Catalytic Activation of Molecular Hydrogen by Ruthenium Chloride Complexes in N,N-Dimethylacetamide Solution

1974 ◽  
Vol 52 (2) ◽  
pp. 348-357 ◽  
Author(s):  
Benjamin C. Hui ◽  
Brian R. James
Keyword(s):  
Aqueous System ◽  
Water Production ◽  
Chloride Complexes ◽  
Catalytic Activation ◽  
Aqueous Acid ◽  
System A ◽  
Aqueous Solvent ◽  
Lower Activation ◽  
Amide Solvent ◽  
Detailed Interpretation

N, N-Dimethylacetamide solutions of "RuCl3•3H2O", which is a mixture of Ru (IV) and Ru(III), react with hydrogen under mild conditions in stepwise stoichiometric processes to give finally univalent species [Formula: see text]. Reactions 1 and 2 involve heterolytic activation of H2 by a Ru III catalyst and likely proceed via a RuIIIH intermediate; the same catalyst catalyzes the hydrogenolysis of oxygen to water. Reaction 3 involves a RuIIH intermediate. Kinetic parameters are presented for processes 1–3 and the catalytic water production, and are compared with data for some systems that have been studied previously in aqueous acid chloride solutions. Reactions 1 and 2 occur much more readily in the non-aqueous solvent due to a lower activation energy, while reaction 3 occurs only in the non-aqueous system. A detailed interpretation of the data is limited by the uncertain nature of species present in the amide solvent.

Methanolysis of the Intervertebral Disc

1967 ◽  
Vol 13 (6) ◽  
pp. 506-514 ◽  
Author(s):  
David Chan ◽  
E Wayne Hull ◽  
Marvin Fields ◽  
Earl McNall
Keyword(s):  
Intervertebral Disc ◽  
Acid Hydrolysis ◽  
Nucleus Pulposus ◽  
Hyaline Cartilage ◽  
Aqueous System ◽  
Acid Strength ◽  
Direct Relation ◽  
Reaction Products ◽  
Aqueous Acid ◽  
System A

Abstract Methanolysis of intervertebral disc samples at 60° was largely hydrolysis as shown by the absence of methylated derivatives on chromatograms of the reaction products. Extent of the reaction increased with acid strength; the products were the same. Maximum solubilization was about 80% and 50% for hyaline cartilage plate and nucleus pulposus samples, respectively. The results of aqueous acid (hydrolysis) for hyaline cartilage plate paralleled the methanolysis reaction. Nucleus pulposus samples did not show, in the aqueous system, a direct relation between acid strength and extent of reaction: 0.1 N acid solubilized more material than 1.0 N acid. Therefore, methanolysis and hydrolysis reactions may be used for differentiating tissue even though the basis of the "methylation blockade" of certain staining reactions is lost when performed at 60°.

scholarly journals High-efficiency photocatalytic CO2 reduction in organic–aqueous system: a new insight into the role of water

RSC Advances ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 3798-3802 ◽  
Author(s):  
Jinliang Lin ◽  
Rongying Liao ◽  
Junli Xu
Keyword(s):  
High Efficiency ◽  
Co2 Reduction ◽  
Liquid System ◽  
Aqueous System ◽  
Binary Liquid System ◽  
Binary Liquid ◽  
System A ◽  
System P ◽  
Insight Into

A high efficiency photocatalytic conversion of CO2 into CO has been achieved by construction of a binary liquid system.

Reactions of Ethylene with Rhodium (III) Chloride. Part IV. Relative Activity of Tetra-, Penta-, and Hexa-chlororhodate(III) Complexes for the Oxidation of Ethylene to Acetaldehyde in Aqueous Acid Solutions

1972 ◽  
Vol 50 (11) ◽  
pp. 1708-1712 ◽  
Author(s):  
B. R. James ◽  
M. Kastner
Keyword(s):  
Catalytic Oxidation ◽  
Relative Activity ◽  
Acid Solutions ◽  
Chloride Complexes ◽  
Chloro Complexes ◽  
Mild Conditions ◽  
Aqueous Acid ◽  
Coordinated Water

The catalytic oxidation of ethylene to acetaldehyde using the rhodium(III) chloride complexes, [Formula: see text] in the presence of iron(III) has been studied kinetically in aqueous acid solutions under mild conditions.[Formula: see text] is inactive due to the absence of a coordinated water (hydroxide) ligand. Solutions containing tetrachloro species are generally more reactive than those containing pentachloro species because of the presence of a greater concentration of highly reactive hydroxy species. The neutral and cationic chloro-complexes are inactive due to their substitution inertness.

scholarly journals Resolving the Ultrafast Dynamics of the Anionic Green Fluorescent Protein Chromophore in Water

2021 ◽  
Author(s):  
Chey Jones ◽  
Nanna Holmgaard List ◽  
Todd J. Martínez
Keyword(s):  
Excited State ◽  
Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Fluorescence Decay ◽  
Aqueous System ◽  
Vacuum System ◽  
Electronic Effects ◽  
Selective Stabilization ◽  
Aqueous Solvent ◽  
Green Fluorescent

The chromophore of the green fluorescent protein (GFP) is critical for probing environmental influences on fluorescent protein behavior. Using the aqueous system as a bridge between the unconfined vacuum system and a constricting protein scaffold, we investigate the steric and electronic effects of the environment on the photodynamical behavior of the chromophore. Specifically, we perform <i>ab initio </i>multiple spawning to simulate five picoseconds of nonadiabatic dynamics after photoexcitation, resolving the excited-state pathways responsible for internal conversion in the aqueous chromophore. We identify an ultrafast pathway that proceeds through a short-lived (sub-picosecond) imidazolinone-twisted (I-twisted) species and a slower (several picoseconds) channel that proceeds through a long-lived phenolate-twisted (P-twisted) intermediate. The molecule navigates the non-equilibrium energy landscape via an aborted hula-twist-like motion towards the one-bond-flip dominated conical intersection seams, as opposed to following the pure one-bond-flip paths proposed by the excited-state equilibrium picture. We interpret our simulations in the context of time-resolved fluorescence experiments, which use short and long time components to describe the fluorescence decay of the aqueous GFP chromophore. Our results suggest that the longer time component is caused by an energetically uphill approach to the P-twisted intersection seam rather than an excited-state barrier to reach the twisted intramolecular charge transfer species. Irrespective of the location of the non-adiabatic population events, the twisted intersection seams are inefficient at facilitating isomerization in aqueous solution. The disordered and homogeneous nature of the aqueous solvent environment facilitates non-selective stabilization with respect to I- and P-twisted species, offering an important foundation for understanding the consequences of selective stabilization in heterogeneous and rigid protein environments.

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