Lawrence Mark A W
Department of Chemistry, The University of the West Indies Mona, Kingston 7, W.I., Jamaica.
J Mol Model. 2024 Jul 31;30(8):294. doi: 10.1007/s00894-024-06082-0.
Hydrazones have been studied for a myriad of chemical and physiochemical properties, such as sensors, chelators and numerous biological activities. Experimental data indicates that hydrazones are unstable under cathodic potentials irrespective of the solvent. The single electron reduction of hydrazones to produce radical anions result in unstable species that cleaves at the N-N bond in a heterolytic manner. The literature has proposed a mechanism favouring the radical on the imine moiety, however in this study DFT calculations suggest the radical on the amine product is more likely upon bond cleavage. This has implications on electrochemical mechanisms, and the active molecule in biological studies viz the method of delivery to target areas.
Density functional theory calculations were carried out using the GAMESS software package. The structures were optimized in the gas phase (B3LYP/6-31G(d,p)) as indicated by the absence of imaginary frequencies in the Hessian, and in CHCN (B3LYP/6-31G(d,p)/SMD) with the Pople polarization functions. As a comparison, selected pathways were fully optimized using PBE0/6-31G(d,p) and PBE0/6-31G(d,p)/SMD for gas phase and CHCN, respectively with the Pople polarization functions. The values were not significantly different (< 5% difference). As such only the B3LYP is evaluation is discussed.
腙因其众多化学和物理化学性质而受到研究，例如传感器、螯合剂以及多种生物活性。实验数据表明，无论溶剂如何，腙在阴极电位下都不稳定。腙单电子还原生成自由基阴离子会产生不稳定物种，该物种会以异裂方式在N-N键处断裂。文献提出了一种有利于亚胺部分产生自由基的机制，然而在本研究中，密度泛函理论计算表明，键断裂后胺产物上的自由基更有可能产生。这对电化学机制以及生物学研究中的活性分子，即向靶区域的递送方法都有影响。
使用GAMESS软件包进行密度泛函理论计算。结构在气相中（B3LYP/6-31G(d,p)）进行优化，如黑塞矩阵中无虚频所示，在CHCN中（B3LYP/6-31G(d,p)/SMD）使用普适极化函数进行优化。作为比较，分别使用PBE0/6-31G(d,p)和PBE0/6-31G(d,p)/SMD对气相和CHCN中的选定路径进行完全优化，均使用普适极化函数。这些值差异不显著（差异<5%）。因此，仅讨论B3LYP的评估。
