Spectroscopic characterization and quantum-chemical analysis of hydrazinyl thiazol-4(5H)-one functionalized materials to predict their key electronic and non-linear optical behavior.

• Synthesis of hydrazinylthiazol-4(5 H)-one derivatives (EHT1-EHT5) is done by condensation reaction. • Structures were analyzed through different spectroscopic techniques. • The experimental results show good agreement with theoretical results. • NLO and electronic properties were also studied. Organic chromophores are desirable as efficient nonlinear optical (NLO) substances because of their structural tunability, easy synthesis and promising NLO response. Herein, we synthesized series of organic compounds (EHT1-EHT5) containing hydrazinylthiazol-4(5 H)-one (HT) as a base and explored their nonlinear optical (NLO) properties through quantum chemical investigations. Novel hydrazinylthiazol-4(5 H)-ones were synthesized via two step synthetic approach. The synthesized structures were initially solved by different spectroscopic techniques. The authentication of the prepared structures was achieved with high resolution mass spectrometry (HRMS). Density functional theory (DFT) studies were executed at M06/6–311 G (d,p) functional. The optimized structures were used to perform further analysis including frontier molecular orbitals (FMOs), UV- Visible (UV–Vis), natural bond orbitals (NBOs), density of states (DOS), transition density matrix (TDM) along with nonlinear optical (NLO) characteristics. The quantum chemical insights led towards minimum E gap (4.797 eV) for EHT3 among all the compounds. Additionally, the outcomes of FMOs analysis were also supported by density of state (DOS) which further elucidated the proficient charge transference between HOMO and LUMO. The NBOs analysis revealed that all compounds had promising push-pull process through the existence of electron-accepting as well as donating groups. UV–Vis analysis indicated that all the investigated compounds (EHT1-EHT5) showed absorption wavelengths in the UV–Vis region, ranging from 290.1 to 303.7 nm. Among all these examined compounds (EHT1-EHT5), EHT3 displayed the highest value of λ max (303.717 nm) owing to its minimum band gap (4.028 eV). Furthermore, maximum values of first and second-order hyperpolarizabilities (β t o t and γ t o t ) were achieved for EHT3 as 7.756, 3.029 × 10−23 and 6.984 × 10−35 esu, respectively. In summary, our investigation provides new insights for the potential use of HT- based organic compounds (EHT1-EHT5) in future NLO applications. [ABSTRACT FROM AUTHOR]