Aquation

About: Aquation is a research topic. Over the lifetime, 1443 publications have been published within this topic receiving 17507 citations.

Activation Volumes for a Series of Spontaneous, Acidand Base-Catalysed Aquation Reactions of Aniono trans- [Co(MeNH2)(NH3)4X]2,1+ Complexes (X=Cl-, Br-,ΝO3-,SO42-)

Abstract: Abstract The volumes of activation for the spontaneous, base-, and acid- catalysed path of the hydrolysis reaction of a series of trans-[Co(MeNH2)(NH3)4X](3-n)+ ions (X = Cl-, Br-, (ONO2)- (OSO3)2-) have been determined in order to establish analogies with the dissociative trends found in previous work with the spontaneous hydrolysis of neutral ligands from the same cores. While for the base catalysed path a significant decrease in the activation volume is found on going from the {Co(NH3)5} to the trans- {Co(MeNH2)(NH3)4} inert skeleton (i.e. 9.8, 12.5, 4.0 and 9.1 cm3 mol-1 for the chloro, bromo, nitrato and sulfato derivatives), no significant changes are observed for the same complexes in the spontaneous reaction. The trends are rationalized in terms of the important changes occurring in electrostriction factors for the DCB and Id intimate mechanisms operating and the important increase in the degree of dissociativeness due to the presence of a trans-methylamino ligand. For the acid catalysed path the differences are much more difficult to assess, specially taking into account the limited information available as well as the inherent errors involved in the rate constant determination.

Electrochemical Study of cis-Cyanoaquobis(ethylenediamine)chromium(III) Ion and Its Adducts with Hg(II) and Ag(I)

Abstract: Electrochemical properties of [Cr(CN 2 )(en) 2 ] + are described. Reactions of this complex with Hg(II) and Ag(I) were studied. Their stoichiometry (1 : 1) was determined using potentiometric and amperometric titration. Different pulse voltammetry (DPV) was applied to identify their products - dinuclear adducts. It was concluded on the bases of DPV experiments that linkage isomerization of bridding cyano ligand occurs in the process of adducts formation. The decomposition (aquation) of these adducts was followed and the influence of H + and Hg 2+ concentration on its rate was measured and discussed. The paper also deals with a spontaneous isomerization of unstable CN linkage isomers Cr(NC) 2 and Cr(CN)(CN) to the stable isomer Cr(NC) 2 .

Effect of solvent on the reactions of coordination complexes: Part 15: Base hydrolysis ofCis‐(Chloro)(benzimidazole)‐Bis‐(ethylenediamine)cobalt(III) ion in mixed solvent media

Abstract: The kinetics of base hydrolysis ofthecis-(chloro)-(benzimidazole)bis(ethylenediamine) cobalt(III) ion was investigated in Methanol-water and Ethyleneglycol-water media of varying compositions and at isodielectric conditions(D s □ 61 at 25°C) in isopropanol- and Acetonitrile-water media at 35°C in the pH range, 7.2–8.9. It is of interesttonote that the aquation rate constant of the conjugate base, cis-[Co(en) 2 (bzm)Cl] + (Bzm = N-H deprotonated benzimidazole, en = ethylenediamine) is virtually insensitive to the compositions of the mixed solvents studied, unlike the aquation rate constant of the conjugate acid form of the title complex. This is indicative of a true dissociative mode of activation (Dcb) of the conjugate base.