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1.
Acta Crystallogr E Crystallogr Commun ; 80(Pt 1): 22-24, 2024 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-38312157

RESUMEN

The asymmetric unit of the title compound, µ-biphenyl-4,4'-di-sulfonato-bis-(aqua-lithium), [Li2(C12H8O6S2)(H2O)2] or Li2[Bph(SO3)2](H2O)2, consists of an Li ion, half of the diphenyl-4,4'-di-sulfonate [Bph(SO3 -)2] ligand, and a water mol-ecule. The Li ion exhibits a four-coordinate tetra-hedral geometry with three oxygen atoms of the Bph(SO3 -)2 ligands and a water mol-ecule. The tetra-hedral LiO4 units, which are inter-connected by biphenyl moieties, form a layer structure parallel to (100). These layers are further connected by hydrogen-bonding inter-actions to yield a three-dimensional network.

2.
Nat Commun ; 14(1): 1472, 2023 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-36928582

RESUMEN

Intercalated metal-organic frameworks (iMOFs) based on aromatic dicarboxylate are appealing negative electrode active materials for Li-based electrochemical energy storage devices. They store Li ions at approximately 0.8 V vs. Li/Li+ and, thus, avoid Li metal plating during cell operation. However, their fast-charging capability is limited. Here, to circumvent this issue, we propose iMOFs with multi-aromatic units selected using machine learning and synthesized via solution spray drying. A naphthalene-based multivariate material with nanometric thickness allows the reversible storage of Li-ions in non-aqueous Li metal cell configuration reaching 85% capacity retention at 400 mA g-1 (i.e., 30 min for full charge) and 20 °C compared to cycling at 20 mA g-1 (i.e., 10 h for full charge). The same material, tested in combination with an activated carbon-based positive electrode, enables a discharge capacity retention of about 91% after 1000 cycles at 0.15 mA cm-2 (i.e., 2 h for full charge) and 20 °C. We elucidate the charge storage mechanism and demonstrate that during Li intercalation, the distorted crystal structure promotes electron delocalization by controlling the frame vibration. As a result, a phase transition suppresses phase separation, thus, benefitting the electrode's fast charging behavior.

3.
ACS Nano ; 15(2): 2719-2729, 2021 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-33525874

RESUMEN

Low resistance of Li-intercalated negative electrodes is important for the safe and fast charging required for large-scale batteries. Here, we demonstrated that nanosized two-dimensional crystalline aromatic dicarboxylate negative electrode materials synthesized via spray drying exhibit low internal resistances at approximately 0.7 V vs Li/Li+, while retaining flat potential profiles. The spray-dried sample with a hollow structure is crushed into nanoflakes during ink preparation for electrode coating and forms a uniform and highly dispersed electrode structure. The charge-discharge evaluation indicates that the nanoflake sample showed smaller charge-discharge polarization than the bulk sample with stable cycling characteristics, resulting in significant high-rate property enhancement. Charge-transfer resistance of the nanoflake sample exhibits the lowest value (ca. 2.2 Ω cm2) among those reported for existing intercalation electrodes (5.2 to 235 Ω cm2). In comparison of the negative electrodes, the estimated maximum current density without Li deposition (ca. 316 mA cm-2) is more than 1 order of magnitude higher than that for currently used graphite (ca. 11 mA cm-2) and is also higher than those for high-rate oxides (137-298 mA cm-2). The resistance-crystal correlation using multiple regression analysis predictions and its verification reveal that this low resistance is owing to an improved Li acceptability associated with selective structural defects induced by the loss of incorporated crystallized water during drying. The crystal plane exposed by the selective structural defects is perpendicular to electronic and ionic conduction directions inside the solid, resulting in improved kinetics. Therefore, the proposed negative electrode allows safe and fast charging, with easy scale-up and sustainable resources.

4.
Foods ; 9(5)2020 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-32429096

RESUMEN

Hydrochloric acid (HCl)-treated wheat protein (HWP) is widely used in various products, including foods, cosmetics and shampoos. Recently, immediate hypersensitivity towards facial soap containing HWP has been reported. HCl treatment of protein causes hydrolysis not only of main-chain amide bonds (peptide-bond hydrolysis) but also of side-chain ones (deamidation). We have already reported that gliadin, the main allergen in wheat, reduces allergenicity and increases digestibility by deamidation, indicating that deamidation and peptide-bond hydrolysis are effective to reduce the allergenicity of wheat protein. However, transdermally administered HWP is assumed to induce sensitization to orally administered wheat protein even in those who have been taking wheat products daily before sensitization. The present study was conducted to examine which structural change is responsible for the induction of cutaneous sensitization by comparing the allergenicity of deamidated and/or peptide-bond-hydrolyzed wheat gliadin. Because we have developed a deamidation method without causing peptide-bond hydrolysis, only deamidated wheat gliadin is available. Therefore, after deamidated-only, hydrolyzed-only, and deamidated and hydrolyzed gliadins were transdermally administered to mice for several weeks, the corresponding gliadin was intraperitoneally administered and allergenicity was evaluated. Transdermal administration of deamidated and hydrolyzed gliadin induced severe allergic reaction, while that of deamidated-only and hydrolyzed-only gliadin showed almost no allergic response. This result indicates that both deamidation and peptide-bond hydrolysis are necessary to increase the allergenic potency of transdermally administered wheat gliadin.

5.
J Nutr Sci Vitaminol (Tokyo) ; 65(Supplement): S134-S138, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31619614

RESUMEN

Starch starts to retrograde and form a crystalline structure immediately after gelatinization upon heating with water. The retrogradation rate is affected by the starch granule size, degree of polymerization, amylose/amylopectin ratio, starch concentration, water content, and storage temperature. Retrogradation of amylose occurs over a short term, while that of amylopectin occurs over a long term. The degree of starch gelatinization and retrogradation is evaluated by the degree of crystalline structure formation, viscoelastic properties, molecular mobility, and enzymatic digestibility using thermal, rheological, spectroscopic, and chemical techniques. The addition of carbohydrates, lipids, proteins, salts, acids, polyols, and enzymes changes the starch retrogradation rate, and some of these prevent retrogradation.


Asunto(s)
Conservación de Alimentos/métodos , Almacenamiento de Alimentos/métodos , Calor , Oryza/química , Almidón/química , Amilopectina/química , Amilosa/química , Cristalización , Gelatina , Polimerizacion , Temperatura , Sustancias Viscoelásticas/química , Agua
6.
Inorg Chem ; 58(4): 2379-2385, 2019 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-30730714

RESUMEN

Host-guest materials based on coordination polymers (CPs) are currently emerging as potential candidates for battery applications. In this context, we describe the preparation of three-dimensional network structures containing BF4 anions and water molecules in the one-dimensional (1D) channels via hydrothermal reactions between Cu(BF4)2 and 4,4'-bipyridine or 1,2-di-4-pyridylethylene. A systematic characterization of the obtained CPs using single-crystal X-ray diffraction, X-ray absorption fine structure, and an electrochemical test was performed. The results showed that the BF4 anions were electrochemically reduced to BF3 in the cavities of the CPs, with concomitant elimination of a leaving fluoride at room temperature. Using this electrochemical property, a prototype battery, in which the CPs act as the anode and graphite as the cathode, was demonstrated. The cell exhibited a practical discharge potential of ∼1.5 V. This constitutes the first demonstration of CPs showing electrochemical B-F bond activation in the 1D channels and rocking-chair-type fluoride insertion and extraction by changes in the electric potential.

7.
Nutrients ; 10(10)2018 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-30326572

RESUMEN

Inhibiting starch hydrolysis into sugar could reduce postprandial blood glucose elevation and contribute to diabetes prevention. Here, both buckwheat and wheat albumin that inhibited mammalian α-amylase in vitro suppressed blood glucose level elevation after starch loading in vivo, but it had no effect after glucose loading. In contrast to the non-competitive inhibition of wheat α-amylase inhibitor, buckwheat albumin acted in a competitive manner. Although buckwheat α-amylase inhibitor was readily hydrolysed by digestive enzymes, the hydrolysate retained inhibitory activity. Together with its thermal stability, this suggests its potential use in functional foods that prevent diabetes.


Asunto(s)
Albúminas/farmacología , Glucemia/efectos de los fármacos , Fagopyrum/química , Inhibidores de Glicósido Hidrolasas/farmacología , Hiperglucemia/tratamiento farmacológico , Hipoglucemiantes/farmacología , Proteínas de Plantas/farmacología , Periodo Posprandial , alfa-Amilasas/antagonistas & inhibidores , Albúminas/aislamiento & purificación , Animales , Biomarcadores/sangre , Glucemia/metabolismo , Inhibidores de Glicósido Hidrolasas/aislamiento & purificación , Humanos , Hiperglucemia/sangre , Hipoglucemiantes/aislamiento & purificación , Insulina/sangre , Masculino , Proteínas de Plantas/aislamiento & purificación , Estabilidad Proteica , Ratas Wistar , Triticum/química , alfa-Amilasas/metabolismo
8.
Genesis ; 55(12)2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-29086479

RESUMEN

The viral 2A peptides have recently been used for bicistronic expression in various organisms. In this system, a single mRNA that codes for two proteins flanking the 2A peptide can be translated simultaneously into each protein by ribosomal skipping at this peptide sequence. Here, we tested the function of the Thosea asigna insect virus 2A (T2A) peptide in the branchiopod crustacean Daphnia magna-an emerging model of evolutionary developmental biology. First, we used transgenic Daphnia that expresses a potential bicistronic RNA containing mCherry and histone H2B- green fluorescent protein (GFP) open reading frames upstream and downstream of the T2A sequence, respectively. Microscopic observation revealed difference of localization of the two proteins in the cell, homogenous distribution of mCherry and nuclear localization of H2B-GFP. Second, we changed localization of mCherry from cytoplasm to plasma membrane by attachment of a consensus myristoylation motif in the bicistronic reporter. RNA that codes for this new bicistronic reporter was injected into eggs. At gastrulation stage, we found spectrally distinct fluorescence with enough intensity and resolution to detect membrane localized mCherry and nuclear GFP. These results indicate that the T2A peptide functions in D. magna and T2A-mediated bicistronic expression would be a promising tool for evo-devo studies of this species.


Asunto(s)
Animales Modificados Genéticamente/genética , Daphnia/genética , Genes/genética , Proteínas Virales/genética , Animales , Animales Modificados Genéticamente/crecimiento & desarrollo , Membrana Celular/genética , Membrana Celular/ultraestructura , Citoplasma/genética , Citoplasma/ultraestructura , Daphnia/crecimiento & desarrollo , Regulación del Desarrollo de la Expresión Génica , Genes Reporteros , Proteínas Fluorescentes Verdes/genética , Óvulo/crecimiento & desarrollo , Péptidos/genética , Ribosomas/genética
9.
PLoS One ; 12(10): e0186112, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29045453

RESUMEN

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated system (Cas) is widely used for mediating the knock-in of foreign DNA into the genomes of various organisms. Here, we report a process of CRISPR/Cas-mediated knock-in via non-homologous end joining by the direct injection of Cas9/gRNA ribonucleoproteins (RNPs) in the crustacean Daphnia magna, which is a model organism for studies on toxicology, ecology, and evolution. First, we confirmed the cleavage activity of Cas9 RNPs comprising purified Cas9 proteins and gRNAs in D. magna. We used a gRNA that targets exon 10 of the eyeless gene. Cas9 proteins were incubated with the gRNAs and the resulting Cas9 RNPs were injected into D. magna eggs, which led to a typical phenotype of the eyeless mutant, i.e., eye deformity. The somatic and heritable mutagenesis efficiencies were up to 96% and 40%, respectively. Second, we tested the CRISPR/Cas-mediated knock-in of a plasmid by the injection of Cas9 RNPs. The donor DNA plasmid harboring the fluorescent reporter gene was designed to contain the gRNA recognition site. The co-injection of Cas9 RNPs together with the donor DNAs resulted in generation of one founder animal that produced fluorescent progenies. This transgenic Daphnia had donor DNA at the targeted genomic site, which suggested the concurrent cleavage of the injected plasmid DNA and genomic DNA. Owing to its simplicity and ease of experimental design, we suggest that the CRISPR/Cas-mediated knock-in method represents a promising tool for studying functional genomics in D. magna.


Asunto(s)
Sistemas CRISPR-Cas/genética , Reparación del ADN por Unión de Extremidades/genética , Daphnia/genética , Técnicas de Sustitución del Gen , Animales , Animales Modificados Genéticamente , Secuencia de Bases , Técnicas de Inactivación de Genes , Genes Reporteros , Sitios Genéticos , Células Germinativas/metabolismo , Fenotipo , Plásmidos/metabolismo , Ribonucleoproteínas/metabolismo , Transgenes
10.
Biosci Biotechnol Biochem ; 81(4): 743-749, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28103745

RESUMEN

Relation between the thermodynamic parameters obtained from water sorption isotherms and the degree of reduction in the glass transition temperature (Tg), accompanied by water sorption, was quantitatively studied. Two well-known glassy food materials namely, wheat gluten and maltodextrin were used as samples. The difference between the chemical potential of water in a solution and that of pure water ([Formula: see text]), the difference between the chemical potential of solid in a solution and that of a pure solid ([Formula: see text]), and the change in the integral Gibbs free energy ([Formula: see text]) were obtained by analyzing the water sorption isotherms using solution thermodynamics. The parameter [Formula: see text] correlated well with ΔTg (≡Tg - Tg0; where Tg0 is the glass transition temperature of dry material), which had been taken to be an index of plasticizing effect. This indicates that plasticizing effect of water on foods can be evaluated through the parameter [Formula: see text].


Asunto(s)
Análisis de los Alimentos , Glútenes/química , Polisacáridos/química , Agua/química , Vidrio/química , Plastificantes/química , Soluciones , Temperatura , Termodinámica , Temperatura de Transición
11.
Dalton Trans ; 45(39): 15399-15405, 2016 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-27602984

RESUMEN

The proton conducting properties of two different structural types of porous coordination polymers [La2(ox)3(H2O)6]·4H2O (1) and [Er2(ox)3(H2O)6]·12H2O (2), where ox2- = oxalate, were investigated. 1 has a two-dimensional layered structure, whereas 2 has a three-dimensional structure. Both 1 and 2 have hydrophilic one-dimensional channels filled by lattice water molecules with hydrogen-bonding networks. The coordinated H2O molecules are Lewis acidic due to the lanthanoid ions donating protons to lattice-filling H2O molecules, thereby forming efficient proton conduction pathways. Alternating-current impedance analyses of 1 and 2 indicated significant proton conduction (σ = 3.35 × 10-7 S cm-1 at 368 K for 1, 1.79 × 10-6 S cm-1 at 363 K for 2 under RH = 100%, with Ea = 0.35 eV for 1 and 0.47 eV for 2), which was attributed to the Grotthuss mechanism via the lattice H2O molecules.

12.
J Agric Food Chem ; 64(24): 4882-90, 2016 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-27228466

RESUMEN

The suppressive effect of rice albumin (RA) of 16 kDa on elevation of blood glucose level after oral loading of starch or glucose and its possible mechanism were examined. RA suppressed the increase in blood glucose levels in both the oral starch tolerance test and the oral glucose tolerance test. The blood glucose concentrations 15 min after the oral administration of starch were 144 ± 6 mg/dL for control group and 127 ± 4 mg/dL for RA 200 mg/kg BW group, while those after the oral administration of glucose were 157 ± 7 mg/dL for control group and 137 ± 4 mg/dL for RA 200 mg/kg BW group. However, in the intraperitoneal glucose tolerance test, no significant differences in blood glucose level were observed between RA and the control groups, indicating that RA suppresses the glucose absorption from the small intestine. However, RA did not inhibit the activity of mammalian α-amylase. RA was hydrolyzed to an indigestible high-molecular-weight peptide (HMP) of 14 kDa and low-molecular-weight peptides by pepsin and pancreatin. Furthermore, RA suppressed the glucose diffusion rate through a semipermeable membrane like dietary fibers in vitro. Therefore, the indigestible HMP may adsorb glucose and suppress its absorption from the small intestine.


Asunto(s)
Albúminas/metabolismo , Glucosa/metabolismo , Insulina/sangre , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Animales , Glucemia/metabolismo , Digestión , Mucosa Gástrica/metabolismo , Prueba de Tolerancia a la Glucosa , Masculino , Oryza/química , Periodo Posprandial , Ratas , Ratas Wistar , alfa-Amilasas/metabolismo
13.
Int J Mol Sci ; 16(1): 2117-29, 2015 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-25607735

RESUMEN

Phytate-removed and deamidated soybean ß-conglycinin (PrDS) prepared by ion-exchange resins was supplemented to be 4% in the diet administered to ovariectomized rats to investigate its preventive effect on osteoporosis. The apparent calcium absorption rate decreased following ovariectomy and was not replenished by oral administration of phytate-removed soybean ß-conglycinin (PrS) or casein. On the other hand, administration of PrDS restored the calcium absorption rate to the same level as the sham group. Markers of bone resorption, such as serum parathyroid hormone (PTH) and urinary deoxypyridinoline (DPD), increased, and the bone mineral density and breaking stress decreased following ovariectomy. However, PrDS supplementation suppressed the changes caused by the decrease in calcium absorption from the small intestine. Therefore, PrDS supplementation shows promise for the prevention of postmenopausal osteoporosis.


Asunto(s)
Amidas/aislamiento & purificación , Antígenos de Plantas/administración & dosificación , Antígenos de Plantas/uso terapéutico , Globulinas/administración & dosificación , Globulinas/uso terapéutico , Osteoporosis/tratamiento farmacológico , Osteoporosis/prevención & control , Ácido Fítico/aislamiento & purificación , Proteínas de Almacenamiento de Semillas/administración & dosificación , Proteínas de Almacenamiento de Semillas/uso terapéutico , Proteínas de Soja/administración & dosificación , Proteínas de Soja/uso terapéutico , Absorción Fisiológica/efectos de los fármacos , Administración Oral , Aminoácidos/orina , Animales , Antígenos de Plantas/farmacología , Fenómenos Biomecánicos/efectos de los fármacos , Densidad Ósea/efectos de los fármacos , Huesos/efectos de los fármacos , Huesos/fisiopatología , Femenino , Globulinas/farmacología , Minerales/metabolismo , Osteoporosis/sangre , Osteoporosis/orina , Ovariectomía , Hormona Paratiroidea/sangre , Ratas Wistar , Proteínas de Almacenamiento de Semillas/farmacología , Proteínas de Soja/farmacología
14.
J Agric Food Chem ; 62(13): 2845-52, 2014 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-24617642

RESUMEN

Gliadin is the principal allergen of wheat-dependent exercise-induced anaphylaxis (WDEIA). The primary structure of IgE-binding epitopes in wheat gliadin includes tandem sequencing sites of glutamine residues. Therefore, deamidation would be an effective approach to reduce the allergenicity of wheat proteins. In our previous study, we deamidated wheat gliadin without causing peptide-bond hydrolysis or polymerization by use of carboxylated cation-exchange resins, and we found that the deamidated gliadin scarcely reacted with the sera of patients radioallergosorbent test (RAST)-positive to wheat. In this study, we examined the allergenicity of deamidated gliadin in a mouse model of wheat-gliadin allergy. Oral administration of deamidated gliadin to gliadin-sensitized mice suppressed enhancement in intestinal permeability, serum allergen level, serum allergen-specific IgE level, mast-cell-surface expression of FcεRI, and serum and intestinal histamine levels. Our results indicate that gliadin deamidated with no peptide-bond hydrolysis by cation-exchange resins has low allergenicity even under in vivo conditions.


Asunto(s)
Anafilaxia/prevención & control , Epítopos/química , Epítopos/inmunología , Gliadina/química , Gliadina/inmunología , Inmunoglobulina E/inmunología , Triticum/inmunología , Hipersensibilidad al Trigo/prevención & control , Anafilaxia/inmunología , Animales , Desaminación , Humanos , Hidrólisis , Inmunoglobulina E/sangre , Intestinos/inmunología , Masculino , Ratones , Ratones Endogámicos BALB C , Triticum/química , Hipersensibilidad al Trigo/inmunología
15.
Acta Crystallogr Sect E Struct Rep Online ; 69(Pt 4): m216, 2013 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-23634010

RESUMEN

In the title compound, {[Zn(C8H4O4)(C6H6N2O)2]·C6H6N2O} n , the Zn(II) ion exhibits a tetra-hedral coordination environment defined by two benzene-1,4-dicarboxylate dianions and two 4-pyridinealdoxime ligands. The dianions bridge the Zn(II) ions, giving a zigzag chain along the b axis. Adjacent chains are connected by O-H⋯O hydrogen bonds, forming a cavity in which an uncoordinating 4-pyridine-aldoxime mol-ecule is located; this mol-ecule is linked by O-H⋯O and O-H⋯N hydrogen bonds to the zigzag chain.

16.
Inorg Chem ; 52(4): 2142-9, 2013 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-23383954

RESUMEN

[Co(4)(phcina)(6)(OH)(2)(H(2)O)(4)]·2H(2)O (1) (phcina = α-phenylcinnamate), obtained as pink needles by hydrothermal technique, consists of two edge-sharing pairs of octahedral CoO(6) connected by their apexes to form diamond-chains. The magnetic chains are isolated from one another without chemical bond at 17 Å by the nonmagnetic bulky organic ligand. It exhibits hidden canting below the long-range antiferromagnetic (AF) ordering at 5.5 K. A metamagnetic critical field of only 30 Oe at 2 K suffices to overcome the weak through space magnetic interaction between chains and reverse the moments within the chains to give a canted AF reaching only (1)/(4) of the required moment for all parallel moment alignment. The anisotropy measured on aligned crystals, using dc and ac modes, estimates g(||b) = 6.5 and g(⊥b) = 3.25, thus eliminating an Ising or a Heisenberg magnetic dimensionality while suggesting an easy-plane AF. Weak frequency dependence of the ac-susceptibilities below the transition temperature is associated with domain structure in the ordered state, and absence of it well above T(N) eliminates single-chain magnetism. It is inferred that the competition between the strong AF coupling between the edge-sharing pairs, which dominates the high temperature susceptibility, and the ferromagnetic coupling within the pairs, results in a canting of the moments within each chain, where the moments are out of the ac-plane by an estimated 13°. In zero-field the moments of adjacent chains are antiparallel resulting in a compensated system, i.e., hidden canting.


Asunto(s)
Cinamatos/química , Cobalto/química , Hidróxidos/química , Compuestos Organometálicos/química , Temperatura , Cristalografía por Rayos X , Campos Magnéticos , Modelos Moleculares , Compuestos Organometálicos/síntesis química
17.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 5): m643-4, 2012 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-22590133

RESUMEN

The asymmetric unit of the title compound, {[Ce(2)(C(8)H(4)O(4))(C(10)H(8)N(2))(H(2)O)(12)](C(8)H(4)O(4))(2)}(n), consists of half a Ce(III) cation, a quarter of a coordinated benzene-1,4-dicarboxyl-ate (bdc(2-)) dianion, a quarter of a 4,4'-bipyridine (bpy) mol-ecule, three water mol-ecules and a half of an uncoordinated benzene-1,4-dicarboxyl-ate dianion. The Ce(III) ion is located on a twofold rotation axis and exhibits a distorted trigonal prism square-face tricapped coordination geometry. The coordinated and uncoordinated bdc(2-) ions and the bpy mol-ecule lie about special positions of site symmetries 2/m, m and 2/m, respectively. The Ce(III) ions are bridged by the bdc(2-) and bpy ligands, giving a sheet structure parallel to the ac plane. The uncoordinated bdc(2-) dianion exists between the sheets and links the sheets by inter-molecular O-H⋯O hydrogen bonds between the uncoordinated bdc(2-) and coordinated water mol-ecules. A π-π stacking inter-action between the uncoordinated bdc(2-) dianion and the bpy ligand [centroid-centroid distance = 3.750 (4) Å] is also observed.

18.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 10): o2636, 2011 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-22064366

RESUMEN

The title compound, C(10)H(10)N(2) (2+)·C(8)Br(4)O(4) (2-)·2H(2)O, consists of a tetra-bromo-terephthalate dianion, a 4,4'-bipyridinium dication and two solvent water mol-ecules. Crystallographic inversion centers are situated at the center of the aromatic ring of the dianion as well as at the midpoint of the carbon-carbon bond connecting the pyridine rings in the dication. In the crystal, inter-molecular N-H⋯O hydrogen-bonding inter-actions between tetra-bromo-terephthalate dianions and protonated 4,4'-bipyridinium dications result in the formation of a chain-like structure. Further O-H⋯O hydrogen bonds between carboxyl-ate O atoms and water mol-ecules lead to the formation of a two-dimensional network in the crystal structure.

19.
Nano Lett ; 11(2): 361-4, 2011 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-21204550

RESUMEN

Herein we demonstrate the extra-low-temperature oxygen storage capacity (OSC) of cerium oxide nanocrystals with cubic (100) facets. A considerable OSC occurs at 150 °C without active species loading. This temperature is 250 °C lower than that of irregularly shaped cerium oxide. This result indicates that cubic (100) facets of cerium oxide have the characteristics to be a superior low-temperature catalyst.


Asunto(s)
Cerio/química , Cristalización/métodos , Nanoestructuras/química , Nanoestructuras/ultraestructura , Nanotecnología/métodos , Oxígeno/química , Oxígeno/aislamiento & purificación , Frío , Sustancias Macromoleculares/química , Ensayo de Materiales , Conformación Molecular , Tamaño de la Partícula , Propiedades de Superficie
20.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 11): m1523-4, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22219771

RESUMEN

The title compound, [Cu(2)(C(13)H(9)N(4))(2)(HSO(4))(2)]·2CH(3)OH, consists of discrete centrosymmetric dinuclear complex mol-ecules and methanol solvent mol-ecules. The Cu(II) atom shows a square-pyramidal coordination geometry and is bonded to four N atoms of the two bis-chelating 3,5-bis-(2-pyrid-yl)pyrazol-ate ions (bpypz(-)) and one O atom of the hydrogensulfate ion. The bpypz(-) ligands in the complex mol-ecule are virtually coplanar [dihedral angle between the mean ligand planes = 0.000(1)°] with the Cu(II) atom deviating in opposite directions from their best plane by 0.2080 (12) Å. π-π stacking inter-actions between the pyridyl and pyrazole rings [centroid-centroid distance = 3.391 (3) Å] and strong O-H⋯O hydrogen bonds between the hydrogensulfate ligands and the methanol mol-ecules assemble the mol-ecules into a one-dimensional polymeric structure extending along the a axis. The methanol mol-ecule acts both as an accepter and a donor in the hydrogen bonding.

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