An o-Phenylene Bridged Noninnocent Bis-Azopyridyl Ligand and Its Copper Complexes: Synthesis, Characterization of Electron Transfer Events, and Use of the Cu Complexes for Oxidation of Alcohols

Inorganic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: April 14, 2025

In this report, an o-phenylene-bridged tetradented redox-noninnocent bis-azopyridyl ligand [L] and its copper complexes [1] [2] were synthesized characterized. The electron transfer events of [L], as well [2], characterized by single-crystal X-ray structure determination, various spectroscopic studies, DFT calculations. While [[L]Cu(II)Cl2] has unreduced [[L]•-Cu(I)Cl] contains a one-electron-reduced [L]•- , which is antiferromagnetically coupled with the unpaired spin on Cu(II). Reduction one generated complex [2]•-, remained in electronically bistable situation form valence tautomers: [2A]•-, [[L]•-Cu(I)Cl]•- [2B]•-, [[L]2-Cu(II)Cl]•-. Further one-electron reduction [2]•- mixture Cu complexes: [2A]-, [[L]2-Cu(I)]- [2B]-, [[L]3•-Cu(II)]-. Complexes examined for catalytic oxidation alcohols. was more efficient than [1]. protocol highly versatile both primary secondary aromatic aliphatic Mechanistic investigations showed that [[L]•-Cu(I)OCH2Ph]•- (A) active catalyst, subsequently, through ligand-based redox events, acted catalyst over course reaction.

Language: Английский

Aerial Oxidation of Alcohols by an Amide and Imidazole Functionalized Bioinspired Cu‐Complex and Its Switching with N‐Oxides

ChemistrySelect, Journal Year: 2025, Volume and Issue: 10(18)

Published: May 1, 2025

Abstract In this work, employing an imidazole and amide functionalized pincer like Cu(II) complex as a pre‐catalyst, alcohol oxidation reaction without N‐oxide is explored. This was very active for the of benzyl alcohol. The best catalytic activity observed with 1 mmol alcohol, 4 mol% 20 KO t Bu in toluene at 70 °C 24 h. Both primary well secondary alcohols were successfully oxidized. It found that, protocol more efficient (5–12 h time) than (∼24 h). by can be switched N‐oxides 2,2,6,6‐tetramethylpiperidinyloxy (TEMPOH) 9‐azabicyclo[3.3.1]nonane N ‐Oxyl (ABNOH). mechanism studied UV–vis, EPR X‐ray photoelectron spectral studies. Thus, versatile showed good functional group tolerance substitutions on aromatic alcohols. Aerial oxygen acted sole oxidant cooperation / Cu(I) redox events. exhibited switchable behavior presence N‐oxide. Though Cu‐complex catalyzed explored, such where occurs containing inert ligand cocatalyst scarce.

Language: Английский