The Experts below are selected from a list of 114 Experts worldwide ranked by ideXlab platform
Jyh‐myng Zen - One of the best experts on this subject based on the ideXlab platform.
-
Tetracycline immobilization as Hydroquinone Derivative at dissolved oxygen reduction potential on multiwalled carbon nanotube
Journal of The Electrochemical Society, 2012Co-Authors: Annamalai Senthil Kumar, Sundaram Sornambikai, Shanmuganathan Venkatesan, Jen-lin Chang, Jyh‐myng ZenAbstract:Upon continuous potential cycling of multiwalled carbon nanotube modified electrode (GCE/MWCNT) with Tetracycline antibiotic (Tet) at −0.5 to 0.4 V vs Ag/AgCl in pH 7 phosphate buffer solution, the Tet drug gets selectively immobilized as Tet-Hydroquinone Derivative (Tet-HQ) on the GCE/MWCNT (GCE/Tet-HQ@MWCNT) and showed a specific surface confined redox peak at E1/2 =−0.24 ± 0.02 V vs Ag/AgCl. Control potential cycling experiment with o-cresol resulted to similar electrochemical characteristic too. But with p-cresol, no such surface confined redox peak was noticed. Dissolved oxygen reduction to hydrogen peroxide (as an intermediate species) at −0.45 V vs Ag/AgCl and its chemical oxidation of the surface bound Tet@MWCNT to Tet-HQ@MWCNT is proposed as a plausible mechanism. Separate ring-disk screen-printed carbon electrode assembly, where MWCNT and a H2O2 detection catalyst (nano-MnO2) modified on the ring and disk respectively, coupled with flow injection analysis showed specific current signals for oxygen reduction reaction at −0.45 V vs Ag/AgCl on the disk and subsequent H2O2 oxidation on ring at 0.8 V vs Ag/AgCl. The surface confined redox system showed highly selective electrocatalytic reduction signal to hydrogen peroxide at ∼0.22 V vs Ag/AgCl without any interference from the ascorbic acid, uric acid, cysteine and nitrite
Karl Heinz Dötz - One of the best experts on this subject based on the ideXlab platform.
-
Oxacycloalkenyliden‐Komplexe von Chrom, Molybdän und Wolfram: Synthese, Anellierung mit Alkinen und Diels‐Alder‐Reaktionen mit Dienen
Chemische Berichte, 1995Co-Authors: Jens Christoffers, Karl Heinz DötzAbstract:Reactions of Complex Ligands, LXI[1]. - Oxacycloalkenylidene Complexes of Chromium, Molybdenum, and Tungsten: Synthesis, Their Annulation with Alkynes and Diels-Alder Reaction with Dienes Lithiiated propargylic ether 1 reacts with M(CO)6 (M = Cr, Mo, W) to give the 2-oxacyclic carbene complexes 2–4 containing an α,β-double bond and a cyclic acetal structure which serves as a protected benzoyl group. Reaction of the chromium complex 2 with tolan leads to an acyl Hydroquinone Derivative 5. The tungsten complex 3 undergoes a [4 + 2] cycloaddition with cyclopentadiene to give two diastereomeric oxatricyclic carbene complexes 6 and 7 with an endo/exo selectivity of 3:1. The stereochemistry of the Diels-Alder reaction is controlled by the configuration of the acetal carbon center.
-
Novel synthesis of oxacycloalkenylidene complexes and their annulation to an acyl Hydroquinone Derivative
J. Chem. Soc. Chem. Commun., 1993Co-Authors: Jens Christoffers, Karl Heinz DötzAbstract:2-Oxacyclopentenylidene complexes of chromium and tungsten are formed in a one pot reaction from lithiated prop-2-ynylic ether and the metal carbonyl; the chromium complex undergoes annulation by tolan to give an acyl Hydroquinone skeleton.
Davood Nematollahi - One of the best experts on this subject based on the ideXlab platform.
-
Electrocatalytic determination of morphine at the surface of a carbon paste electrode spiked with a Hydroquinone Derivative and carbon nanotubes
Journal of Electroanalytical Chemistry, 2012Co-Authors: M. Reza Shishehbore, Hamid R. Zare, Davood NematollahiAbstract:Abstract This study aims at the electrochemical characterization of a novel sensor for the electrocatalytic determination of morphine (MO). The sensor is based on a carbon paste electrode spiked with 4-hydroxy-2-(triphenylphosphonio)phenolate (HTP) and multi-wall carbon nanotubes (HTP-MWCNT-CPE). The cyclic voltammetric responses of MO oxidation at the modified electrode surface at different potential scan rates show a characteristic shape typical of an EC catalytic mechanism. Cyclic voltammetry, chronoamperometry, and differential pulse voltammetry (DPV) were used to probe the characteristics of the modified electrode. The catalytic peak current obtained by DPV was linearly dependent on the MO concentration over the range 1.0–950.0 μM in two linear segments with a detection limit of 0.066 μM. The precision of DPV was found to be 3% for 15 replicate determinations of 4.0 μM of MO. For a binary mixture containing MO and acetaminophen (AC), two well-distinguished differential pulse voltammograms were obtained in the physiological pH (pH 7.0). The sensitivities of the modified electrode toward MO in the absence and presence of AC were found to be virtually the same, which refers to the fact that the electrocatalytic oxidation processes of MO are independent of AC. The modified electrode was successfully applied for the determination of MO and AC in a urine sample and pharmaceutical formulations.
Annamalai Senthil Kumar - One of the best experts on this subject based on the ideXlab platform.
-
Tetracycline immobilization as Hydroquinone Derivative at dissolved oxygen reduction potential on multiwalled carbon nanotube
Journal of The Electrochemical Society, 2012Co-Authors: Annamalai Senthil Kumar, Sundaram Sornambikai, Shanmuganathan Venkatesan, Jen-lin Chang, Jyh‐myng ZenAbstract:Upon continuous potential cycling of multiwalled carbon nanotube modified electrode (GCE/MWCNT) with Tetracycline antibiotic (Tet) at −0.5 to 0.4 V vs Ag/AgCl in pH 7 phosphate buffer solution, the Tet drug gets selectively immobilized as Tet-Hydroquinone Derivative (Tet-HQ) on the GCE/MWCNT (GCE/Tet-HQ@MWCNT) and showed a specific surface confined redox peak at E1/2 =−0.24 ± 0.02 V vs Ag/AgCl. Control potential cycling experiment with o-cresol resulted to similar electrochemical characteristic too. But with p-cresol, no such surface confined redox peak was noticed. Dissolved oxygen reduction to hydrogen peroxide (as an intermediate species) at −0.45 V vs Ag/AgCl and its chemical oxidation of the surface bound Tet@MWCNT to Tet-HQ@MWCNT is proposed as a plausible mechanism. Separate ring-disk screen-printed carbon electrode assembly, where MWCNT and a H2O2 detection catalyst (nano-MnO2) modified on the ring and disk respectively, coupled with flow injection analysis showed specific current signals for oxygen reduction reaction at −0.45 V vs Ag/AgCl on the disk and subsequent H2O2 oxidation on ring at 0.8 V vs Ag/AgCl. The surface confined redox system showed highly selective electrocatalytic reduction signal to hydrogen peroxide at ∼0.22 V vs Ag/AgCl without any interference from the ascorbic acid, uric acid, cysteine and nitrite
Jens Christoffers - One of the best experts on this subject based on the ideXlab platform.
-
Oxacycloalkenyliden‐Komplexe von Chrom, Molybdän und Wolfram: Synthese, Anellierung mit Alkinen und Diels‐Alder‐Reaktionen mit Dienen
Chemische Berichte, 1995Co-Authors: Jens Christoffers, Karl Heinz DötzAbstract:Reactions of Complex Ligands, LXI[1]. - Oxacycloalkenylidene Complexes of Chromium, Molybdenum, and Tungsten: Synthesis, Their Annulation with Alkynes and Diels-Alder Reaction with Dienes Lithiiated propargylic ether 1 reacts with M(CO)6 (M = Cr, Mo, W) to give the 2-oxacyclic carbene complexes 2–4 containing an α,β-double bond and a cyclic acetal structure which serves as a protected benzoyl group. Reaction of the chromium complex 2 with tolan leads to an acyl Hydroquinone Derivative 5. The tungsten complex 3 undergoes a [4 + 2] cycloaddition with cyclopentadiene to give two diastereomeric oxatricyclic carbene complexes 6 and 7 with an endo/exo selectivity of 3:1. The stereochemistry of the Diels-Alder reaction is controlled by the configuration of the acetal carbon center.
-
Novel synthesis of oxacycloalkenylidene complexes and their annulation to an acyl Hydroquinone Derivative
J. Chem. Soc. Chem. Commun., 1993Co-Authors: Jens Christoffers, Karl Heinz DötzAbstract:2-Oxacyclopentenylidene complexes of chromium and tungsten are formed in a one pot reaction from lithiated prop-2-ynylic ether and the metal carbonyl; the chromium complex undergoes annulation by tolan to give an acyl Hydroquinone skeleton.
