Aquation

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

Micellar effects on the kinetics of the aquation and the base hydrolysis of tris(1,10-phenanthroline)iron(II) and chloropentaamminecobalt(III) ions

Abstract: Les constantes de vitesse ne presentent pas de variations remarquables au-dessus de c.m.c. Pour Fe(phen) 3 2+ , au-dessous de c.m.c., les variations des constantes de vitesse sont liees a la formation d'agregats premicellaires. Effet de l'addition de NaCl

Redox-active cobalt complexes as promising antitumor agents

Abstract: Cobalt(iii) complexes with tetradentate aliphatic Schiff"s bases containing also compounds of the vitamin PP series or their analogs as axial ligands were synthesized as potential antitumor agents. The behavior of these redox-active complexes in chemical processes that presumably govern their biological action was studied. These processes include aquation and subsequent decomposition, electrode and homogeneous redox reactions, and catalytic activity in autooxidation of biosubstrates, especially at the stages of generation and consumption of reactive oxygen species (ROS). The antitumor action of these complexes in vivo was studied. Changes in the organisms of laboratory animals characteristic of processes involving ROS were followed at the cellular and molecular levels. The tumor-selective action of the complexes is due to specific features of microenvironment of tumor cells. Some of them exhibit a strong antimetastatic effect, which exceeds that for a number of drugs used in clinical practice. A complex with nicotinamide was recommended for preclinical studies. The scope of application of the redox-active transition metal complexes in oncology is discussed.

Mechanisms and Factors Controlling Photoisomerization Equilibria, Ligand Exchange, and Water Oxidation Catalysis Capabilities of Mononuclear Ruthen­ium(II) Complexes

Abstract: The photoisomerization equilibrium between distal- and proximal-[Ru(tpy)(pyqu)OH2]2+ [d- and p-RuH2O, tpy = 2,2′;6′,2″-terpyridine, pyqu = 2-(2′-pyridyl)quinoline] is characterized. The kinetic analysis of the pD-dependent photoisomerization reactions (monitored by 1H NMR) of d-RuH2O and p-RuH2O shows (1) that both hydroxo isomers, distal- and proximal-[Ru(tpy)(pyqu)OH]+, are inert to photoisomerization, and (2) that the back reaction (distal to proximal) is 3.0 times faster than the forward reaction (proximal to distal). Isolation of distal- and proximal-[Ru(tpy)(pyqu)Cl]+ (d- and p-RuCl) as well as d- and p-RuH2O isomers enabled comprehensive studies on geometric structures, ligand exchange and redox reactions, and water oxidation catalysis for these isomers. The observed aquation rate constant (9.2 × 10–2 s–1 at 40 μM) of p-RuCl to form p-RuH2O is 1700 times higher than that (5.4 × 10–5 s–1 at 63 μM) of d-RuCl at 298 K owing to the steric repulsion between a chloro ligand and the 8-proton of the quinoline moiety. The turnover frequency (TOF = 1.7 × 10–3 s–1) of p-RuH2O for catalytic water oxidation is 1.7 times greater than that (1.0 × 10–3 s–1) for d-RuH2O, in contrast to the [Ru(tpy)(pynp)OH2]2+ isomer system, in which the TOF of the distal isomer is higher than that of the proximal one by one order of magnitude. The mechanisms and factors controlling the photoisomerization equilibria and water oxidation catalysis of the d- and p-RuH2O isomers are discussed on the basis of experimental and theoretical investigations.