New pyridyl-containing diarylamines were obtained via Cu-assisted reductive amination of the ortho-2-pyridylaryl boronic acids. Comparative analysis of the spectral and electrochemical data obtained for new diarylamines and their pyridyl-free counterparts revealed the intramolecular H-bond (IMHB) formation which significantly influences the properties of the amino group. The electron density at the N atom of the amino group is increased due to partial weakening of the N-H bond, although the BDE and activation energy for the H-atom abstraction is increased due to the chelating effect of two N atoms. The ortho-pyridyl-containing diarylamines are more prone to be oxidized as compared to their pyridyl-free counterparts; the shift in the oxidation potential values correlates with the strength of the intramolecular H-bonding which can be tuned by inserting substituents in the pyridyl or phenyl rings. The IMHB is reserved even in polar solvents having a significant H-acceptor ability (such as DMSO) but can be destroyed in methanol, testifying in favor of the dynamic nature of the H-bonding.

Polarographic reduction of the azines

Diarylamines with the neighboring pyridyl group: synthesis and modulation of the amine functionality via intramolecular H-bonding

http://link.springer.com/content/pdf/10.1007/BF00855278.pdf

Polarographic reduction of the azines

Citations

Diarylamines with the neighboring pyridyl group: synthesis and modulation of the amine functionality via intramolecular H-bonding

Hydrazones: Communication 34. Investigation of the electrochemical reduction of certain substituted benzalazines in aprotonic medium

Polarographische reduktion von azinen

Organic Ion Radicals in Synthesis

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