Kinetics and Mechanism of the Autocatalytic Oxidation of Bis(terpyridine)iron(II) by Peroxomonosulfate Ion (Oxone) in Acidic Medium

Chemistry towards Biology-Instruct: Snapshot

The knowledge of interactions between different molecules is undoubtedly the driving force of all contemporary biomedical and biological sciences. Chemical biology/biological chemistry has become an important multidisciplinary bridge connecting the perspectives of chemistry and biology to the study of small molecules/peptidomimetics and their interactions in biological systems. Advances in structural biology research, in particular linking atomic structure to molecular properties and cellular context, are essential for the sophisticated design of new medicines that exhibit a high degree of druggability and very importantly, druglikeness. The authors of this contribution are outstanding scientists in the field who provided a brief overview of their work, which is arranged from in silico investigation through the characterization of interactions of compounds with biomolecules to bioactive materials.

Efficient degradation of aqueous organic contaminants in manganese(II)/peroxymonosulfate system assisted by pyridine organic ligands

Although manganese(II) is known to have no role in peroxymonosulfate (PMS) activation, through a series of sulfamethoxazole (SMX) oxidation experiments, we found that the addition of pyridine organic ligands can improve the catalytic activity and accelerate SMX oxidation. For the organic ligands to be effective: the stability constant of the Mn(III) complex should be higher than that of the Mn(II) complex. A positive correlation was observed between the SMX oxidation rate and Mn(II) concentration, and the maximum PMS utilization efficiency was achieved. Many shreds of evidence verified that neither •SO₄^- nor •OH was associated with SMX oxidation. The enhanced effect of phenanthroline on the Mn(II)/PMS system was attributed to the highly oxidative intermediate manganese species (Mn(V)), originating from the two-electron transfer reaction of complexed Mn(III) and PMS. Notably, the main oxidizing species did not change (η-(PMSO₂) ∼ 100%) regardless of the initial PMSO concentration or pH value. Additionally, the analysis of SMX degradation products revealed that the oxygen transfer oxidation pathway was dominant in the Mn(II)/phenanthroline/PMS system, while the N radical coupling pathway also contributed significantly to SMX oxidation. This work offers new insights into the formation of high-valent manganese species and provides a potential strategy for applying low-concentration Mn(II) to wastewater treatment.

Terpyridines as promising antitumor agents: an overview of their discovery and development

INTRODUCTION

The fused aromatic system of terpyridines makes them good, innocent ligands for various metals. The resulting complexes have been extensively studied for both their biological activity and physico-chemical properties. However, although free ligands also have an interesting biological activity, their share in recent research is considerably limited.

AREAS COVERED

This review covers the literature on the anticancer activity of terpyridines with special attention being paid to their use as free ligands. Whenever possible, the mechanism of action has been discussed, thereby providing evidence of the substantial differences between sole ligands or less stable complexes and those that have heavier elements.

EXPERT OPINION

The existing literature indicates that there is a specific attitude for investigating terpyridines and their transition metal complexes. While the latter have been well explored and recognized in the scientific community, the free terpyridines are considered to be useful solely due to their complexing ability. At the same time, terpyridines could have similar or even higher anticancer potency than their complexes. Moreover, a mechanistic analysis of the stability and intracellular activity would provide information that would be useful for designing new drugs.

Supramolecular linear coordination polymers of human serum albumin and haemoglobin

We describe the synthesis, structure, and functionalities of water-soluble linear coordination polymers of human serum albumin and haemoglobin, which are connected via a bis(terpyridyl)-Fe²⁺ complex. These protein fibres were self-assembled by lyophilisation and were transformed into single-wall nanotubes. The biological activities of the protein units were perfectly preserved in the long fibres.

Oxidation-Responsive Emulsions Stabilized by Cleavable Metallo-Supramolecular Cross-Linked Microgels

An original route to develop an advanced class of microgel emulsifiers containing stimulable metallo-supramolecular instead of frozen covalent cross-links is reported. The poly(N-isopropylmethacrylamide) (PNiPMAM) chains of the microgel are connected by iron(II)-bis(terpyridine) coordination supramolecular complexes that can be cleaved on demand, leading to unique properties both at interfaces and in volume. The microgel synthesis is not demanding, and the characterization of its supramolecular structure can be precisely achieved by standard methods. Singularly, interfaces of an oil-in-water emulsion stabilized by the supramolecular particles can be triggered at the molecular scale by oxidation of Fe(II) to Fe(III), leading to emulsion breaking. In bulk, we show that a microgel dispersion can indeed be transformed into a polymer solution upon oxidation. Our study paves the way to the discovery of unusual microgel properties as our proof-of-concept can be extended to different supramolecular chemistry and architecture.

Sub-phthalocyanine-incorporated Fe(ii) metallo-supramolecular polymer exhibiting blue-to-transmissive electrochromic transition with high transmittance and coloration efficiency

The preparation of a new Fe(ii) metallo-supramolecular polymer (poly-subPc-Fe) constructed from a terpyridine-functionalized sub-phthalocyanine with axially substituted polyisobutylene is presented.