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Showing 1 to 20 of 94 for “"Pyridinium"”.
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Preparation of Pyridinium and Diaminocarbonium Barbituric Acid Ylides
… charge separation inside the molecule. 5-Ylide-pyridinium-methyl barbituric acid derivatives were investigated with the isolation of 4-dimethylamino-1-(2,4,6-trioxohexahydro- pyrimidin-5-ylide-methyl)-pyridinium as well as its corresponding 1,3- dimethylbarbituric acid derivative with …
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Flotation of sulfide minerals with alkyl pyridinium salts
Long chain alkyl pyridinium salts have been used as collectors for the flotation of chalcopyrite and copper-activated sphalerite. For the ores tested in this study, these reagents have demonstrated improved selectivity and recovery in comparison to conventional xanthates. The best flotation …
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Study of organic reactions in pyridinium-based ionic liquids
… information is available on the application of pyridinium-based ionic liquids. In this study, two different ionic liquids, 1 -ethyl-pyridinium tetrafluoroborate ([EtPy]^+[BF_4]^-) and 1 -ethyl-pyridinium trifluoroacetate ([EtPy]^+[CF_3COO]^-) have been investigated. Compared to previous reports, …
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Poly(pyridinium salt)s exhibiting liquid-crystalline and light-emitting properties
… on the synthesis and characterization of poly(pyridinium salt)s containing tosylate and triflimide counterions that possess both liquid-crystalline properties as well as light emitting properties. Both the solution-state and solid-state emission behavior of these synthesized materials were …
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Spectral and Spatial Heterogeneity in Molecular Assemblies of Amino Styryl Pyridinium Dyes
The aggregation properties of amino styryl pyridinium dyes (ASPs) greatly reduce their ability to be incorporated into molecular scale devices that would utilize their large molecular hyperpolarizabilities, in such areas as molecular optics, opto-electronics, or telecommunications. This work …
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Supramolecular effects in pyridinium compounds and their application towards practical redox flow battery systems
… Such capabilities are demonstrated for pyridinium-based systems and *operando* spectroscopic techniques are used to gain fundamental insights into structure and mechanisms. From such insights, methods are unlocked to both harness and suppress supramolecular effects towards regimes of …
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A kinetic study of the chromium (VI) - arsenic (III) reaction in pyridine-pyridinium buffer solutions containing oxalate
… by chromium (VI) has been studied in pyridine - pyridinium buffers with and without added oxalate ion. The rate law at pH 4.6 for the reactions without oxalate is best described as - d[Cr(VI)]/dt = (0.535 [As(III)]² [Cr(VI)])/(1+187 [As(III)]) This is in accord with the general mechanism for …
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Effects of type-I collagen fractional composition and pyridinium crosslink content on cortical bone strength in the human femur
… the human femur, (2) the mature, non-reducible pyridinium crosslink content of this bone, and (3) assessed the potential relationships of these findings to fracture resistance and to the age and sex of the bone donor. It was hypothesized that higher amounts of type-I collagen and pyridinium …
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HYPERVALENT IODINE-MEDIATED HETEROCYCLIC GROUP TRANSFER REACTIONS TO OXIDATIVE OLEFIN DIFUNCTIONALIZATION
The development of new strategies to access pyridinium salts are highly sought out due to their advantageous structures, which have diverse applications across materials science, biological processes, and organic synthesis. As synthetic intermediates, these scaffolds can be used as precursors to …
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Studies on the metabolic bioactivation of haloperidol (HP) and its tetrahydropyridine dehydration product
… undergo metabolic bioactivation to neurotoxic pyridinium metabolites. In vitro metabolic studies have demonstrated that human monoamine oxidase A and cytochrome P450 3A4 are capable of catalyzing the oxidation of HPTP and/or HP to the toxic HP pyridinium metabolite {4-(4-chlorophenyl)-1-[4- …
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Metabolic Studies on 1-Cyclopropyl-4-phenyl-1,2,3,6-tetrahydropyridinyl Derivatives by HPLC and LC-ESI/MS
… to generate the neurotoxic 1-methyl-4-phenylpyridinium species (MPP+) is well documented. The N-cyclopropyl analog (CPTP) of MPTP is a mechanism based inactivator of MAO-B which presumably is processed by a single electron transfer (SET) pathway to generate a bioalkylating species. These …
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A PROPOSED NEW INTERNAL STANDARD FOR FREE, GLYCOSYLATED AND TOTAL PYRIDINIUM CROSSLINKS QUANTIFICATION IN HEALTHY WOMEN AND CHILDREN URINE: VALIDATION OF AN HPLC-FLUORESCENCE METHOD
… purpose, the changing in urine concentrations of pyridinium crosslinks is usually measured. Pyridinium crosslinks are generally referred to the chemical compounds pyridinoline (Pyr) and deoxypyridinoline (D-Pyr), both considered specific markers of skeletal collagen degradation. They are released …
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Bicyclic Heterocyclic Systems Derived from 1, 3, 4-Trisubstituted Pyridines
… are prepared by reduction of the appropriate pyridinium iodides with sodium borohydride. The reduction of 3,4-dimethoxycarbonyl-1-methyl pyridinium iodide by sodium borohydride gives the expected tetrahydro derivative and 3,4-dimethoxycarbonyl-1-methylpyrid-6-one; the pyridone was also …
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New Aspects of the Chemistry of Quaternary Addition Reagents for the Electrocrystallisation of Zinc.
The introduction of quaternary pyridinium derivatives as brightening agents for the electrodeposition of zinc from alkaline electrolytes is one of the significant recent advances in this field. This work describes the brightening effect of quaternary pyridinium derivatives, with differences in …
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Design of Lipid and Polymeric Carriers for Nucleic Acid Delivery
… In Chapter 3, we synthesized a series of pyridinium lipids which contain a heterocyclic ring and a nitrogen atom. The structure–activity relationship (SAR) and formulation of corresponding cationic liposomes were studied for gene and siRNA delivery. The pyridinium lipids were mixed with a …
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Functionalization of nanoclays through exchange reactions
… of clays modified in our group with smaller MW pyridinium and imidazolium based cations. 10 wt% of interchanged cation was found under selected time/temperature treatment conditions. Clays modified with the long chain phosphonium based ILs showed excellent dispersion in a PP matrix, by contrast …
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