Haque Imdadul, Enamullah Mohammed, Resma Amina Khan, Jhumur Nisat Taslum, Woschko Dennis, Mohabbat Abdulrahman, van Leusen Jan, Kögerler Paul, Janiak Christoph
Department of Chemistry, Jahangirnagar University, Dhaka, 1342, Bangladesh.
Institut für Anorganische Chemie und Strukturchemie, Universität Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany.
Chem Asian J. 2024 Dec 16;19(24):e202400915. doi: 10.1002/asia.202400915. Epub 2024 Oct 31.
Reaction of the phenolate or naphthalen-2-olate based Schiff base ligands, (E)-1-((2-ethylphenylimino)methyl)phenol (HL1) or (E)-1-((2-ethylphenylimino)methyl)naphthalen-2-ol (HL2) with nickel(II) and copper(II) acetate provides the complexes bis[(E)-1-((2-ethylphenylimino)methyl)phenolato-ĸN,O]Ni/Cu(II), [Ni(L1)] (1) and [Cu(L1)] (2), or bis[(E)-1-((2-ethylphenylimino)methyl)naphthalen-2-olato-ĸN,O]Ni/Cu(II), [Ni(L2)] (3) and [Cu(L2)] (4), respectively. Single crystal X-ray structure determinations for 1, 3 and 4 reveal N,O-metal coordination of two chelating Schiff base ligands in a square-planar geometry. Powder X-ray diffractograms confirm the phase purity of the bulk microcrystalline samples. Thermal analyses by differential scanning calorimetry (DSC) and polarized light microscopic (PLM) indicate the copper(II) complexes to exhibit cold crystal (2) and liquid crystal (4) property. Cyclic voltammograms suggest an irreversible electrochemical process with two one electron charge transfer processes in N,N-dimethylformamide. Variable temperature magnetic measurements at the solid-state prove the diamagnetic nature of the low-spin Ni centres in 1 or 3, as expected from the square-planar coordination geometry with rather strong ligands. The complexes expose medium level of antioxidant activity in methanol. Optimized geometry and excited state property by DFT/TD-DFT correspond well to the experimental results of the electronic and molecular structure at the ground state.
基于酚盐或萘 - 2 - 酚盐的席夫碱配体，即（E）-1 - （（2 - 乙基苯基亚氨基）甲基）苯酚（HL1）或（E）-1 - （（2 - 乙基苯基亚氨基）甲基）萘 - 2 - 醇（HL2）与醋酸镍（II）和醋酸铜（II）反应，分别得到配合物双[（E）-1 - （（2 - 乙基苯基亚氨基）甲基）苯酚根 - κN，O]镍/铜（II），[Ni（L1）]（1）和[Cu（L1）]（2），或双[（E）-1 - （（2 - 乙基苯基亚氨基）甲基）萘 - 2 - 醇根 - κN，O]镍/铜（II），[Ni（L2）]（3）和[Cu（L2）]（4）。对1、3和4进行的单晶X射线结构测定揭示了两个螯合席夫碱配体以平面正方形几何构型进行N，O - 金属配位。粉末X射线衍射图证实了块状微晶样品的相纯度。通过差示扫描量热法（DSC）和偏光显微镜（PLM）进行的热分析表明，铜（II）配合物具有冷结晶（2）和液晶（4）性质。循环伏安图表明在N，N - 二甲基甲酰胺中存在一个不可逆的电化学过程以及两个单电子电荷转移过程。固态变温磁性测量证明了1或3中低自旋Ni中心的抗磁性，这与具有相当强配体的平面正方形配位几何构型所预期的一致。这些配合物在甲醇中表现出中等水平的抗氧化活性。通过DFT/TD-DFT优化的几何结构和激发态性质与基态电子和分子结构的实验结果吻合良好。
