Ligand Effects on the Kinetics of the Reversible Binding of NO to Selected Aminocarboxylato Complexes of Iron(II) in Aqueous Solution

Abstract

Rate constants for the formation and dissociation of FeII(L)NO (L = aminocarboxylato) have been determined using stopped‐flow, temperature jump, flash photolysis, and pulse radiolysis techniques. For a series of ligands the formation rate constants vary between 1.6 × 106 and 2.4 × 108 M−1 s−1, whereas the dissociation rate constants vary between 0.11 and 3.2 × 103 s−1 at 25 °C. These rate constants result in stability constants (KNO = kf/kd) ranging from 5.0 × 102 to 1.1 × 107 M−1, which are in good agreement with values of KNO determined by a combined spectrophotometric and potentiometric technique. The results are discussed with reference to available literature data, and interpreted in terms of a generalized reaction mechanism.

Mechanistic information on the nitrite-controlled reduction of aquacob(III)alamin by ascorbate at physiological pH

“…9, reacts very rapidly with NO to form the green-brown Fe II (edta)NO complex, red line in 9. The reaction of CblNO 2 with Asc was carried out in the presence of an excess nitrite (6 mM) and 1 mM Fe(edta) [19]. The lack of spectral changes similar to those shown in Fig.…”

The role of positively charged meso-substituents on the kinetics of the reductive nitrosylation of iron(III)-porphyrins

“…It is also known that Fe(III)-porphyrins react several orders of magnitude faster with NO than other Fe(III) complexes in acidic media [6]. In fact, Fe III (edta)H 2 O does not react with NO at all, whereas the corresponding Fe II (edta)H 2 O complex is an excellent NO scavenger [7]. The characteristic reactivity of Fe(III)-porphyrins has led to an increasing interest in this chemistry over the past years.…”

Mass Transfer in Reactive Bubbly Flows – A Single‐Bubble Study

“…Comparing the stability constant of [Fe(EDTA)(NO)] ) [22,23], the stability effect of the chelate ligand is obvious. However, the stability of the Fe II (Ligand)-NO system is not fully understood since the exact mechanism of the product formation and the rules of the relationship of structure and feature are, to our knowledge, still unknown.…”