Formazans and tetrazolium salts are two structurally related classes of organic compounds that form redox pairs with each other. They have broad application in biomedical research, and as specialty dyes, metal ligands and colorimetric indicators (e.g., for the dosimetry of ionizing radiation). The recent research interest has been focused primarily on formazans, including computational studies of their properties via density functional theory (DFT) and time-dependent DFT (TD-DFT). However, there are, to our knowledge, no computational studies of tetrazolium salts exist. To remedy this situation, we present a comparative DFT and TD-DFT study of eleven pairs of triaryl-substituted formazans and tetrazolium salts, containing phenyl, 4-nitrophenyl, 4-bromophenyl, 2-benzothiazolyl, 6-methoxy-2-benzothiazolyl and 1-naphthyl substituents. Following geometric optimization and selection of the most stable conformer (for formazans), we proceeded to examine the frontier molecular orbitals, global reactivity descriptors, molecular electrostatic potential maps and local reactivity, as well as vertical excitation energies and electronic spectra of the studied materials. Finally, through a comparison of reactivity and electronic spectra, we present a framework for the design of formazan – tetrazolium salt pairs that are suited for specific colorimetric applications.

甲and和四唑盐是彼此形成氧化还原对的两类结构相关的有机化合物。它们在生物医学研究中以及作为特种染料，金属配体和比色指示剂（例如，用于电离辐射的剂量测定）方面具有广泛的应用。最近的研究兴趣主要集中在甲maz，包括通过对其性质的计算研究。密度泛函理论（DFT）和时变DFT（TD-DFT）。然而，据我们所知，不存在四唑鎓盐的计算研究。为了纠正这种情况，我们对11对三芳基取代的甲and和四唑盐进行了DFT和TD-DFT对比研究，这些盐分别含有苯基，4-硝基苯基，4-溴苯基，2-苯并噻唑基，6-甲氧基-2-苯并噻唑基和1-萘基取代基。在进行几何优化和选择最稳定的构象异构体（对于甲maz）之后，我们着手研究了前沿分子轨道，整体反应性描述符，分子静电势图和局部反应性，以及研究材料的垂直激发能和电子光谱。最后，通过比较反应性和电子光谱，