stability of Nb2O5, which is related to the formation of a catalytically active state by the reduction of Nb2O5 during the ball-milling process. Notably, the highest catalytic effect was observed for Nb2O5 with a highly crystalline pyrochlore structure and a low specific surface area, suggesting that pyrochlore Nb2O5 is a metastable phase. However, only the amorphous Nb oxide was out of order, even though there is a report on the high catalytic activity of amorphous Nb oxide. This is attributed to the initial condensed state of amorphous Nb oxide, because particle size affects the dispersion state on the MgH2 surface, which is also important for obtaining high catalytic activity. Thus, it is concluded that Nb2O5 with lower stability of the crystal structure and smaller particle size shows better catalysis for both hydrogen desorption and absorption reactions.

13.
Angew Chem Int Ed Engl ; 60(33): 18328-18334, 2021 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-34056813

RESUMEN

Separation of C2 hydrocarbons, C2 H6 , C2 H4 , and C2 H2 , remains significant challenges in chemical industry. However, there are only few adsorbents that can effectively isolate C2 hydrocarbons from their mixtures particularly at a high temperature. Herein, we design a zeolitic octahedral metal oxide based on ϵ-Keggin polyoxometalates with metal ion linkers. Single gas adsorption of the material shows the different adsorption performances for the C2 hydrocarbons and the strong interaction of the material with the C2 hydrocarbons. Dynamic competitive adsorption experiments show that the material efficiently separates each of the binary C2 hydrocarbon mixtures and even the ternary C2 hydrocarbon mixtures with high selectivity. The material keeps high separation performance even the temperature was increased to 85 °C. The material is stable and is able to be reused without loss of the separation performance.

14.
Virology ; 559: 120-130, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33865075

RESUMEN

We isolated a novel Aquareovirus (hirame aquareovirus: HAqRV) from Japanese flounder Paralichthys olivaceus suffering from reovirus-like infection. In electron microscopy, the spherical virion (75 nm in diameter) was observed with multi-layered capsid structure. The viral genome consisted of 11 segments and regions encoding 7 virion structural proteins and 5 non-structural proteins were predicted. The deduced amino acid sequences of those proteins were highly similar to those of the aquareoviruses. However, the similarity of complete genome sequence between the HAqRV and other aquareoviruses was less than 60%. Phylogenetic analyses based on the deduced amino acid sequences suggested that the HAqRV is not classified into the known species of Aquareovirus. Pathogenicity of HAqRV was clearly demonstrated in accordance with Koch's postulates by experimental infection using Japanese flounder. The results suggest that the HAqRV is a new Aquareovirus species which is highly virulent for the Japanese flounder at early life stages.


Asunto(s)
Lenguado/virología , Genoma Viral , Filogenia , Reoviridae/clasificación , Reoviridae/genética , Animales , Anticuerpos Antivirales , Proteínas de la Cápside/genética , Línea Celular , Células Gigantes/virología , Hepatocitos/patología , Hepatocitos/virología , Reoviridae/aislamiento & purificación , Reoviridae/patogenicidad , Virión/genética , Secuenciación Completa del Genoma
15.
ACS Appl Mater Interfaces ; 13(16): 19138-19147, 2021 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-33870694

RESUMEN

The exploration of composition-structure-function relationship in proton-conducting solids remains a challenge in materials chemistry. Polyoxometalate-based compounds have been long considered as candidates for proton conductors; however, their low structural stability and a large decrease in conductivity under reduced relative humidity (RH) have limited their applications. To overcome such limitations, the hybridization of polyoxometalates with proton-conducting polymers has emerged as a promising method. Besides, 4f lanthanide ions possess a high coordination number, which can be utilized to attract water molecules and to build robust frameworks. Herein, a Preyssler-type polyoxometalate functionalized with a 9-coordinate Eu3+ (Eu[P5W30O110K]11-) is newly synthesized and combined with poly(allylamine) with amine moieties as protonation sites. The resulting robust crystalline composite exhibits an ultrahigh proton conductivity >10-2 S cm-1 at 368 K and 90% RH, which is still >10-3 S cm-1 at 50% RH, due to the strengthened and extended hydrogen-bonding network.

16.
Inorg Chem ; 59(22): 16557-16566, 2020 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-33100003

RESUMEN

Transition-metal oxide molecular wires are inorganic 1D polymers with elemental diversity. The properties of the materials are tuned by tuning the chemical compositions. The phosphovanadomolybdate molecular wire is synthesized, which is an isostructural material of the phosphomolybdate molecular wire. V is randomly located in the crystal to form {[(HPIIIO3)(MoVI5O15)(VVO3)]3-}n, which is incorporated into the material after the formation of the phosphomolybdate molecular wire. The heat-triggered redox reaction via the intramolecular electron-transfer and oxygen-transfer procedure is promoted after V substitution. Oxygen transfers from {VVO6} to {HPIIIO3}, and an electron transfers from {HPIIIO3} to {VVO6} with oxidation of the triangle {HPIIIO3} to the corner-sharing tetrahedral {PV2O7} and reduction of the octahedral {VVO6} to the pyramidal {VIVO5}. The material shows catalytic activity for the aerobic oxidation of alcohol to aldehyde, and good activity with high selectivity is obtained.

17.
ACS Omega ; 5(34): 21906-21912, 2020 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-32905312

RESUMEN

Magnesium is a promising hydrogen storage material but requires an efficient catalyst to enhance the sluggish kinetics of its hydrogen desorption/absorption reactions. Niobium catalysts have been shown to accomplish this, but the effective factors for catalysis on hydrogen desorption/absorption of Mg are not well understood. In order to investigate these aspects, various types of Nb oxides were synthesized and mixed with Mg, and their catalytic properties were investigated. The spray pyrolysis synthesis of Nb oxides at different temperatures produced homogeneous spherical particles with different degrees of crystallinity, while Nb oxide particles synthesized by simple calcination of ammonium niobium oxalate were nonuniform. These Nb oxides show significant catalytic activities for the hydrogen desorption/absorption of Mg, with amorphous oxides being more effective catalyst precursors than crystalline precursors. Metastable, amorphous Nb oxide is more easily converted to the reduced state, which is the catalytically active state for the reactions. In addition, Nb in the deactivated sample is in the oxidized state compared with the initially activated sample, and the catalytically active (reduced) state is recovered by reactions with hydrogen. Based on these findings, it is concluded that the chemical state of Nb is an important factor in catalyzing the desorption/absorption of hydrogen by Mg, and the catalytically active state can be preserved without further treatments.

18.
Dalton Trans ; 49(29): 9972-9982, 2020 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-32484170

RESUMEN

A chabazite (CHA zeolite) was synthesized using high-silica faujasite (FAU) zeolites with a Si/Al ratio of 93, an additional alumina source (aluminum hydroxide) combined with seed crystals, and N,N,N-trimethyl-1-adamantammonium hydroxide. We compared the crystallization behavior of the starting material (HSY + Al) with that of other combinations of silica/alumina sources (high-silica and low-silica FAU, fumed silica, and aluminum hydroxide). HSY + Al rapidly yielded nanosized CHA zeolites with a crystal size of approximately 70 nm, exhibited high product crystallinity and high yield and offered a wide synthesis window. A combination of analytic experiments using electrospray-ionization mass spectrometry and nuclear magnetic resonance (NMR) suggested that in the early stage, the pre-introduced CHA seeds provide a crystal nucleus and the FAU zeolites decompose to form oligomer species in the liquid phase. Meanwhile, aluminum hydroxide retains its solid phase. Subsequent crystallization of the zeolites is accelerated by the liquid silicate oligomer and solid aluminate sources, resulting in a high yield and rapid synthesis of nanosized CHA zeolites. We observed that phosphorus-modified CHA zeolites synthesized using HSY + Al perform well as a catalyst for ethanol conversion reactions. Controlled Si/Al ratios and additional phosphorus modifications improve catalytic durability, thereby exhibiting a higher propylene yield from the reaction within the zeolite pore system.

19.
Dalton Trans ; 49(9): 2766-2770, 2020 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-32065176

RESUMEN

Simple synthetic procedures for accessing novel metal-substituted tungstosulfates [SMW11O39]4- with Keggin-type structures were developed based on the reaction of metal ions (M = Mn2+, Co2+, Ni2+, and Cu2+) with lacunary tungstosulfate, [SW11O39]6-, which was obtained by treating [SW12O40]2- with a weak base in acetone. All metal-substituted tungstosulfates were characterized by elemental analysis, X-ray crystallography, ESI-MS, IR, Raman, UV-Vis and cyclic voltammetry analyses.

20.
Inorg Chem ; 58(18): 12272-12279, 2019 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-31465205

RESUMEN

Phosphomolybdates with different P species exhibiting a 1D molecular structure are synthesized. The materials are constructed by a {[MoVI6O21]6-}n molecular tube as a shell with trapping a redox-active species P in the center. The building units ([(HPIIIO3)MoVI6O18]2- or [(PV2O7)MoVI12O36]4-) form at room temperature, which further polymerize linearly along the c-axis. Interestingly, the material shows an unusual heat-triggered intramolecular redox property, which undergoes an electron-transfer-oxygen-transfer procedure from [{(HPIIIO3)MoVI6O18]2-}n to {[(PV2O7)MoVI12O36]4-}n/2. The crystal structure of the material is stable during the oxidation reaction, while the central P is oxidized and the local structure changes.

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