Aquation

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

Mechanism for formation and aquation of palladium(II) acetonitrile complexes in aqueous solution. Variable-temperature and variable-pressure study of stabilities and kinetics

Abstract: Mechanism for Formation and Aquation of Palladium(II) Acetonitrile Complexes in Aqueous Solution : Variable-Temperature and Variable-Pressure Study of Stabilities and Kinetics

The trans effect in cobalt(III) complexes. Kinetics and mechanism of substitution of cobalt(III) sulphito complexes

Abstract: Equilibrium constants K and rate constants kf have been measured, at 25°C and ionic strength of 1.0, for the substitution of the labile water molecule in trans-[aquabis(ethylenediamine)sulphito-cobalt(III)] ion by thiosulphate ion (K = 1.8×102 mol-1 1., kf = 1.27×103 mol-1 1. s-1), thiocyanate ion (2.5×103, 2.75×102), nitrite ion (1.0×103, 2.06×102), azide ion (2.9×102, 2.4×102) ferricyanide ion (-, 1.72×103), hydrogen azide (< 1.2,1.4×10), ammonia (3.0, 6.7) and imidazole (2.6×102, 5.2). The correlation of these rate constants with charge on the incoming ligand, as well as a decrease in the apparent second-order rate constants observed at high concentrations of the anionic ligands, requires a rapid outer-sphere pre-equilibrium step followed by a rate- determining dissociative interchange of the incoming ligand with the bound water molecule. The activation energy of the thiocyanate substitution was found to be 48 kJ mol-1. Aquation of cis- [azidobis(ethylenediamine)-sulphitocobalt(III)] ion, in the range of hydrogen ion concentration between 10-2 and 0.2 M, was found to give the trans-aquasulphito complex with a first-order rate constant consistent with the equation k = 4.9×10-4[H+]+1.0×10-5 s-1 at 25°C and ionic strength 1.0.

Inclusion compounds of cucurbit[n]urils with metal complexes

Abstract: A new class of supramolecular compounds—inclusion compounds of metal complexes encapsulated in organic macrocyclic cavitands cucurbit[n]urils (CB[n], C6n H6n N4n O2n , n = 7−10)—has been surveyed. A unique combination of a rather rigid hydrophobic intramolecular cavity and negatively charged portals favors the formation of stable host-guest compounds. Basic methods of synthesis of inclusion compounds of CB[n] with metal complexes have been reported, and the structures of the resulting products isolated as crystals and characterized by X-ray crystallography have been considered. The effect of encapsulation on the geometric and spectral characteristics of the complexes and their redox properties has been traced. It has been shown that encapsulation in CB[n] can lead to a change in the reactivity of the complexes in thermolysis and isomerization and aquation reactions. Encapsulation of biologically active metal complexes in CB[n] is a promising strategy for designing new-generation prolonged-action pharmaceuticals.