The Experts below are selected from a list of 153 Experts worldwide ranked by ideXlab platform
Teresa Tavares - One of the best experts on this subject based on the ideXlab platform.
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Immobilization of Fe(III) complexes of Pyridazine Derivatives prepared from biosorbents supported on zeolites
Microporous and Mesoporous Materials, 2008Co-Authors: Hugo Figueiredo, Bruna Silva, M. Manuela M. Raposo, António M. Fonseca, Isabel C. Neves, Cristina Quintelas, Teresa TavaresAbstract:Immobilization of Fe(III) complexes of Pyridazine Derivatives was achieved in NaY zeolite, loaded with iron through the action of a robust biosorption mediator consisting of a bacterial biofilm, Arthrobacter viscosus, supported on the zeolite. The objective of this study is the preparation and characterization of new catalytic materials to be used in oxidation reactions under mild conditions. The biosorption of Fe(III) ions was performed starting from aqueous solutions with low concentrations of iron and the highest values of biosorption efficiency for Fe(III) were reached at the beginning of the contact period with the sorbents. The Fe(III) biosorption process was compared with the one of Cr(III) under the same experimental conditions, as this latter case has been well characterized. The sample used in the immobilization of Fe(III) complexes of Pyridazine Derivatives was prepared from an aqueous solution of 100.0 mgFe/L, without the competing effect of other metals. Fe(III) is retained in the zeolite by ion exchange and coordination with two different Pyridazine Derivative ligands, 3-ethoxy-6-chloroPyridazine (A) and 3-piperidino-6-chloroPyridazine (B). The resulting materials were fully characterized by different spectroscopic methods (EPR, FTIR and UV–vis), chemical analysis (CA), surface analysis (XRD and SEM) and thermogravimetric (TGA) analysis and the results indicated that the Fe(III) complexes of Pyridazine Derivatives were effectively immobilized in NaY inside the supercages, without any modifications of the morphology and structure of the zeolite. The EPR spectra of the Fe(III) complexes in Y zeolite show signals at g = 4.3 and 2.3, attributed to Fe(III) species coordinated to Pyridazine Derivative ligands.GIQIMO, Santiago de Compostela UniversityDepartment of Earth Sciences of the University of MinhoFundação para a Ciência e a Tecnologia (FCT) (FCT)
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Immobilization of Fe(III) complexes of Pyridazine Derivatives prepared from biosorbents supported on zeolites
Microporous and Mesoporous Materials, 2007Co-Authors: Hugo Figueiredo, Bruna Silva, M. Manuela M. Raposo, António M. Fonseca, Isabel C. Neves, Cristina Quintelas, Teresa TavaresAbstract:Abstract Immobilization of Fe(III) complexes of Pyridazine Derivatives was achieved in NaY zeolite, loaded with iron through the action of a robust biosorption mediator consisting of a bacterial biofilm, Arthrobacter viscosus, supported on the zeolite. The objective of this study is the preparation and characterization of new catalytic materials to be used in oxidation reactions under mild conditions. The biosorption of Fe(III) ions was performed starting from aqueous solutions with low concentrations of iron and the highest values of biosorption efficiency for Fe(III) were reached at the beginning of the contact period with the sorbents. The Fe(III) biosorption process was compared with the one of Cr(III) under the same experimental conditions, as this latter case has been well characterized. The sample used in the immobilization of Fe(III) complexes of Pyridazine Derivatives was prepared from an aqueous solution of 100.0 mgFe/L, without the competing effect of other metals. Fe(III) is retained in the zeolite by ion exchange and coordination with two different Pyridazine Derivative ligands, 3-ethoxy-6-chloroPyridazine (A) and 3-piperidino-6-chloroPyridazine (B). The resulting materials were fully characterized by different spectroscopic methods (EPR, FTIR and UV–vis), chemical analysis (CA), surface analysis (XRD and SEM) and thermogravimetric (TGA) analysis and the results indicated that the Fe(III) complexes of Pyridazine Derivatives were effectively immobilized in NaY inside the supercages, without any modifications of the morphology and structure of the zeolite. The EPR spectra of the Fe(III) complexes in Y zeolite show signals at g = 4.3 and 2.3, attributed to Fe(III) species coordinated to Pyridazine Derivative ligands.
Yulan Chen - One of the best experts on this subject based on the ideXlab platform.
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acid induced multicolor fluorescence of Pyridazine Derivative
ACS Applied Materials & Interfaces, 2018Co-Authors: Yuan Yuan, Yulan ChenAbstract:Smart luminescent materials that are responsive to external stimuli have received considerable attention. Here, we report a new D-A type 1,2-pyridiazine Derivative (3,4,5,6-tetrakis(4-methoxyphenyl)Pyridazine (TPP)) exhibiting turn-on fluorescence upon acid exposure both in solution and in the solid state. The protonation of the 1,2-pyridiazine ring caused a variation in the emission colors of the acidification species from blue (406 nm) to orange-red (630 nm) with a huge Δλem (224 nm). As a result, a synthetic rainbow of emission in solution could be achieved from one single molecule, and white photoluminescence was readily tuned by controlled protonation. A trifluoroacetic acid (TFA)-sensor film made from TPP was demonstrated as a TFA-sensitive surface with high sensitivity and reversibility. On the basis of these findings, we constructed a solid-state TPP film with a photoacid generator and demonstrated data encryption and decryption via a cascade protonation reaction that was well controlled by UV light.
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Acid-Induced Multicolor Fluorescence of Pyridazine Derivative
2017Co-Authors: Yuan Yuan, Yulan ChenAbstract:Smart luminescent materials that are responsive to external stimuli have received considerable attention. Here, we report a new D–A type 1,2-pyridiazine Derivative (3,4,5,6-tetrakis(4-methoxyphenyl)Pyridazine (TPP)) exhibiting turn-on fluorescence upon acid exposure both in solution and in the solid state. The protonation of the 1,2-pyridiazine ring caused a variation in the emission colors of the acidification species from blue (406 nm) to orange-red (630 nm) with a huge Δλem (224 nm). As a result, a synthetic rainbow of emission in solution could be achieved from one single molecule, and white photoluminescence was readily tuned by controlled protonation. A trifluoroacetic acid (TFA)-sensor film made from TPP was demonstrated as a TFA-sensitive surface with high sensitivity and reversibility. On the basis of these findings, we constructed a solid-state TPP film with a photoacid generator and demonstrated data encryption and decryption via a cascade protonation reaction that was well controlled by UV light
Duckett, Simon B. - One of the best experts on this subject based on the ideXlab platform.
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A simple and cost-efficient technique to generate hyperpolarized long-lived 15N-15N nuclear spin order in a diazine by signal amplification by reversible exchange
American Institute of Physics Inc., 2020Co-Authors: Roy S. S., Rayner P J, Burns M J, Duckett, Simon B.Abstract:Signal Amplification by Reversible Exchange (SABRE) is an inexpensive and simple hyperpolarization technique that is capable of boosting nuclear magnetic resonance sensitivity by several orders of magnitude. It utilizes the reversible binding of para-hydrogen, as hydride ligands, and a substrate of interest to a metal catalyst to allow for polarization transfer from para-hydrogen into substrate nuclear spins. While the resulting nuclear spin populations can be dramatically larger than those normally created, their lifetime sets a strict upper limit on the experimental timeframe. Consequently, short nuclear spin lifetimes are a challenge for hyperpolarized metabolic imaging. In this report, we demonstrate how both hyperpolarization and long nuclear spin lifetime can be simultaneously achieved in nitrogen-15 containing Derivatives of Pyridazine and phthalazine by SABRE. These substrates were chosen to reflect two distinct classes of 15N2-coupled species that differ according to their chemical symmetry and thereby achieve different nuclear spin lifetimes. The Pyridazine Derivative proves to exhibit a signal lifetime of �2.5 min and can be produced with a signal enhancement of �2700. In contrast, while the phthalazine Derivative yields a superior 15 000-fold 15N signal enhancement at 11.7 T, it has a much shorter signal lifetime
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A Simple and Cost-efficient Technique to Generate Hyperpolarized Long-lived 15N-15N Nuclear Spin Order in a Diazine by Signal Amplification by Reversible Exchange
2020Co-Authors: Roy S. S., Rayner, Peter John, Burns Michael, Duckett, Simon B.Abstract:Signal Amplification by Reversible Exchange (SABRE) is an inexpensive and simple hyperpolarization technique and is capable of boosting Nuclear Magnetic Resonance (NMR) sensitivity by several orders of magnitude. It utilizes the reversible binding of para-hydrogen as hydride ligands and a substrate of interest to a metal catalyst to allow polarization transfer from para-hydrogen to the substrate nuclear spins. The nuclear spin lifetime of the created magnetization sets a strict upper limit on experimental timeframe. Short nuclear spin lifetimes are therefore a challenge for hyperpolarized metabolic imaging prospects. In this report we demonstrate how hyperpolarization and long nuclear spin lifetime can simultaneously be achieved in nitrogen-15 containing Pyridazine and phthalazine Derivatives by SABRE. These reflect two distinct classes of 15N2-coupled species with respect to their chemical symmetry and thus show different nuclear spin lifetime with the Pyridazine Derivative having a singlet state lifetime of ca. 2.5 minutes, produced with a signal enhancement of ca. 2,700. In contrast the phthalazine Derivative yields a superior 15,000-fold enhancement at 11.7 T but has a much shorter singlet lifetime
Dan Gao - One of the best experts on this subject based on the ideXlab platform.
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selective synthesis in microdroplets of 2 phenyl 2 3 dihydrophthalazine 1 4 dione from phenyl hydrazine with phthalic anhydride or phthalic acid
Chemistry: A European Journal, 2019Co-Authors: Dan Gao, Feng Jin, Xin Yan, Richard N ZareAbstract:Pyridazine Derivatives are privileged structures because of their potential biological and optical properties. Traditional synthetic methods usually require acid or base as a catalyst under reflux conditions with reaction times ranging from hours to a few days or require microwave assistance to induce the reaction. Herein, this work presents the accelerated synthesis of a Pyridazine Derivative, 2-phenyl-2,3-dihydrophthalazine-1,4-dione (PDHP), in electrosprayed microdroplets containing an equimolar mixture of phenyl hydrazine and phthalic anhydride or phthalic acid. This reaction occurred on the submillisecond timescale with good yield (over 90 % with the choice of solvent) without using an external catalyst at room temperature. In sharp contrast to the bulk reaction of obtaining a mixture of two products, the reaction in confined microdroplets yields only the important six-membered heterocyclic product PDHP. Results indicated that surface reactions in microdroplets with low pH values cause selectivity, acceleration, and high yields.
Hugo Figueiredo - One of the best experts on this subject based on the ideXlab platform.
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Immobilization of Fe(III) complexes of Pyridazine Derivatives prepared from biosorbents supported on zeolites
Microporous and Mesoporous Materials, 2008Co-Authors: Hugo Figueiredo, Bruna Silva, M. Manuela M. Raposo, António M. Fonseca, Isabel C. Neves, Cristina Quintelas, Teresa TavaresAbstract:Immobilization of Fe(III) complexes of Pyridazine Derivatives was achieved in NaY zeolite, loaded with iron through the action of a robust biosorption mediator consisting of a bacterial biofilm, Arthrobacter viscosus, supported on the zeolite. The objective of this study is the preparation and characterization of new catalytic materials to be used in oxidation reactions under mild conditions. The biosorption of Fe(III) ions was performed starting from aqueous solutions with low concentrations of iron and the highest values of biosorption efficiency for Fe(III) were reached at the beginning of the contact period with the sorbents. The Fe(III) biosorption process was compared with the one of Cr(III) under the same experimental conditions, as this latter case has been well characterized. The sample used in the immobilization of Fe(III) complexes of Pyridazine Derivatives was prepared from an aqueous solution of 100.0 mgFe/L, without the competing effect of other metals. Fe(III) is retained in the zeolite by ion exchange and coordination with two different Pyridazine Derivative ligands, 3-ethoxy-6-chloroPyridazine (A) and 3-piperidino-6-chloroPyridazine (B). The resulting materials were fully characterized by different spectroscopic methods (EPR, FTIR and UV–vis), chemical analysis (CA), surface analysis (XRD and SEM) and thermogravimetric (TGA) analysis and the results indicated that the Fe(III) complexes of Pyridazine Derivatives were effectively immobilized in NaY inside the supercages, without any modifications of the morphology and structure of the zeolite. The EPR spectra of the Fe(III) complexes in Y zeolite show signals at g = 4.3 and 2.3, attributed to Fe(III) species coordinated to Pyridazine Derivative ligands.GIQIMO, Santiago de Compostela UniversityDepartment of Earth Sciences of the University of MinhoFundação para a Ciência e a Tecnologia (FCT) (FCT)
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Immobilization of Fe(III) complexes of Pyridazine Derivatives prepared from biosorbents supported on zeolites
Microporous and Mesoporous Materials, 2007Co-Authors: Hugo Figueiredo, Bruna Silva, M. Manuela M. Raposo, António M. Fonseca, Isabel C. Neves, Cristina Quintelas, Teresa TavaresAbstract:Abstract Immobilization of Fe(III) complexes of Pyridazine Derivatives was achieved in NaY zeolite, loaded with iron through the action of a robust biosorption mediator consisting of a bacterial biofilm, Arthrobacter viscosus, supported on the zeolite. The objective of this study is the preparation and characterization of new catalytic materials to be used in oxidation reactions under mild conditions. The biosorption of Fe(III) ions was performed starting from aqueous solutions with low concentrations of iron and the highest values of biosorption efficiency for Fe(III) were reached at the beginning of the contact period with the sorbents. The Fe(III) biosorption process was compared with the one of Cr(III) under the same experimental conditions, as this latter case has been well characterized. The sample used in the immobilization of Fe(III) complexes of Pyridazine Derivatives was prepared from an aqueous solution of 100.0 mgFe/L, without the competing effect of other metals. Fe(III) is retained in the zeolite by ion exchange and coordination with two different Pyridazine Derivative ligands, 3-ethoxy-6-chloroPyridazine (A) and 3-piperidino-6-chloroPyridazine (B). The resulting materials were fully characterized by different spectroscopic methods (EPR, FTIR and UV–vis), chemical analysis (CA), surface analysis (XRD and SEM) and thermogravimetric (TGA) analysis and the results indicated that the Fe(III) complexes of Pyridazine Derivatives were effectively immobilized in NaY inside the supercages, without any modifications of the morphology and structure of the zeolite. The EPR spectra of the Fe(III) complexes in Y zeolite show signals at g = 4.3 and 2.3, attributed to Fe(III) species coordinated to Pyridazine Derivative ligands.
