Deciphering the mechanism of O₂ reduction with electronically tunable non-heme iron enzyme model complexes

Abstract

A homologous series of electronically tuned ligands were prepared and some of their corresponding Fe complexes were prepared and a Hammett plot of the rates of O2 reduction allowed us to infer important details of the mechanism.

Regulating the Basicity of Metal–Oxido Complexes with a Single Hydrogen Bond and Its Effect on C–H Bond Cleavage

“…We have re-designed [H 3 buea] 3- into the new hybrid ligands [H 3 bpuea-R] 3- (R = OMe, H, F, Cl, CF 3 , 5F) in which one of the tripodal arms contains a pheny lurea unit (Figure 2). 34 Notice that two of the tripodal arms are the same in each ligand with urea groups that contain appended tert-butyl groups as in [H 3 buea] 3- . However, the third arm is modified to influence the remaining H-bond.…”

Unexpected Intramolecular Phosphite‐Mediated Amide Coupling To Yield 3,5‐Dioxo‐1‐Piperazines

“…To gain a deeper understanding of the structure of 1, a series of 2-dimensional bond correlation spectroscopic experi-Scheme 1. (a) Synthesis of tripodal carboxamides from 4-substituted anilines as reported previously, [9] and as described herein synthesis of 3,5-dioxo-1piperazine products (1-3) from 2,6-di-substituted anilines. py = pyridine.…”

“…Furthermore, it is known from previous synthetic efforts that 4-substituted and 3,5-di-substituted aniline derivatives are tolerated for the coupling reactions, yielding the desired tripodal carboxamide ligands in high yields and purity. [9,11] These observations suggest that the reaction outcome appears to be dictated by the presence of groups at the ortho-position of the aniline moiety, resulting in an intramolecular coupling reaction, generating a six-membered 3,5dioxo-1-piperazine unit. A review of the literature reveals ample synthetic strategies for forming 3,5-dioxo-1-piperazine rings.…”

“…[8] The synthesis of H 3 L R using para-substituted anilines is readily achieved using this method, generating the desired C 3v symmetric tripodal amide in a good yield and high purity (Scheme 1). [9] However, these ligand derivatives do not offer the steric bulk nor oxidative protection at the 2,6-positions of the aromatic ring.…”

Bioinspired nonheme iron complex that triggers mitochondrial apoptotic signalling pathway specifically for colorectal cancer cells

“…The Fe•••Fe distance (3.530(1) Å) and the Fe-O distance (1.7799(4) Å) were consistent with a μ-oxo bridged diiron complex (Table S2 †). [49][50][51][52][53] Reactivity of 1 towards Dioxygen and Hydrogen Peroxide.…”