Herein is presented a density functional theory (DFT) study of reactivity and structural properties of transition metal complexes of the Schiff base ligand 2,2′(1E,1′E)-(ethane-1,2-diylbis(azan-1-yl-1-ylidene))bis(phenylmethan-1-yl-1-ylidene)dibenzoic acid (hereafter denoted EDA2BB) with Cu(II), Mn(II), Ni(II), and Co(II). The quantum theory of atoms-in-molecules (QTAIM), conceptual DFT, natural population analysis (NPA), and molecular electrostatic potential (MEP) methods have been used. Results have revealed a distorted octahedral geometry around the central metal ion in each gas phase complex. In the DMSO solvent, a general axial elongation of metal-oxygen bonds involving ancillary water ligands has been observed, suggestive of loosely bound water molecules to the central metal ion that may be acting as solvent molecules. Weak, medium, and strong intramolecular hydrogen bonds along with hydrogen-hydrogen and van der Waals interactions have been elucidated in the complexes investigated via geometric and QTAIM analyses. From the chemical hardness values, the complex [Co(EDA2BB)(OH₂)₂] is the hardest, while [Cu(EDA2BB)(OH₂)₂] is the softest. Based on the global electrophilicity index, the complexes [Ni(EDA2BB)(OH₂)₂] and [Cu(EDA2BB)(OH₂)₂] are the strongest and weakest electrophiles, respectively, among the complexes studied. In conclusion, the reactivity of the complexes is improved vis-à-vis the ligand, and stable geometries of the complexes are identified, alongside their prominent electrophilic and nucleophilic sites.

中文翻译：

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2,2'（1E，1'E）-（乙烷-1,2-二基双（氮杂-1-基-1-亚烷基））双（苯甲氧基-1-）的一些过渡金属配合物的结构性质和反应中心选择性yl-1-亚烷基）二苯甲酸：DFT，概念DFT，QTAIM和MEP研究。

本文介绍了密度泛函理论（DFT）对Schiff碱配体2,2'（1E，1'E）-（乙烷-1,2-二基双（Azan-1-）的过渡金属配合物的反应性和结构性质的研究（亚乙基-1-亚烷基））双（苯基亚甲基-1-基-1-亚烷基）二苯甲酸（以下称为EDA2BB）与Cu（II），Mn（II），Ni（II）和Co（II）。已经使用了分子中原子的量子理论（QTAIM），概念DFT，自然种群分析（NPA）和分子静电势（MEP）方法。结果表明，在每个气相络合物中，中心金属离子周围的八面体几何形状均发生了变形。在DMSO溶剂中，已经观察到涉及辅助水配体的金属-氧键的总体轴向伸长，这表明水分子与可能充当溶剂分子的中心金属离子松散结合。弱，中，通过几何和QTAIM分析研究了复合物中的强分子内氢键以及氢-氢和范德华相互作用。从化学硬度值来看，络合物[Co（EDA2BB）（OH₂）₂ ]最软，而[Cu（EDA2BB）（OH ₂）₂ ]最软。基于整体亲电指数，在所研究的配合物中，配合物[Ni（EDA2BB）（OH ₂）₂ ]和[Cu（EDA2BB）（OH ₂）₂ ]分别是最强和最弱的亲电体。总之，与配体相比，复合物的反应性得到了改善，并且鉴定了复合物的稳定几何形状，以及其突出的亲电和亲核位点。