Search results for "imide"
showing 10 items of 298 documents
Study of the complex formation between the [Cu(bpca)]+ secondary building unit and the aromatic N donors 2,3,5,6-tetra(2-pyridyl)pyrazine (tppz) and …
2017
Two new complexes of the formula [{Cu(bpca)}2(μ-tppz)](NO3)2·5H2O (1) and [Cu(bpca)(H2O)(ClO4)(μ-bpp)Cu(bpca)(H2O)2]ClO4·H2O (2) [tppz = 2,3,5,6-tetra(2-pyridyl)pyrazine and bpp = 1,3-bis(4-pyridyl)propane] have been prepared by the reaction of the [Cu(bpca)]+ [Hbpca = bis(2-pyridylcarbonyl)imide] building block and the tppz and bpp N donors. An unusual coordination mode of the tppz ligand was observed in 1, which functions as a bis(bidentate) ligand to two copper(II) atoms each coordinated to a nitrogen atom of the pyrazine moiety and a pyridyl nitrogen atom. This compound presents a layered structure of alternating anionic (ca. 1.6 A) and cationic (ca. 10 A) slices, providing the opportun…
Mechanical and thermal behaviour of networks with “flexible” and “rigid” chains
1996
“Rigid-rod” telechelics were synthesized via repetitive Diels-Alder reaction of biscyclohexadienes and bis(1,2,4-triazoline-3,5-diones). The bistriazolinediones were used in slight excess. The rigidity of the building blocks and the molecular weight were varied. Various amounts of these reactive telechelics are used to crosslink cis-1,4-polybutadiene. The mechanical and the thermal properties of these two-component networks were investigated by stress-strain, differential scanning calorimetry and dynamic-mechanical measurements. The occurrence of microphase separation between the “rigid” and the “flexible” components is discussed to explain the properties of these materials.
Site-specific targeting of enterovirus capsid by functionalized monodisperse gold nanoclusters
2014
Development of precise protocols for accurate site-specific conjugation of monodisperse inorganic nanoparticles to biological material is one of the challenges in contemporary bionanoscience and nanomedicine. We report here a successful site-specific covalent conjugation of functionalized atomically monodisperse gold clusters with 1.5-nm metal cores to viral surfaces. Water-soluble Au102(para-mercaptobenzoic acid)44 clusters, functionalized by maleimide linkers to target cysteines of viral capsid proteins, were synthesized and conjugated to enteroviruses echovirus 1 and coxsackievirus B3. Quantitative analysis of transmission electron microscopy images and the known virus structures showed …
Electrochemical study of copper chloride complexes in the RTIL 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide
2013
The electrochemistry of copper(I) and copper(II) chloride complexes in the RTIL 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, BMPTf2N, has been studied with constant current electrolysis and cyclic staircase voltammetry at temperatures between 21.0 and 96.0 °C and in different concentrations of chloride. The chloride concentration was controlled by addition of 1-butyl-1-methylpyrrolidinium chloride, BMPCl. An important finding is the evidence of a three-coordinated complex, Cu(I)Cl32− which has not been found in organic chloroaluminates without a significant increase in temperature. Two Cu(I) species were found at molar ratios of [Cl−]/[Cu] < 4. The kinetic parameters for…
Poly(naphthalenediimidequaterthiophene):Poly(hexyilthiophene) Heterojunctions. Efficient Polymer-to-Polymer Electron Transfer Interfaces
2013
Organic thin films solar cells and plastic solar cells [1] have attracted the attention of the scientific community especially as regards the performance of new conjugated polymers including their interfaces [2-4]. In this work, poly(naphthalenediimidequaterthiophene) (PNDIT4) and poly(hexyilthiophene) (P3HT) have been employed, for the first time, for engineering planar and bulk heterojunctions by the synergetic use of two techniques: electropolymerization and layer by layer deposition. Electropolymerization has been used for obtaining PNDIT4 thin films on transparent ITO/PET electrodes, starting from the synthesized monomer. Inverse Langmuir-Schaefer technique has been employed for deposi…
Anti-PR-3 antibodies induce endothelial IL-8 release
1999
Background It has been shown that interaction of anti-PR-3 antibodies with human endothelial cells (EC) leads to an activation of EC in vitro, i.e. induction of adhesion molecules like E-selectin, VCAM-1 and tissue factor. The aim of this study was to investigate the effect of anti-PR-3 antibodies on endothelial IL-8 expression. Materials and methods EC were cultured in 96-well plates and stimulated with TNF-α and IL-1β for 1 h to induce membrane expression of endothelial PR-3. Anti-PR-3 antibodies were purified from sera from patients with clinically active Wegener's granulomatosis. Purified anti-Ro, anti-centromere, anti-dsDNA antibodies and a monoclonal anti-PR-3 antibody (WGM2) served a…
Involvement of carboxyl groups in chloride transport and reversible DIDS binding to band 3 protein in human erythrocytes
2011
AbstractNoncovalent DIDS binding to Band 3 (AE1) protein in human erythrocyte membranes, modified by non-penetrating, water soluble 1-ethyl-3-(4-azonia-4,4-dimethylpentyl)-carbodiimide iodide (EAC), was studied at 0°C in the presence of 165 mM KCl. Under experimental conditions applied up to (48 ± 5) % of irreversible chloride self-exchange inhibition was observed. The apparent dissociation constant, KD, for “DIDS-Band 3” complex, determined from the chloride transport experiments, was (34 ± 3) nM and (80 ± 12) nM for control and EAC-treated resealed ghosts, respectively. The inhibition constant, Ki, for DIDS was (35 ± 6) nM and (60 ± 8) nM in control and EAC-treated ghosts, respectively. T…
Simultaneous Separation of Antioxidants and Carbohydrates From Food Wastes Using Aqueous Biphasic Systems Formed by Cholinium-Derived Ionic Liquids
2019
project CICECO-Aveiro Institute of Materials, UID/CTM/50011/2019. Associate Laboratory for Green Chemistry-LAQV, FCT Ref. UID/QUI/50006/2019. POCI-01-0145-FEDER-016403. Investigator FCT project IF/00621/2015. Programa Mais Centro under project CENTRO-07-ST24-FEDER-002008. COMPETE: PEst-C/SAU/UI0709/2011. The food industry produces significant amounts of waste, many of them rich in valuable compounds that could be recovered and reused in the framework of circular economy. The development of sustainable and cost-effective technologies to recover these value added compounds will contribute to a significant decrease of the environmental footprint and economic burden of this industry sector. Acc…
Retention-pH profiles of acids and bases in hydrophilic interaction liquid chromatography
2018
Abstract The high proportion of acetonitrile used in many HILIC mobile phases significantly changes the acid-base properties of pH buffers and analytes foreseen from available data in water. In this paper, the recommended stability pH range for chromatographic columns is examined with various acetonitrile/water mixtures, resulting in a significant broadening in the operational pH window with the content of organic solvent. Additionally, the challenge of buffer selection in HILIC is also addressed. Commonly used ammonium acetate shrinks its pH buffering range in acetonitrile-rich mobile phases due to variations in the dissociation constants of the buffer constituents (acetic acid and ammoniu…