Facile Synthesis and DFT Analysis of Novel Thiazole-Based Hydrazones: An Experimental and Theoretical Perspective

[Image: see text] Hydrazone compounds with remarkable nonlinear optical (NLO) properties were found with vast applications due to their cost-effective synthesis and greater stability. Therefore, we synthesized hydrazone scaffolds (TCAH1–TCAH8) by condensation reaction, and their structural confirmation was accomplished with spectroscopic methods ((1)H-, (13)C-NMR, and HRMS). Quantum chemical calculations were also performed at B3PW91/6-311G(d,p) functional of DFT to explore electronic, structural, and chemical properties. To understand the NLO responses of afore-said chromophores, various kinds of analyses such as natural bonding orbitals (NBOs), frontier molecular orbitals (FMOs), UV–vis analysis, and density of states (DOS) were performed. Findings showed that the HOMO–LUMO energy gap in TCAH8 (3.595 eV) was found to be lower than the TCAH1–TCAH7 (4.123–3.932 eV) with a large red shift which leads to a substantial NLO response. Furthermore, strong intramolecular interactions showed the highest stabilization energy (24.1 kcal mol(–1)) for TCAH8 in the NBO transitions, combined with the least binding energy. The significant NLO response of TCAH4 was explored with ⟨α⟩, β(tot), and ⟨γ⟩ values as 5.157 × 10(–23), and 2.185 × 10(–29), and 2.753 × 10(–34) esu, respectively, among the entitled compounds. The recent findings may inspire scientists to develop extremely effective NLO materials for forthcoming hi-tech applications.