Hydrazones have attracted considerable interest for their antimicrobial and nonlinear optical (NLO) applications. In the present work, a new hydrazone (E)-N′-(4-isopropylbenzylidene)nicotinohydrazide (INH) was synthesized by a condensation reaction of cuminaldehyde with nicotinic hydrazide via ultrasonication. The hydrazone was characterized by FT-IR spectroscopy, mass spectrometry, NMR (¹H, ¹³C, HOMO-COSY, HSQC, and DEPT-135), elemental analysis, and FESEM analyses. Phase-pure and non-existent isomorphic phase transition in INH was demonstrated by X-ray diffraction and thermogravimetric analysis. The absorption maximum of INH in an aqueous solution was red-shifted compared to that of the reactant molecules, indicating that the CN bond formation efficiently enhances the resonance interaction towards the pyridine ring. Fluorescence emission of INH at a shorter wavelength is caused by a locally excited state. A longer wavelength band is caused by intramolecular proton transfer in nonpolar/aprotic solvents, while it is caused by TICT emission in protic solvents. The direct and indirect bandgaps of the INH crystals were assessed using Tauc plots and the Kubelka–Munk algorithm. The efficacy of INH for the inactivation of E. coli and B. subtilis were examined through a plate colony counting assay, and the inactivation was 62.7 ± 0.2 % and 98.3 ± 0.4 %, respectively. The geometrical structure, Mulliken, MEP surface, and electronic properties of INH are theoretically optimized using density functional theory (DFT) at the B3LYP/6-31G(d,p) level and showed good concurrence with the experimentally defined structure. The INH displays higher NLO properties compared to urea as a reference, as determined by molecular hyperpolarizability analysis. The frontier molecular orbitals and global reactivity descriptors showed that INH is more reactive and reasonably stable.

腙因其抗菌和非线性光学 (NLO) 应用而引起了人们的极大兴趣。在目前的工作中，一种新的腙 ( E )-N ' -(4-isopropylbenzylidene)nicotinohydrazide (INH) 通过超声处理对异丙苯醛与烟酰肼进行缩合反应合成。^{腙通过 FT-IR 光谱、质谱、NMR（ 1} H、¹³ C、HOMO-COSY、HSQC 和 DEPT-135）、元素分析和 FESEM 分析来表征。通过 X 射线衍射和热重分析证明了 INH 中的纯相和不存在的同晶相变。与反应物分子相比，INH 在水溶液中的吸收最大值发生红移，表明 CN键的形成有效地增强了对吡啶环的共振相互作用。INH 在较短波长处的荧光发射是由局部激发态引起的。较长的波长带是由非极性/非质子溶剂中的分子内质子转移引起的，而它是由质子溶剂中的 TICT 发射引起的。使用 Tauc 图和 Kubelka–Munk 算法评估 INH 晶体的直接和间接带隙。INH 灭活大肠杆菌和枯草芽孢杆菌的功效通过平板菌落计数法检测，灭活率分别为 62.7 ± 0.2 % 和 98.3 ± 0.4 %。INH 的几何结构、Mulliken、MEP 表面和电子特性在 B3LYP/6-31G(d,p) 水平上使用密度泛函理论 (DFT) 进行了理论上的优化，并与实验定义的结构表现出良好的一致性。与作为参考的尿素相比，INH 显示出更高的 NLO 特性，这由分子超极化分析确定。前沿分子轨道和全局反应性描述符表明 INH 更具反应性且相当稳定。