Trapping of a phenoxyl radical at a non-haem high-spin iron(II) centre.

The activation of dioxygen at haem and non-haem metal centres, and subsequent functionalization of unactivated C‒H bonds, has been a focal point of much research. In iron-mediated oxidation reactions, O binding at an iron(II) centre is often accompanied by an oxidation of the iron centre. Here we demonstrate dioxygen activation by sodium tetraphenylborate and protons in the presence of an iron(II) complex to form a reactive radical species, whereby the iron oxidation state remains unaltered in the presence of a highly oxidizing phenoxyl radical and O.

A high-spin alkylperoxo-iron(iii) complex with -anionic ligands: implications for the superoxide reductase mechanism.

The NO macrocycle of the 12-TMCO ligand stabilizes a high spin ( = 5/2) [Fe(12-TMCO)(OOBu)Cl] (3-Cl) species in the reaction of [Fe(12-TMCO)(OTf)] (1-(OTf)) with -butylhydroperoxide (BuOOH) in the presence of tetraethylammonium chloride (NEtCl) in acetonitrile at -20 °C. In the absence of NEtCl the oxo-iron(iv) complex 2 [Fe(12-TMCO)(O)(CHCN)] is formed, which can be further converted to 3-Cl by adding NEtCl and BuOOH. The role of the -chloride ligand in the stabilization of the Fe-OOBu moiety can be extended to other anions including the thiolate ligand relevant to the enzyme superoxide reductase (SOR).

A New Thiolate-Bound Dimanganese Cluster as a Structural and Functional Model for Class Ib Ribonucleotide Reductases.

In class Ib ribonucleotide reductases (RNRs) a dimanganese(II) cluster activates superoxide (O ⋅ ) rather than dioxygen (O ), to access a high valent Mn -O -Mn species, responsible for the oxidation of tyrosine to tyrosyl radical. In a biomimetic approach, we report the synthesis of a thiolate-bound dimanganese complex [Mn (BPMT)(OAc) ](ClO) (BPMT=(2,6-bis{[bis(2-pyridylmethyl)amino]methyl}-4-methylthiophenolate) (1) and its reaction with O ⋅ to form a [(BPMT)MnO Mn] complex 2. Resonance Raman investigation revealed the presence of an O-O bond in 2, while EPR analysis displayed a 16-line S =1/2 signal at g=2 typically associated with a Mn Mn core, as detected in class Ib RNRs.

Evidence of Sulfur Non-Innocence in [Co (dithiacyclam)] -Mediated Catalytic Oxygen Reduction Reactions.

In many metalloenzymes, sulfur-containing ligands participate in catalytic processes, mainly via the involvement in electron transfer reactions. In a biomimetic approach, we now demonstrate the implication of S-ligation in cobalt mediated oxygen reduction reactions (ORR). A comparative study between the catalytic ORR capabilities of the four-nitrogen bound [Co(cyclam)] (1; cyclam=1,5,8,11-tetraaza-cyclotetradecane) and the S-containing analog [Co(S N -cyclam)] (2; S N -cyclam=1,8-dithia-5,11-diaza-cyclotetradecane) reveals improved catalytic performance once the chalcogen is introduced in the Co coordination sphere.

Temporal trends in treatment strategies and clinical outcomes among patients with advanced chronic kidney disease and ST-elevation myocardial infarctions: results from the Bremen STEMI registry.

Background: Although the detrimental effects of advanced chronic kidney disease (CKD) on prognosis in coronary artery disease is known, there are few data on the efficacy and safety of modern interventional therapies and medications in patients with advanced CKD, because this special patient cohort is often excluded or underrepresented in randomized trials.

Methods: In the present study all patients admitted with ST-elevation myocardial infarctions (STEMI) from the region of Bremen/Germany treated between 2006 and 2019 were analyzed. Advanced CKD was defined as glomerular filtration rate < 45 ml/min.