Density functional calculations were used to explore the complexation of 3-alkyl-4-phenylacetylamino-4,5-dihydro-1h-1,2,4-triazol-5-one (ADPHT) derivatives by first-row transition metal cations. Neutral ADPHT ligand and mono deprotonated ligands have been used. Geometry optimizations have been performed in gas-phase and solution-phase (water, benzene, and N,N-dimethylformamide (DMF)) with B3LYP/Mixed I (LanL2DZ for metal atom and 6-31+G(d,p) for C, N, O, and H atoms) and with B3LYP/Mixed II (6-31G(d) for metal atom and 6-31+G(d,p) for C, N, O, and H atoms) especially in the gas-phase. Single points have also been carried out at CCSD(T) level. The B3LYP/Mixed I method was used to calculate thermodynamic energies (energies, enthalpies, and Gibb energies) of the formation of the complexes analyzed. The B3LYP/Mixed I complexation energies in the gas phase are therefore compared to those obtained using B3LYP/Mixed II and CCSD(T) calculations. Our results pointed out that the deprotonation of the ligand increases the binding affinity independently of the metal cation used. The topological parameters yielded from Quantum Theory of Atom in Molecules (QTAIM) indicate that metal-ligand bonds are partly covalent. The significant reduction of the proton affinity (PA) observed when passing from ligands to complexes in gas-phase confirms the notable enhancement of antioxidant activities of neutral ligands.

中文翻译：

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通过DFT研究通过3-烷基-4-苯基乙酰氨基-4,5-二氢-1H-1,2,4-三唑-5酮及其衍生物从第一行过渡金属螯合获得的配合物的结构和键合性质。

密度泛函计算用于探索第一行过渡金属阳离子与3-烷基-4-苯基乙酰氨基-4,5-二氢-1h-1,2,4-三唑-5-酮（ADPHT）衍生物的络合。已经使用中性ADPHT配体和单去质子化的配体。在气相和溶液相（水，苯和N，N-二甲基甲酰胺（DMF））中使用B3LYP /混合I（对于金属原子为LanL2DZ，对于金属原子为1-31 + G（d，p））进行了几何优化。 C，N，O和H原子）和B3LYP /混合II（金属原子为6-31G（d），C，N，O和H原子为6-31 + G（d，p）），尤其是在气相。单点也已在CCSD（T）级别进行。B3LYP /混合I方法用于计算所分析的配合物形成的热力学能量（能量，焓和吉布能）。因此，将气相中的B3LYP /混合I络合能与使用B3LYP /混合II和CCSD（T）计算获得的能相比较。我们的结果指出，配体的去质子增加了与所用金属阳离子无关的结合亲和力。从分子的原子量子理论（QTAIM）得到的拓扑参数表明，金属-配体键是部分共价的。在气相中从配体传递到络合物时，所观察到的质子亲和力（PA）显着降低，证实了中性配体的抗氧化活性显着增强。从分子的原子量子理论（QTAIM）得到的拓扑参数表明，金属-配体键是部分共价的。当在气相中从配体传递到络合物时，所观察到的质子亲和力（PA）显着降低，证实了中性配体的抗氧化活性显着增强。从分子的原子量子理论（QTAIM）得到的拓扑参数表明，金属-配体键是部分共价的。当在气相中从配体传递到络合物时，所观察到的质子亲和力（PA）显着降低，证实了中性配体的抗氧化活性显着增强。