Thermodynamic and kinetic studies on the interaction of RuIII(edta) with NO in an ionic liquid

Abstract

The aim of this study was to determine rate constants for the release of NO from an iron(II) nitrosyl complex dissolved in a typical imidazolium-based ionic liquid, [emim][dca], using an NO trapping technique combined with stopped-flow measurements. The anionic component of the selected ionic liquid, viz. [dca] (dicyanamide), was found to coordinate to the Ru(III)(edta) complex used as trapping agent, and hindered its successful application. Further investigations in aqueous solution revealed thermodynamic and kinetic data for the formation of the [Ru(III)(edta)(dca)](2-) complex and its reaction with NO to form the corresponding nitrosyl complex. The results obtained under conditions similar to those in the ionic liquid indicated a much slower formation of the nitrosyl complex in [emim][dca] compared to that reported for the formation of this complex in aqueous medium.

Factors That Determine the Mechanism of NO Activation by Metal Complexes of Biological and Environmental Relevance

“…When the same starting Ru III complex is dissolved in [emim][dca], the formation of [Ru(edta)dca] 2– is expected because of a pronounced coordination ability of the [dca] anion, which can easily substitute the chloride ligand. Thermodynamic and kinetic investigations on the formation of [Ru(edta)dca] 2– from [Ru(edta)H 2 O] – and sodium dicyanide, Na(dca), in an aqueous solution at pH = 6 confirm this observation 26. In order to compare the NO scavenging properties of [Ru(edta)dca] 2– with that of [Ru(edta)H 2 O] – , detailed kinetic studies on the nitrosylation reaction of the former complex in an aqueous solution were performed 26.…”

“…Thermodynamic and kinetic investigations on the formation of [Ru(edta)dca] 2– from [Ru(edta)H 2 O] – and sodium dicyanide, Na(dca), in an aqueous solution at pH = 6 confirm this observation 26. In order to compare the NO scavenging properties of [Ru(edta)dca] 2– with that of [Ru(edta)H 2 O] – , detailed kinetic studies on the nitrosylation reaction of the former complex in an aqueous solution were performed 26. For the kinetic investigations, [Ru(edta)dca] 2– was prepared in situ by mixing the [Ru(edta)H 2 O] – complex with an excess of Na(dca) in aqueous solution at pH = 9, to simulate the conditions in the ionic liquid, which is expected to be basic.…”

“…Furthermore, [Ru III (edta)H 2 O] – , because of its high affinity for NO and oxygen insensitivity, was found to satisfy most of the requirements for an effective scavenger of nitric oxide in biological systems 25. In this context, our goal was to examine the applicability of the Ru III (edta) complex as a NO‐trapping agent in a selected ionic liquid such as [emim][dca] 26…”

Applied Kinetics Aspects of Ferric EDTA Complex Reduction with Metal Powder

“…The reagents of EDTA and NH 4 Fe(SO 4 ) 2 were supplied by POCH Co. (Poland). Aluminum and tin powders were provided by Riedel-deHean, and zinc powder was supplied by Fluka.…”

Reply to the Comment on the Article “Gutmann Donor and Acceptor Numbers for Ionic Liquids” (Chem. Eur. J. 2012, 18, 10969–10982) by J.‐F. Gal and C. Laurence

“…[1] Today between 300 and 400 ILs are commercially available. [2] In our own work we focused on the study of inorganic/bioinorganic reaction mechanisms in ionic liquids [3][4][5][6] especially in terms of the role of the anionic component of the IL that can be a potential nucleophile and act as a coordinating ligand for transitionmetal complexes. Indeed, even the rather simple ligand substitution process on square-planar complexes showed a characteristic dependence on the nature of the anionic component of the IL in terms of its nucleophilicity/basicity.…”