In this work, we present the synthesis, characterization, electrochemical studies, DFT calculations, and in vitro amoebicidal effect of seven new heteroleptic NiII coordination compounds. The crystal structures of [H2(pdto)](NO3)2 and [Ni(pdto)(NO3)]PF6 are presented, pdto = 2,2'-[1,2-ethanediylbis-(sulfanediyl-2,1-ethanediyl)]dipyridine. The rest of the compounds have general formulae: [Ni(pdto)(NN)](PF6) where N-N = 2,2'-bipyridine (bpy), 4,4'-dimethyl-2,2'-bipyridine (44dmbpy), 5,5'-dimethyl-2,2'-bipyridine (55dmbpy), 1,10-phenanthroline (phen), 4,7-dimethyl-1,10-phenanthroline (47dmphen) and 5,6-dimethyl-1,10-phenanthroline (56dmphen). The size of NN ligand and its substituents modulate the compound electronic features and influence their antiproliferative efficiency against Entamoeba histolytica. 56dmphen derivative, shows the biggest molar volume and presents a powerful amoebicidal activity (IC50 = 1.2 μM), being seven times more effective than the first-line drug for human amoebiasis metronidazole. Also, increases the reactive oxygen species concentration within the trophozoites. This could be the trigger of the E. histolytica growth inhibition. The antiparasitic effect is described using NiII electron density, molar volume, estimated by DFT, as well as the experimental redox potential and diffusion coefficients. In general, amoebicidal efficiency is directly proportional to the increment of the molar volume and decreases when the redox potential becomes more positive.

中文翻译：

---

NiII杂配物：合成，结构表征，计算研究和杀螨活性评估。

在这项工作中，我们介绍了七种新的杂合NiII配位化合物的合成，表征，电化学研究，DFT计算和体外杀菌作用。给出了[H2（pdto）]（NO3）2和[Ni（pdto）（NO3）] PF6的晶体结构，pdto = 2,2'-[1,2-乙二基双-（亚砜二基-2,1-乙二基） ）]双吡啶。其余化合物的通式为：[Ni（pdto）（NN）]（PF6）其中NN = 2,2'-联吡啶（bpy），4,4'-二甲基-2,2'-联吡啶（44dmbpy） ，5,5'-二甲基-2,2'-联吡啶（55dmbpy），1,10-菲咯啉（phen），4,7-二甲基-1,10-菲咯啉（47dmphen）和5,6-二甲基-1， 10-菲咯啉（56dmphen）。NN配体及其取代基的大小可调节化合物的电子特征，并影响其对解组织变形虫的抗增殖效率。56dmphen衍生物，显示出最大的摩尔体积，并具有强大的杀螨活性（IC50 = 1.2μM），是用于人类阿米巴病甲硝唑的一线药物的七倍强。同样，增加了滋养体中活性氧的浓度。这可能是溶组织性大肠杆菌生长抑制的触发因素。使用NiII电子密度，通过DFT估算的摩尔体积以及实验性氧化还原电势和扩散系数来描述抗寄生效应。通常，杀生效率与摩尔体积的增加成正比，而当氧化还原电势变得更正时则降低。增加了滋养体中活性氧的浓度。这可能是溶组织性大肠杆菌生长抑制的触发因素。使用NiII电子密度，通过DFT估算的摩尔体积以及实验性氧化还原电势和扩散系数来描述抗寄生效应。通常，杀生效率与摩尔体积的增加成正比，而当氧化还原电势变得更正时则降低。增加了滋养体中活性氧的浓度。这可能是溶组织性大肠杆菌生长抑制的触发因素。使用NiII电子密度，通过DFT估算的摩尔体积以及实验性氧化还原电势和扩散系数来描述抗寄生效应。通常，杀生效率与摩尔体积的增加成正比，而当氧化还原电势变得更正时则降低。