Jayakumar S, Mahendiran D, Srinivasan T, Mohanraj G, Kalilur Rahiman A
Post-Graduate and Research Department of Chemistry, The New College (Autonomous), Chennai 600 014, India.
Department of Physics, Vel Tech University, Chennai 600 062, India.
J Photochem Photobiol B. 2016 Feb;155:66-77. doi: 10.1016/j.jphotobiol.2015.11.013. Epub 2015 Dec 12.
The reaction of soft tripodal scorpionate ligand, sodium hydrotris(methimazolyl)borate with M(ClO4)2·6H2O [MMn(II), Ni(II), Cu(II) or Zn(II)] in methanol leads to the cleavage of B-N bond followed by the formation of complexes of the type M(MeimzH)42·H2O (1-4), where MeimzH=methimazole. All the complexes were fully characterized by spectro-analytical techniques. The molecular structure of the zinc(II) complex (4) was determined by X-ray crystallography, which supports the observed deboronation reaction in the scorpionate ligand with tetrahedral geometry around zinc(II) ion. The electronic spectra of complexes suggested tetrahedral geometry for manganese(II) and nickel(II) complexes, and square-planar geometry for copper(II) complex. Frontier molecular orbital analysis (HOMO-LUMO) was carried out by B3LYP/6-31G(d) to understand the charge transfer occurring in the molecules. All the complexes exhibit significant antimicrobial activity against Gram (-ve) and Gram (+ve) bacterial as well as fungal strains, which are quite comparable to standard drugs streptomycin and clotrimazole. The copper(II) complex (3) showed excellent free radical scavenging activity against DPPH in all concentration with IC50 value of 30μg/mL, when compared to the other complexes. In the molecular docking studies, all the complexes showed hydrophobic, π-π and hydrogen bonding interactions with BSA. The cytotoxic activity of the complexes against human hepatocellular liver carcinoma (HepG2) cells was assessed by MTT assay, which showed exponential responses toward increasing concentration of complexes.
软三脚架型蝎形配体三（甲巯咪唑基）硼氢化钠与M(ClO4)2·6H2O [M = Mn(II)、Ni(II)、Cu(II) 或 Zn(II)] 在甲醇中反应，导致B-N键断裂，随后形成 M(MeimzH)42·H2O 型配合物（1-4），其中MeimzH = 甲巯咪唑。所有配合物均通过光谱分析技术进行了全面表征。通过X射线晶体学确定了锌（II）配合物（4）的分子结构，这支持了蝎形配体中观察到的脱硼反应以及锌（II）离子周围的四面体几何结构。配合物的电子光谱表明锰（II）和镍（II）配合物为四面体几何结构，铜（II）配合物为平面正方形几何结构。通过B3LYP/6-31G(d) 进行前沿分子轨道分析（HOMO-LUMO）以了解分子中发生的电荷转移。所有配合物对革兰氏阴性和革兰氏阳性细菌以及真菌菌株均表现出显著的抗菌活性，与标准药物链霉素和克霉唑相当。与其他配合物相比，铜（II）配合物（3）在所有浓度下对DPPH均表现出优异的自由基清除活性，IC50值为30μg/mL。在分子对接研究中，所有配合物均与牛血清白蛋白表现出疏水、π-π和氢键相互作用。通过MTT法评估了配合物对人肝细胞肝癌（HepG2）细胞的细胞毒性活性，结果表明其对配合物浓度增加呈指数响应。
