Sonication-assisted synthesis of new Schiff bases derived from 3-ethoxysalicylaldehyde: Crystal structure determination, Hirshfeld surface analysis, theoretical calculations and spectroscopic studies

A rapid and efficient preparation of a new series of the Schiff bases (Pn) by the reaction of 2-aminopyridine derivatives with 3-ethoxysalicylaldehyde under ultrasonic irradiation is reported. Sono chemical synthesis is the safest and greener method for the preparation of Schiff bases in the shorter period of time with higher yield as compared to traditional methods. The synthesized compounds have been characterized by H-1 NMR spectroscopic technique and elemental analyses. Furthermore, the crystal structures of two compounds (P0 and P6 ) were determined by single crystal X-ray diffraction studies. Hirshfeld surface analysis showed that H center dot center dot center dot H interatomic contact is the most significant contributor in crystal packing of both compounds with percentage contribution of 53.7% and 57.7% for P0 and P6 , respectively. Theoretical calculations of the synthesized compounds were carried out by DFT using B3LYP method with the help of Def2-TZVP basis set, indicating that the results of calculation are in accordance with the experimental findings. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

A new series of Schiff bases (Pn) were rapidly and efficiently prepared using ultrasonic irradiation. The synthesized compounds were characterized by NMR and elemental analyses, with crystal structures of some compounds determined by X-ray diffraction. Hirshfeld surface analysis revealed the significant contribution of H···H interatomic contact in crystal packing. Theoretical calculations using DFT confirmed the experimental findings.