Nickel and copper complexes based on tridentate nitrogen donor ligand 2,6-bis-(1-phenyliminoethyl) pyridine: Synthesis, spectral and structural characterization

Pincer Ligands as Multifunctional Agents for Alzheimer's Copper Dysregulation and Oxidative Stress: A Computational Evaluation

Alzheimer's disease (AD) is the most common form of dementia worldwide, affecting millions of people around the globe. AD is characterized by different pathologies being beta-amyloid (Aβ) plaque formation, metal ion dysregulation, and oxidative stress (OS) central topics under investigation. Copper-Aβ complexes have been shown to induce catalytic hydrogen peroxide formation and increase OS in the brain leading to neuronal death. Pincer-type compounds are tridentate ligands that coordinate metals in a planar fashion whose properties can be tuned via group substitutions, giving rise to many possibilities in catalysis and drug discovery. In this work we evaluated the potential pharmaceutical activity of 26 pincer compounds in AD's copper ion-related oxidative stress framework. In this sense, four key aspects were considered: 1) Lipinski's rule of five, 2) blood-brain barrier permeation, 3) standard reduction potential (SRP) of the formed copper complexes, and 4) the ligand's affinity towards copper cations. The evaluation of these criteria was performed by means of bioinformatic tools and electronic structure calculations at the DFT level of theory. Our results suggest that two compounds from this set are potential antioxidant agents, whereas five of them are promissory distributor-like compounds in the context of AD.

Structures, properties and applications of Cu(II) complexes with tridentate donor ligands

Tridentate ligands offer theree donor atoms to coordinate to metal ions. The remaining vacant coordination sites on the metal ions provided opportunities to implement additional co-ligands to generate complexes with desired properties. Herein we discuss selected examples of Cu(ii) complexes with tridentate ligands utilizing combinations of N, O, S, and Se donors, focusing on effects of ligand flexibility/rigidity on their coordination modes, properties and applications.

{2,6-Bis[1-(phenyl-imino)eth-yl]pyridine-κN,N',N''}dichloridocobalt(II)

In the title complex, [CoCl₂(C₂₁H₁₉N₃)], the Co^II atom is coordinated by one pyridine and two imine N atoms and by two chloride anions in a distorted trigonal bipyramidal geometry. The structure exhibits a pseudo-mirror plane through the metal atom, two chloride anions and the pyridine ring. In the crystal structure, the complexes are connected via inter­molecular C—H⋯Cl hydrogen bonding.