Iron(II)-Catalyzed Hydrogenation of Acetophenone with a Chiral, Pyridine-Based PNP Pincer Ligand: Support for an Outer-Sphere Mechanism

2018 ◽  
Vol 37 (3) ◽  
pp. 396-405 ◽  
Author(s):  
Raffael Huber ◽  
Alessandro Passera ◽  
Antonio Mezzetti
Keyword(s):  
Outer Sphere ◽  
Pincer Ligand ◽  
Sphere Mechanism

Kinetics and mechanism of redox reactions of U(III) ions with monochloroacetic and dichloroacetic acids

1979 ◽  
Vol 44 (2) ◽  
pp. 401-405 ◽  
Author(s):  
Ľubica Adamčíková ◽  
Ľudovít Treindl
Keyword(s):  
Redox Reactions ◽  
Reaction Rate ◽  
Activation Parameters ◽  
Outer Sphere ◽  
Alcohol Concentration ◽  
Kinetics And Mechanism ◽  
Solvent Structure ◽  
Influence Of Ph ◽  
Sphere Mechanism

The kinetics and mechanism of the redox reactions of U3+ ions with mono- and dichloroacetic acids were studied. The influence of pH was observed mainly in the second case and led to the determination of the rate constants and activation parameters corresponding to two parallel steps, namely oxidation of U3+ with CHCl2COO- ions and oxidation of U3+ with CHCl2.COOH molecules. The influence of binary mixtures of water with methanol, ethanol, isopropanol, or tert-butenol on the reaction rate was followed. Increasing alcohol concentration influences the rate constant not only through changing dielectric constant and solvation of the reactants but also through a change of the solvent structure which plays a role in reactions with an outer sphere mechanism of the electron transfer.

scholarly journals RuIII(edta) complexes as molecular redox catalysts in chemical and electrochemical reduction of dioxygen and hydrogen peroxide: inner-sphere versus outer-sphere mechanism

RSC Advances ◽  
2021 ◽  
Vol 11 (35) ◽  
pp. 21359-21366
Author(s):  
Debabrata Chatterjee ◽  
Marta Chrzanowska ◽  
Anna Katafias ◽  
Maria Oszajca ◽  
Rudi van Eldik
Keyword(s):  
Hydrogen Peroxide ◽  
Electron Transfer ◽  
Electrochemical Reduction ◽  
Molecular Oxygen ◽  
Outer Sphere ◽  
Transfer Processes ◽  
Edta Complexes ◽  
Inner Sphere ◽  
Electron Transfer Processes ◽  
Sphere Mechanism

[RuII(edta)(L)]2–, where edta4– =ethylenediaminetetraacetate; L = pyrazine (pz) and H2O, can reduce molecular oxygen sequentially to hydrogen peroxide and further to water by involving both outer-sphere and inner-sphere electron transfer processes.

scholarly journals Dy-DOTA integrated mesoporous silica nanoparticles as promising ultrahigh field magnetic resonance imaging contrast agents

Nanoscale ◽  
2018 ◽  
Vol 10 (45) ◽  
pp. 21041-21045 ◽  
Author(s):  
Xiao-Yu Zheng ◽  
Juan Pellico ◽  
Alexandr A. Khrapitchev ◽  
Nicola R. Sibson ◽  
Jason J. Davis
Keyword(s):  
Magnetic Resonance Imaging ◽  
Mesoporous Silica ◽  
Mesoporous Silica Nanoparticles ◽  
Silica Nanoparticle ◽  
Outer Sphere ◽  
Resonance Imaging ◽  
Mesoporous Silica Nanoparticle ◽  
Ultrahigh Field ◽  
Magnetic Resonance Imaging Contrast ◽  
Sphere Mechanism

Integrating Dy-DOTA motifs into mesoporous silica nanoparticle scaffolds significantly amplifies the ultrahigh field T2 relaxivity via a Curie outer-sphere mechanism.

Mechanism of Zn(OTf)2catalyzed hydroamination–hydrogenation of alkynes with amines: insight from theory

2017 ◽  
Vol 41 (12) ◽  
pp. 5082-5090 ◽  
Author(s):  
Riffat Un Nisa ◽  
Khurshid Ayub
Keyword(s):  
Transition Metals ◽  
Outer Sphere ◽  
Late Transition Metals ◽  
Late Transition ◽  
Sphere Mechanism

Zn(OTf)2catalyzed hydroamination of alkynes with amines proceeds through an outer sphere mechanism which is contrary to other late transition metals.

scholarly journals Synthesis and Oxidation ofCobalt(II) Pheophytin-α Complex

2011 ◽  
Vol 8 (s1) ◽  
pp. S297-S303 ◽  
Author(s):  
Ezekiel D. Dikio ◽  
David A. Isabirye
Keyword(s):  
Metal Ion ◽  
Oxidation Reaction ◽  
Dilute Hydrochloric Acid ◽  
Outer Sphere ◽  
Central Metal ◽  
First Order ◽  
First Order Kinetics ◽  
Mechanism Of Oxidation ◽  
Absorption Transitions ◽  
Sphere Mechanism

The mechanism of oxidation of natural pheophytin-aincorporated with cobalt as the central metal ion has been investigated. Natural pheophytin-aextracted from spinach was metallated with cobalt(II) to form the complex, cobalt(II) pheophytin-α[Cophe]. The complex was characterized by Ultraviolet and Visible, Fourier Transform Infrared and Electrospray ion Mass Spectroscopy. The synthesis of cobalt(II) pheophytin-awas carried out and the effect of the substitution on the chlorophyll macrocycle was studied by the reaction of hexaaquachromium(III) cation. The presence of cobalt as the central metal ion increases the energies of the chlorophyll main absorption transitions. The oxidation of the cobalt(II) pheophytin-α, [Cophe] by hexaaquachromium(III) cation in dilute hydrochloric acid has been studied and found to follow first-order kinetics. Rate constants for the oxidation reaction at 313, 322.8 and 332.9 K were found to be 5.4×10-5, 1.8×10-4and 5.9×10-4/s respectively. An outer-sphere mechanism has been proposed for the oxidation of cobalt(II) pheophytin-α.

Oxidation of low-spin iron(II) porphyrins by molecular oxygen. An outer sphere mechanism

Biochemistry ◽  
1978 ◽  
Vol 17 (3) ◽  
pp. 481-486 ◽  
Author(s):  
Margaret M. L. Chu ◽  
C. E. Castro ◽  
G. M. Hathaway
Keyword(s):  
Molecular Oxygen ◽  
Outer Sphere ◽  
Sphere Mechanism

Outer-sphere electron transfer reactions of aqua(5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-1-acetato) nickel(II) and (III).

2003 ◽  
Vol 81 (2) ◽  
pp. 186-192 ◽  
Author(s):  
Robert I Haines ◽  
Dean R Hutchings
Keyword(s):  
Electron Transfer ◽  
Exchange Rate ◽  
Outer Sphere ◽  
Second Order ◽  
Marcus Theory ◽  
Pendant Arm ◽  
Key Words Nickel ◽  
Kinetics Of ◽  
Kinetics Of Reduction ◽  
Sphere Mechanism

The outer-sphere oxidation of the nickel(II) complex of the deprotonated pendant-arm macrocycle, 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-1-acetate, [NiL1(OH2)]+ by bis-(1,4,7-triazacyclononane)nickel(III), [Ni(tacn)2]3+ has been studied in aqueous perchlorate media. The reaction displays reversible second-order behaviour and the kinetic study reveals the forward and reverse rate constants for the reaction: [Formula: see text] The kinetics show the forward reaction to be acid dependent, a feature that is attributed to protonation of the acetato group of the nickel(II) complex. Using Marcus theory, the self-exchange rate for the [NiL1(OH2)]+/2+ couple has been calculated. The nickel(II/III) electron transfer is a reversible one electron process with E° = 1.04 V (vs. S.H.E.). The formation of the authentic nickel(III) product has been confirmed by esr spectroscopy. The kinetics of reduction of the [NiL1(OH2)]2+ species by Fe2+(aq) exhibits a second-order rate law, the reaction being independent of acid. Using the calculated self-exchange rate for the nickel complex, its reaction with Fe2+(aq) has been examined in terms of an inner- versus outer-sphere mechanism. Key words: nickel(III), pendant-arm macrocycles, hexaaquairon(II), outer sphere, kinetics, Marcus theory.

A Non-Outer Sphere Mechanism for the Ionization of Aryl Vinyl Sulfides by Triarylaminium Salts

1997 ◽  
Vol 119 (47) ◽  
pp. 11381-11389 ◽  
Author(s):  
Nathan L. Bauld ◽  
J. Todd Aplin ◽  
Wang Yueh ◽  
Ainhoa Loinaz
Keyword(s):  
Outer Sphere ◽  
Vinyl Sulfides ◽  
Sphere Mechanism

scholarly journals Kinetics and Mechanism of Redox Reaction of Neutral Red with Nitrite Ion in Aqueous Acidic Medium

2016 ◽  
Vol 67 ◽  
pp. 50-57
Author(s):  
Ismaila Ibrahim ◽  
Sulaiman Ola Idris ◽  
Ameh David Onu
Keyword(s):  
Redox Reaction ◽  
Outer Sphere ◽  
Neutral Red ◽  
Nitrite Ion ◽  
First Order ◽  
Hydrochloric Acid Medium ◽  
Plausible Mechanism ◽  
Kinetics Of ◽  
Sphere Mechanism ◽  
Aqueous Acidic Medium

The kinetics of redox reaction of neutral red, NR+, with nitrite ion, NO2-, was studied in aqueous hydrochloric acid medium under pseudo-first order conditions at 25 ± 1°C, [H+] = 2.0 × 10-3mol dm-3, I = 0.1 mol dm-3(NaCl) and λmax= 525 nm. The reaction was first order with respect to [NR+], [NO2-] and [H+]. The reaction displayed a negative Bronsted-Debye salt effect. There was no evidence of the formation of an intermediate complex of significant stability and free radicals are probably not present in the reaction. The observations above, coupled with the result of Michaelis-Menten plot suggests an outer sphere mechanism for the reaction. The reaction obeys the rate law: -d [NR+]/dt = (a + b [H+])[NR+][NO2-]. A plausible mechanism has been proposed for the reaction.

Sign in / Sign up

Export Citation Format

Share Document