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2.
Dalton Trans ; 48(33): 12421-12429, 2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31265027

RESUMO

The reactions of [Ru2(O2CCH3)4Cl] with 2-aminopyridine (Hamp) and 2-amino-4-methylpyridine (Hammp) afforded two novel Ru2 complexes, [Ru2(amp)4Cl2] (1) and [Ru2(ammp)4Cl2] (2), respectively. Single crystal X-ray diffraction analyses revealed that 1 and 2 adopted typical paddlewheel-type structures, where the Ru2 units are coordinated with four aminopyridinate ligands with a cis-2:2 arrangement at the equatorial positions and two chloride ligands at the axial positions. The stabilities of 1 and 2 were supported by unrestricted density functional theory (uDFT) calculations. The zero-point energies of the three structural isomers (trans-2:2, 3:1, and 4:0 arrangements) of 1 and 2 were less stable than those of the respective cis-2:2 arrangements. Temperature-dependences of the magnetic susceptibility measurements and uDFT calculations showed that the oxidation and spin states of the Ru2 units in 1 and 2 were commonly Ru26+ and triplet states, respectively. Cyclic voltammetry showed that 1 and 2 underwent one-electron reduction processes, i.e., 1/1- and 2/2-, at redox potentials (E1/2) of -0.08 and -0.18 V vs. SCE, respectively. These results agreed well with the DFT-calculated E1/2 values of 1 (-0.08 V vs. SCE) and 2 (-0.18 V vs. SCE) and were theoretically attributed to Ru2-centred (δ*(Ru2)) redoxes. Moreover, 1 and 2 showed unique near-infrared absorption bands at approximately 1200-1500 nm, which were theoretically attributed to the ligand-to-metal charge transfer (LMCT) with π(amp or ammp) →δ*(Ru2) transition characteristics.

3.
Dalton Trans ; 48(27): 10174-10179, 2019 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-31187849

RESUMO

The crystal structure of a new magnesium(ii) complex, [Mg(dmso)6][BPh4]2 (1) (dmso: dimethylsulfoxide), was determined, and the reason for the observed structure was clarified by conformational analysis. For a dmso-ligand arm, three conformations, α, ß, and γ, are possible. The α-arm is the most energetically favourable and is suitable for reducing the steric repulsion between the arms; the ß-arm is less energetically favourable, but can be stabilized by interaction with surroundings (e.g. CHπ interaction); the γ-arm is not energetically favourable, but is effective in reducing the size of the complex cation. From the conformational analysis, the most stable conformer of the [Mg(dmso)6]2+ complex cation was found to be the α6 conformer, and the complex cation in dmso solution was predicted to exist as a mixture of α6, α5ß, and trans-α4ß2 species. On the contrary, in the crystal structure, the trans-ß2γ4 species, considered to be unstable, was observed. From the conformational analysis in the tetraphenylborate surroundings, the trans-ß2γ4 structure was found to become more stable, due to its small size suitable for crystal packing with bulky tetraphenylborate anions.

4.
Langmuir ; 35(9): 3302-3307, 2019 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-30744379

RESUMO

We report a biomimetic polyelectrolyte based on amphiphilic polymer nanosheet multilayer films. Copolymers of poly( N-dodecylacrylamide- co-vinylphosphonic acid) [p(DDA/VPA)] form a uniform monolayer at the air-water interface. By depositing such monolayers onto solid substrates using the Langmuir-Blodgett (LB) method, multilayer lamellae films with a structure similar to a bilayer membrane were fabricated. The proton conductivity at the hydrophilic interlayer of the lamellar multilayer films was studied by impedance spectroscopy under temperature- and humidity-controlled conditions. At 60 °C and 98% relative humidity (RH), the conductivity increased with increasing mole fraction of VPA ( n) up to 3.2 × 10-2 S cm-1 for n = 0.41. For a film with n = 0.45, the conductivity decreased to 2.2 × 10-2 S cm-1 despite the increase of proton sources. The reason for this decrease was evaluated by studying the effect of the distance between the VPAs ( lVPA) on the proton conductivity as well as their activation energy. We propose that for n = 0.41, lVPA is the optimal distance not only to form an efficient two-dimensional (2D) hydrogen bonding network but also to reorient water and VPA. For n = 0.45, on the other hand, the lVPA was too close for a reorientation. Therefore, we concluded that there should be an optimal distance to obtain high proton conductivity at the hydrophilic interlayer of such multilayer films.

5.
Dalton Trans ; 48(2): 395-399, 2019 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-30523349

RESUMO

Three tetracoordinated cobalt(ii) complexes with a series of unsymmetrical bidentate ligands were synthesized and crystallographically characterized. Although their static magnetic properties are similar, their dynamic magnetic properties differ drastically depending indirectly on intermolecular hydrogen-bonding interactions.

6.
Dalton Trans ; 46(46): 16306-16314, 2017 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-29140393

RESUMO

The magnetostructural correlation of the hexakis-dmso cobalt(ii) complex, [Co(dmso)6](BPh4)2 (dmso: dimethylsulfoxide), was investigated by single-crystal X-ray diffraction study and magnetic measurements. The magnetic analysis concluded the negative Δ value (H = Δ(L - 2/3) + E(L - L) - (3/2)κλL·S + ß[-(3/2)κLu + geSu]·Hu (u = x, y, z)), and this was explained by the tetragonal elongation of the octahedral geometry. The magnetostructural correlation was ascertained by both the angular overlap model calculation and the density functional theory calculation.

7.
ACS Appl Mater Interfaces ; 9(44): 38181-38186, 2017 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-29064659

RESUMO

To make a porous material with high magnetic ordering temperature is challenging because the low density of the material is adverse to the dense magnetic moment, a prerequisite to high-performance magnets. Herein, we report a hollow magnetic metal-organic framework (MMOF) [Co3(bpdc)3(tpt)0.66] 1 (H2bpdc = 4,4'-biphenyldicarboxylic acid) with a Langmuir surface area of 1118 m2/g and spin-canted long-range magnetic ordering up to 22 K. Such a high performance is owing to the unique antiferromagnetic Kagomé lattice made of ferromagnetic Co3 clusters and conjugated 2,4,6-tri(4-pyridinyl)-1,3,5-triazine (tpt) ligands, which is closely coupled with each other via double-interpenetration of the porous networks. Moreover, a parameter defined as the product of magnetic ordering/blocking temperature and the surface area for measuring the performance of porous molecular magnets is proposed.

8.
Dalton Trans ; 46(44): 15178-15180, 2017 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-29067379

RESUMO

An unusual Cu(ii) coordination polymer [Cu(Him)2(L)] (1) having a 4,4'-{[1,2-phenylene bis-(methylene)]bis(oxy)}dibenzoic acid ligand and an imidazole ligand possessing a 1D zig-zag chain was constructed and its magnetic behaviour was investigated, which indicated a magnetic phase transition below 25 K as well as long-range magnetic ordering.

9.
Rinsho Shinkeigaku ; 57(7): 391-394, 2017 07 29.
Artigo em Japonês | MEDLINE | ID: mdl-28652521

RESUMO

An 80-year-old woman had an aortic valve replacement 1 month before admission and took warfarin for transient atrial fibrillation. She developed a disturbance of consciousness and left hemiplegia. On admission, the right radial artery was slightly palpable. Head MRI images showed a hyper-intense area in the right middle cerebral artery territory. MRA images showed an occlusion of the right M1 distal site and decreased signal at the right internal carotid artery. Contrast CT images of the ascending aorta showed an embolus in the innominate artery. She was diagnosed with an innominate artery saddle embolus and occlusion of the right cerebral artery due to cardiac embolism. She was treated with a heparin infusion and warfarin. She recovered consciousness and from hemiplegia gradually. Recanalization of the innominate artery and right cerebral artery was confirmed. In cases where the radial artery is slightly palpable, it is necessary to consider an innominate artery saddle embolus in addition to aortic dissection.


Assuntos
Anticoagulantes/administração & dosagem , Fibrilação Atrial/complicações , Tronco Braquiocefálico , Infarto Cerebral/etiologia , Embolia/tratamento farmacológico , Embolia/etiologia , Heparina/administração & dosagem , Infarto da Artéria Cerebral Média/tratamento farmacológico , Infarto da Artéria Cerebral Média/etiologia , Varfarina/administração & dosagem , Idoso de 80 Anos ou mais , Tronco Braquiocefálico/diagnóstico por imagem , Infarto Cerebral/diagnóstico por imagem , Quimioterapia Combinada , Embolia/diagnóstico por imagem , Feminino , Humanos , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Angiografia por Ressonância Magnética , Imagem por Ressonância Magnética , Resultado do Tratamento
10.
Inorg Chem ; 56(1): 138-146, 2017 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-27976888

RESUMO

Magnetic properties of dinuclear nickel(II) complex [Ni2(sym-hmp)2](BPh4)2·3.5DMF·0.5(2-PrOH) (1), where (sym-hmp)- is 2,6-bis[(2-hydroxyethyl)methylaminomethyl]-4-methylphenolate anion and DMF indicates dimethylformamide, were investigated using high-frequency and -field electron paramagnetic resonance (HFEPR). To magnetically characterize the mononuclear nickel(II) species forming the dimer, its two dinuclear zinc(II) analogues, [Zn2(sym-hmp)2](BPh4)2·3.5DMF·0.5(2-PrOH) (2) and [Zn2(sym-hmp)2](BPh4)2·2acetone·2H2O (2'), were prepared. One of them (2') was structurally characterized by X-ray diffractometry and doped with 5% mol nickel(II) ions to prepare a mixed crystal 3. From the HFEPR results on complex 1 obtained at 40 K, the spin Hamiltonian parameters of the first excited spin state (S = 1) of the dimer were accurately determined as |D1| = 9.99(2) cm-1, |E1| = 1.62(1) cm-1, and g1 = [2.25(1), 2.19(2), 2.27(2)], and for the second excited spin state (S = 2) at 150 K estimated as |D2| ≈ 3.5 cm-1. From these numbers, the single-ion zero-field splitting (ZFS) parameter of the Ni(II) ions forming the dimer was estimated as |DNi| ≈ 10-10.5 cm-1. The HFEPR spectra of 3 yielded directly the single-ion parameters for DNi = +10.1 cm-1, |ENi| = 3.1 cm-1, and giso = 2.2. On the basis of the HFEPR results, the previously obtained magnetic data (Sakiyama, H.; Tone, K.; Yamasaki, M.; Mikuriya, M. Inorg. Chim. Acta 2011, 365, 183) were reanalyzed, and the isotropic interaction parameter between the Ni(II) ions was determined as J = -70 cm-1 (Hex = -J SA·SB). Finally, density functional theory calculations yielded the J value of -90 cm-1 in a qualitative agreement with the experiment.

11.
Chemistry ; 22(2): 724-35, 2016 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-26728231

RESUMO

Polarized neutron diffraction (PND) experiments were carried out at low temperature to characterize with high precision the local magnetic anisotropy in two paramagnetic high-spin cobalt(II) complexes, namely [Co(II) (dmf)6 ](BPh4 )2 (1) and [Co(II) 2 (sym-hmp)2 ](BPh4 )2 (2), in which dmf=N,N-dimethylformamide; sym-hmp=2,6-bis[(2-hydroxyethyl)methylaminomethyl]-4-methylphenolate, and BPh4 (-) =tetraphenylborate. This allowed a unique and direct determination of the local magnetic susceptibility tensor on each individual Co(II) site. In compound 1, this approach reveals the correlation between the single-ion easy magnetization direction and a trigonal elongation axis of the Co(II) coordination octahedron. In exchange-coupled dimer 2, the determination of the individual Co(II) magnetic susceptibility tensors provides a clear outlook of how the local magnetic properties on both Co(II) sites deviate from the single-ion behavior because of antiferromagnetic exchange coupling.

12.
Dalton Trans ; 44(30): 13439-43, 2015 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-26150171

RESUMO

A large up-field shift (-763 ppm) has been observed for the carboxyl carbons of the dichlorido complex TBA[Ru(2)(O(2)CCH(3))(4)Cl(2)] (TBA(+) = tetra(n-butyl)ammonium cation) in the (13)C NMR spectrum (CD(2)Cl(2) at 25 °C). The DFT calculations showed spin delocalization from the paramagnetic Ru(2)(5+) core to the ligands, in agreement with the large up-field shift.

13.
Dalton Trans ; 43(46): 17265-73, 2014 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-25310496

RESUMO

Two isoreticular metal-organic frameworks with chemical formulae [Cu(L)(4,4'-bipy)(H2O)]n 1.5nCH3CN (1) and [Cu(L)(4,4'-bipy)(H2O)]n·4nH2O (2) (H2L = diphenylmethane-4,4'-dicarboxylic acid) were synthesized and structurally characterized. They show the CdSO4 (6(5) 8) net and have an obvious 1D channel that is spread along the crystallographic c axis. More importantly, 1 shows high selectivity for H2 over N2 and CO2 at low pressure, which could be confirmed via computational calculations using the Connolly algorithm to reveal the size and shape of accessible voids. The incorporation of the drug 5-fluorouracil (5-FU) into the desolvated 1 was around 27.5 wt% per gram of the dehydrated 1. 5-FU is released in a highly controlled and progressive fashion with 61% of the drug released after 95 hours. In addition, we have applied molecular docking calculations to investigate the preferred conformation of 5-FU molecules upon binding to MOF 1. These calculations provide a structural basis to explain the 5-FU release from MOF 1.


Assuntos
Compostos de Cádmio/química , Simulação por Computador , Sistemas de Liberação de Medicamentos , Compostos Organometálicos/química , Sulfatos/química , Adsorção , Cristalografia por Raios X , Gases/química , Modelos Moleculares , Estereoisomerismo
14.
Dalton Trans ; 43(39): 14542-5, 2014 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-25154808

RESUMO

Here we report a versatile magnetic susceptibility equation for tetranuclear octahedral high-spin cobalt(ii) complexes and a magnetic analysis for a tetranuclear defect cubane cobalt(ii) complex based on this equation. We concluded that the interaction is essentially ferromagnetic despite the decrease in the χT product on cooling from 300 K, and the decrease is due to the spin-orbit coupling.

15.
Inorg Chem ; 51(9): 4903-5, 2012 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-22519688

RESUMO

The syntheses and structural properties of three dinuclear complexes [L(3)Co(µ(2)-O(2)P(Bn)(2))(3)CoL'][L"] [one ionic L(3) = py(3), L' = py, L" = ClO(4)(-) (1) and two molecular L(3) = py(3), L' = Cl (2) and L(3) = py, µ(2)-NO(3)(-), L' = py (3)] are reported. Complexes feature octahedral Co(II) sites bridged by three dibenzylphosphinate ligands to a tetrahedrally ligated Co(II) site, with the remaining coordination sites occupied by py, nitrato, and Cl ligands. The Co-Co distances are 4.248 Å at 291 K and 4.265 Å at 100 K for 1 and 4.278 and 4.0313(7) Å for 2 and 3, respectively at 100 K. A fit of the low-temperature magnetic susceptibility data was derived for complex 1 with g = 2.25, TIP = 700 × 10(-6) cm(3) mol (-1), λ = -173 cm(-1), κ = 0.93, ν = -3.9, Δ = 630 cm(-1), J = 0.15 cm(-1), and θ = -1.8 resulting in R(χ(M)) = 2.5 × 10(-5) and R(χ(M)T) = 5.8 × 10(-5).

16.
Acta Crystallogr B ; 67(Pt 4): 324-32, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21775811

RESUMO

The experimental charge-density distribution of the dinuclear cobalt(II) complex [Co(2)(sym-hmp)(2)](BPh(4))(2)·2H(2)O·2C(3)H(6)O was determined at 100 K. When decreasing the temperature, the magnetic susceptibility of this complex deviates from Curie law because of anti-ferromagnetic exchange interactions, but the susceptibility increases sharply at low temperature (< 20 K). To explain this magnetic behaviour a tilt angle between the Co-atom environments was previously theoretically predicted. The structure and experimental charge density determined in this study show a tilt angle. The calculated value, based on the 100 K experimental d-orbital model, is in agreement with the theoretical one.

17.
J Med Virol ; 80(3): 517-23, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18205215

RESUMO

Clinically apparent mumps reinfection is considered extremely rare, but several cases have been suspected of reinfection in an out-patient clinic. In this study, virological examination, virus isolation, the reverse transcription loop-mediated isothermal amplification (RT-LAMP), and IgG and IgM EIA antibodies, were examined in order to identify mumps reinfection. Patients were divided into three categories; the reinfection group comprised 29 patients with a history of natural infection, the vaccine-failure group consisted of 37 patients with an immunization history, and two patients had histories of both immunization and mumps infection. Another 25 patients were enrolled as a primary infection group. Mumps virus was isolated in 5 (17%) and the genome was detected in 12 (41%) of 29 in the reinfection group. Reinfection was confirmed in 21/28, demonstrating high avidity of IgG EIA. Mumps virus was isolated in 15 (41%) and there was a higher positivity of genome amplification in 25 (68%) of 37 patients in the vaccine-failure group. Among these, 23 were confirmed as secondary vaccine failure by high avidity IgG EIA serology. In the primary infection group, the isolation rate and genome detection rate was higher in 16 (64%) and in 18 (72%) of 25 patients, respectively. There was no significant difference in virus load among the three groups but high mumps virus load was suspected in the IgM EIA-positive group based on the shorter amplification time on RT-LAMP. Mumps virus reinfection was confirmed by RT-LAMP and an IgG avidity test and was not a rare event.


Assuntos
Anticorpos Antivirais/sangue , Vírus da Caxumba/isolamento & purificação , Caxumba/diagnóstico , Técnicas de Amplificação de Ácido Nucleico/métodos , Anticorpos Antivirais/imunologia , Genoma Viral , Genótipo , Humanos , Caxumba/imunologia , Caxumba/virologia , Vacina contra Caxumba/imunologia , Vírus da Caxumba/genética , Vírus da Caxumba/imunologia , Vírus da Caxumba/fisiologia , Recidiva , Carga Viral
18.
Dalton Trans ; (21): 2145-9, 2007 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-17514335

RESUMO

The hydrothermal reaction of 2-pyrimidine-carboxamide, CoCl2.6H(2)O and K3[Co(CN)6] affords a novel mixed-valence Co(II)/Co(III) 3D complex K[Co3(CN)6(ox)(H(2)O)2].H2O, which contains cyano-bridged Co(7) defective cubanes connected by oxalate and cyanide bridging groups and behaves as a canted antiferromagnet with Tc = 17.5 K.

19.
Vaccine ; 25(14): 2742-7, 2007 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-16530894

RESUMO

To compare the incidence of aseptic meningitis associated with symptomatic natural mumps infection and in mumps vaccine recipients, we conducted a prospective comparative study. Consecutive samples of 1051 children with mumps were enrolled by 10 pediatricians and 21,465 vaccine recipients by 143 pediatric primary care practitioners, from January 1, 2000 to January 1, 2003. Parents used a daily diary to record symptoms during the period of illness (15 days) or 30-day period following immunization. Mumps infection was confirmed by virus isolation and/or detection of mumps virus genome in salivary and CSF samples. The incidence of aseptic meningitis was 13/1051 (1.24%) in patients with symptomatic natural mumps infection and was estimated to be 0.7-1.1% of overall infection in considering asymptomatic infection, and 10/21,465 (0.05%) in vaccine recipients. Although aseptic meningitis is a clear side effect of the mumps vaccine, the incidence is considerably lower than among those with symptomatic natural infection. Our results provide an informative data for consideration to resume mumps vaccine as a part of routine immunization schedule for Japanese children.


Assuntos
Meningite Asséptica/epidemiologia , Vacina contra Caxumba/efeitos adversos , Caxumba/complicações , Adolescente , Criança , Pré-Escolar , Feminino , Hospitalização , Humanos , Incidência , Lactente , Japão/epidemiologia , Masculino , Estudos Prospectivos
20.
Dalton Trans ; (2): 249-56, 2007 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-17180193

RESUMO

The isomorphous coordination polymers {micro-Au(CN)(2)](2)[(M(NH(3))(2))(2)(mu-bpym)]}[Au(CN)(2)](2) (M = Co(II) (1), Ni(II) (2), Cu(II) (3)) have been prepared from the reaction of 2 equiv. M(NO(3))(2) x nH(2)O (M = Cu(II), n = 3; M = Ni(II) and Co(II), n = 6) with 1 equiv. of bipyrimidine (bpym) in aqueous ammonia and then with an aqueous solution containing 1 equiv. of K[Au(CN)(2)]. The structures of these complexes are made of bpym bridged centrosymmetric dinuclear [M(NH(3))(2)(mu-bpym)M(NH(3))(2)] units connected by [Au(CN)(2)](-) anions to four other dinuclear units giving rise to a cationic 2D (4,4) rectangular grid network, its charge being balanced by two non-coordinated [Au(CN)(2)](-). The layers are stacked in such a way that the ammonia coordinated molecules are interdigitated and aligned above and below one sheet with cavities in neighbouring sheets, giving rise to an ABAB[dot dot dot] repeat pattern of layers. Gold atoms of bridging and non-bridging dicyanoaurate anions are involved in short aurophilic interactions (Au1-Au2 distances in the range 3.12-3.14 Angstrom), leading to a chain of gold atoms running along the a direction. Neighbouring gold chains are further connected by weaker aurophilic interactions (Au1-Au1 distances in the range 3.43-3.49 Angstrom), affording a honeycomb-like 2D network of gold atoms. The (4,4) rectangular sheets and (6,3) honeycomb sheets share the Au2 atoms, leading to a unique 3D network. Magnetic measurements clearly show the existence of antiferromagnetic exchange coupling between the metal ions with susceptibility maxima at 17 K (1), 22 K (2), and 17 K (3). The data of 1 were analyzed through a full Hamiltonian involving spin-orbit coupling, axial distortion, Zeeman interactions and magnetic exchange coupling between Co(II), and the best fit gives J = -9.23 cm(-1), kappa = 0.99, lambda = -142 cm(-1), Delta = -562 cm(-1). For 2 and 3, magnetic data were fitted to the theoretical equations derived from the isotropic Hamiltonian: H = -JS(1)S(2). The best fit parameters were g = 2.050(1), J = -17.51(1) and P = 0.01(2) for 2 and g = 2.068(5), J = -20.07(8) and P = 0.015(4) for 3, respectively (P takes into account the amount of paramagnetic impurity). In order to explain the weak magnetic interaction between copper(II) ions mediated by the bipyrimidine bridging ligand in 3, we have carried out electronic structure calculations based on the density functional theory (DFT).

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