Cover Feature: Versatility of the Amino Group in Hydrazone‐Based Molecular and Supramolecular Systems (Eur. J. Org. Chem. 28/2022)

Abstract

The Cover Feature highlights the Latin American culture with an emblem that is the accordion and how the versatility of the amino group resembles the musical notes that appropriately combined exhibit multiple dynamics in the hydrazones. Each highlighted hydrazone‐based system represents one type of dynamism: conformational (orange), configurational (blue), and constitutional (green). The harmonic box contains the words “amino group” to remark the particularly important role of the N–H group in each of those processes observed in hydrazone‐based molecular and supramolecular systems. The authors thank Alejandro Ijaji for the extraordinary design of the cover, following the concept given by the authors. More information can be found in the Review by M. N. Chaur et al.

Importance of the Amino Moiety of the Hydrazone Group in the Electrochemical and UV‐Vis Absorption Properties of Simple Isomeric Hydrazones

“…Column chromatography was performed for the separation of the configurational isomers using 230-400 mesh silica gel particles. 1 H, 13 C, and 2D NMR spectra were recorded on a Bruker Ultrashield 400 MHz NMR spectrometer. Chemical shifts are quoted in ppm using the residual solvent peak as the reference standard, with the abbreviation app.…”

“…On the other hand, the use of hydrazones as polydentate ligands makes them prominent in coordination chemistry since the acidity of the N−H group can be increased after coordination and then used to strengthen metal‐ligand bonds, which is useful in the preparation of homo‐ and heteronuclear grid‐like complexes, [11] and even to modify the magnetic properties of a metal center [12] . These facts suggest that the amino group of hydrazones is more important than it seems, [13] and even more so in solution, where its solvation could be decisive for those properties that, in a certain way, depend on the electron density around the nitrogen of the N−H group [8] . Taking all the above into account, in this work we study the UV‐Vis absorption and electrochemical properties of two isomeric hydrazones, which will be contrasted with those of the N ‐methylated derivate of 1‐E (see Figure 1), and evaluate the importance of the N−H group in their behavior in solution.…”

Transition metal(ii) complexes of halogenated derivatives of (E)-4-(2-(pyridin-2-ylmethylene)hydrazinyl)quinazoline: structure, antioxidant activity, DNA-binding DNA photocleavage, interaction with albumin andin silicostudies

“…[5][6][7][8][9][10] Hydrazones contain a characteristic R 1 R 2 CvN-NHR 3 functional group which due to its isomerization and nucleophilic, electrophilic and acidic sites gives rise to versatile uses of their carrier compounds. [10][11][12][13] In conjunction with well-situated electron donors, hydrazones are capable of forming metal complexes which were found to exhibit catalytic [14][15][16][17] and biological activities. [18][19][20][21] Although 4-quinazoline-hydrazone derivatives fulfill the structural criteria for metal coordination, very few derivatives are found in the literature.…”