Exploring ligand non-innocence of coordinatively-versatile diamidodipyrrinato cobalt complexes

Maji

et al. 2021

Applied Organom Chemis

Bis(imino)pyridine (NNN)‐type ligand [(PyPhime‐Cina) = 2,6‐bis((E)‐1‐phenyl‐2‐((E)‐3‐phenylallylidene)hydrazinyl)pyridine] was synthesized, and a new family of metal complexes [Mn(PyPhime‐Cina)Cl2] (1), [Fe(PyPhime‐Cina)Cl2] (2), [Co(PyPhime‐Cina)Cl2] (3), [Ni(PyPhime‐Cina)Cl2] (4), and [Cu(PyPhime‐Cina)Cl2] (5), derived from the ligand, have been synthesized and characterized. Molecular structures of the ligand and complexes 1‐5 were determined using X‐ray crystallography. Electronic properties and frontier molecular orbitals of the complexes were investigated by DFT and TD‐DFT calculations. DNA interaction studies were evaluated by UV‐visible absorption, fluorescence and circular dichroism spectral studies which indicated noncovalent binding of complexes with CT‐DNA. Hirshfeld surface analysis of all the complexes was studied to know the weak interaction present in the molecules.

Section: Introductionmentioning

confidence: 99%

A new family of complexes derived from bis(imino)pyridine‐type ligands: Crystal structures and bio‐molecular interaction studies

Maji

et al. 2021

Applied Organom Chemis

“…This study presents the formation of easy-to-synthesize and bench-stable uranyl complexes of a diamidodipyrrin ligand and an evaluation of their reduction properties. A similar ligand has previously been exploited in the formation of boron and transition-metal complexes, such as nickel, copper, and cobalt, although these studies mainly focused on the rich coordination chemistry of these ligands. − We rationalized that the use of these ligands would deliver a uranyl complex that would potentially be resistant toward oxidation reactions and hydrolysis, while maintaining its redox properties.…”

Section: Introductionmentioning

confidence: 99%

Exploring the Redox Properties of Bench-Stable Uranyl(VI) Diamido–Dipyrrin Complexes

et al. 2022

The uranyl complexes UO 2 (OAc)( L ) and UO 2 Cl( L ) of the redox-active, acyclic diamido–dipyrrin anion L – are reported and their redox properties explored. Because of the inert nature of the complexes toward hydrolysis and oxidation, synthesis of both the ligands and complexes was conducted under ambient conditions. Voltammetric, electron paramagnetic resonance spectroscopy, and density functional theory studies show that one-electron chemical reduction by the reagent CoCp 2 leads to the formation of a dipyrrin radical for both complexes [Cp 2 Co][UO 2 (OAc)( L • )] and [Cp 2 Co][UO 2 Cl( L • )].

Enhanced Hydrogen Evolution in Neutral Water Catalyzed by a Cobalt Complex with a Softer Polypyridyl Ligand

et al. 2020

To explore the structure–function relationships of cobalt complexes in the catalytic hydrogen evolution reaction (HER), we studied the substitution of a tertiary amine with a softer pyridine group and the inclusion of a conjugated bpy unit in a Co complex with a new pentadentate ligand, 6‐[6‐(1,1‐di‐pyridin‐2‐yl‐ethyl)‐pyridin‐2‐ylmethyl]‐[2,2′]bipyridinyl (Py3Me‐Bpy). These modifications resulted in significantly improved stability and activity in both electro‐ and photocatalytic HER in neutral water. [Co(Py3Me‐Bpy)(OH2)](PF6)2 catalyzes the electrolytic HER at −1.3 V (vs. SHE) for 20 hours with a turnover number (TON) of 266 300, and photolytic HER for two days with a TON of 15 000 in pH 7 aqueous solutions. The softer ligand scaffold possibly provides increased stability towards the intermediate CoI species. DFT calculations demonstrate that HER occurs through a general electron transfer/proton transfer/electron transfer/proton transfer pathway, with H2 released from the protonation of CoII−H species.