Molecular engineering of multifunctional benzothiazole-sulfonamide hybrids: from synthesis to optoelectronic applications

This study presents the design and comprehensive characterization of innovative benzothiazole–sulfonamide molecular hybrids 6a–e, specifically engineered to exhibit tunable optoelectronic and electrochemical properties crucial for advanced materials applications. Synthesized through a molecular hybridization approach, these compounds were rigorously characterized using FTIR, NMR, and mass spectrometry. UV–Vis spectroscopy revealed strong absorption between 295–422 nm, with optical band gaps ranging from 2.45–2.95 eV, indicating their potential as light-harvesting components. Photoluminescence studies demonstrated substituent-dependent emission intensities, with the thiazole-containing hybrid 6b exhibiting the highest relative emission intensity, highlighting its promise for emissive applications. Thermogravimetric analysis (TGA) confirmed the outstanding thermal performance of these compounds, with decomposition temperatures spanning 144–307 °C, notably with the pyrimidine-substituted derivative 6c displaying the highest thermal stability, a critical factor for device longevity. Electrochemical evaluation via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) elucidated the profound influence of molecular structure on redox behavior and charge transfer kinetics. The derived HOMO levels, ranging from − 5.18 to − 5.45 eV, alongside 6c’s lowest charge transfer resistance (R_ct = 68.4 kΩ) and most reversible redox behavior, underscore their suitability as charge transport materials. A strong correlation was established between thermal stability, electrochemical performance, and optical properties, demonstrating that planar, conjugated systems (e.g., 6c) significantly outperform sterically hindered derivatives (e.g., 6e). These findings unequivocally illustrate the potential of benzothiazole-sulfonamide hybrids as versatile and tunable materials for diverse optoelectronic applications, including high-performance organic semiconductors, chemical sensors, and efficient energy storage devices.