Non-Switching 1,2-Dithienylethene-based Diplatinum(II) Complex Showing High Cytotoxicity

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• 作者：Andreu Presa ; Leoní Barrios ; Jordi Cirera ; Luís Korrodi-Gregório ; Ricardo Pérez-Tomás ; Simon J. Teat ; Patrick Gamez
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：June 6, 2016
• 年：2016
• 卷：55
• 期：11
• 页码：5356-5364
• 全文大小：395K
• 年卷期：0
• ISSN：1520-510X

文摘

A diplatinum(II) complex was prepared from a new 1,2-dithienylethene-based ligand containing N-methylimidazole groups as metal-binding units. Reaction of the ligand 1,2-bis[2-methyl-5-(1-methyl-1H-imidazol-2-yl)-3-thienyl]-cyclopentene (L2^H) with cis-dichlorobis(dimethylsulfoxido)platinum(II) generated the bimetallic complex trans-[Pt₂Cl₄(DMSO)₂(L2^H)] (DMSO = dimethyl sulfoxide), whose DNA-interacting properties were investigated using different techniques. Cytotoxicity assays with various cancer cell lines showed that this compound is active, with IC₅₀ values in the micromolar range. Surprisingly, the diplatinum(II) complex does not exhibit the anticipated photoswitching properties; indeed, UV irradiation does not lead to the photocyclization of the ligand L2^H or of the metal complex. Computational studies were performed and revealed significant differences in the electronic structure of L2^H compared with L1^H (i.e., 1,2-bis[2-methyl-5-(4-pyridyl)-3-thienyl]-cyclopentene, which exhibits photoswitching properties), in terms of the relevant molecular orbitals involved in the UV–vis absorption features, which ultimately is responsible for the inertia of L2^H toward photocyclization.