Synthesis, characterization, density functional theory (DFT) analysis, and mesomorphic study of new thiazole derivatives

This study focuses on synthesizing and characterizing a new series of organic compounds with a heterocyclic core based on sulfur (thiazole). These compounds, labeled as N-(4-(4-alkoxyphenyl) thiazol-2-yl)-1-(naphthalen-2-yl) methanimine (ATNM)n, incorporate alkoxy chains of varying lengths (CnH2n+1O, n = 2, 3, 4, 5, 6, 7, 8, 9, 10, and 12) through a multi-step process. Structural analysis using FT-IR, 1H-NMR, and 13C-NMR confirmed the composition of these compounds. Theoretical calculations using density functional theory (DFT) were carried out with the B3LYP 6-311G (d,p) basis set for the entire set of synthesized compounds (ATNM)n. The (Gaussian 9) software was employed to compute optimized geometrical structures of the proposed compounds in the gas phase. However, investigations into their phase behavior using polarizing optical microscopy (POM) and differential scanning calorimetry (DSC) revealed that none of the compounds in this series exhibited the typical mesomorphic characteristics of liquid crystals. Comparisons were made between theoretical predictions from DFT and observed data obtained through synthesized compounds study. The results revealed that the presence of terminal alkoxy significantly influenced the overall energy of potential geometric structures, along with their physical and thermal characteristics. KEY WORDS: Heterocyclic compounds, Thiazole, Liquid crystals, DFT, Methanimine Bull. Chem. Soc. Ethiop. 2024, 38(6), 1827-1842. DOI: https://dx.doi.org/10.4314/bcse.v38i6.25