Kinetic study of ferrous nitrosyl complexes

Kinetic, mechanistic, and DFT study of the electrophilic reactions of nitrosyl complexes with hydroxide.

We present a kinetic study of OH(-) additions to several nitrosyl complexes containing mainly ruthenium and different coligands (polypyridines, amines, pyridines, cyanides). According to a first-order rate law in each reactant, we propose a fast ion pair formation equilibrium, followed by addition of OH(-) to the [MX(5)NO](n) moieties, with formation of the [MX(5)NO(2)H](n(-1)) intermediates. A...

Electron paramagnetic resonance studies of nitrosyl ferrous heme complexes. Determination of an equilibrium between two conformations.

Ferrous hemeproteins and inorganic heme complexes react with nitric oxide to form six-coordinate paramagnetic complexes. These complexes exhibit strong EPR signals centered near g = 2.0 which are easily observed in frozen solution. We have obtained EPR spectra of the nitrosyl adducts of Fe(II) protoporphyrin IX-imidazole in dimethylsulfoxide and in dimethylformamide, and of myoglobin, cytochrom...

Characterization of two different five-coordinate soluble guanylate cyclase ferrous-nitrosyl complexes.

Soluble guanylate cyclase (sGC), a hemoprotein, is the primary nitric oxide (NO) receptor in higher eukaryotes. The binding of NO to sGC leads to the formation of a five-coordinate ferrous-nitrosyl complex and a several hundred-fold increase in cGMP synthesis. NO activation of sGC is influenced by GTP and the allosteric activators YC-1 and BAY 41-2272. Electron paramagnetic resonance (EPR) spec...

The Electron Transfer Chemistry of Nitrosyl Complexes

The reactions of nitrosyl complexes with cysteine.

The reaction kinetics of a set of ruthenium nitrosyl complexes, {(X)5MNO}n, containing different coligands X (polypyridines, NH3, EDTA, pz, and py) with cysteine (excess conditions), were studied by UV-vis spectrophotometry, using stopped-flow techniques, at an appropriate pH, in the range 3-10, and T = 25 degrees C. The selection of coligands afforded a redox-potential range from -0.3 to +0.5 ...