In a bid to come up with potential anticancer agents, a class of thiosemicarbazone ligands bearing substituted thiophene were synthesized followed by complexation with various Pd(II) and Pt(II) metal precursors. The ligands (E)-1-((thiophen-2-yl)methylene)thiosemicarbazide (L1), (E)-1-((4-bromothiophen-2-yl)methylene)thiosemicarbazide (L2), and (E)-1-((5-bromo thiophen-2-yl)methylene)thiosemicarbazide (L3) were synthesized by condensation reactions and obtained in good yields. Complexation of L1 and L2 with Pd(cod)Cl2 gave C1 (C6H7Cl2N3PdS2) and C2 (C6H6BrCl2N3PdS2), respectively. Complexation of L1 with K2PtCl4 gave C3 (C6H7Cl2N3PtS2), while L3 with K2PtCl2[(PPh)3]2 gave C4 (C24H21BrClN3PPtS2). The structures and coordination for all compounds were established by FTIR, 1H-NMR, 13C-NMR, UV-Vis, elemental analysis, and single-crystal X-ray diffraction studies for ligand L1. Tuning of the spectral and anticancer activity of the compounds was investigated by changing the position of the bromide substituent, metal center, and the σ or π-donor/acceptor strength of the groups surrounding the metal center. The compounds had low to moderate anticancer potency with their spectral and structural properties correlating with the corresponding anticancer activity profiles. DNA binding modes were studied by spectroscopy and were comparable to known DNA intercalators. Structure-activity profiles were evident especially between C1 and C2 differing by the presence of a Br in position 5 of thiophene ring, which caused a remarkable increase in IC50 values, from 14.71 ± 0.016 (C1) to 43.08 ± 0.001(C2) in Caco-2 cells, 1.973 ± 0.048 (C1) to 59.56 ± 0.010 (C2) in MCF-7 cells, 16.65 ± 0.051 (C1) to 72.25 ± 0.003 (C2) in HeLa cells, 14.64 ± 0.037 (C1) to 94.34 ± 0.003 (C2) in HepG2, and 14.05 ± 0.042 (C1) to >100(C2) in PC-3 cells.

中文翻译：

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新型 Pd(II) 和 Pt(II) 缩硫脲复合物的合成、表征和 DNA 结合动力学：光谱、结构和抗癌评估

为了找到潜在的抗癌剂，合成了一类带有取代噻吩的缩氨基硫脲配体，然后与各种 Pd(II) 和 Pt(II) 金属前体络合。配体 (E)-1-((噻吩-2-基)亚甲基)氨基硫脲 (L1)、(E)-1-((4-溴噻吩-2-基)亚甲基)氨基硫脲 (L2) 和 (E) -1-((5-溴噻吩-2-基)亚甲基)氨基硫脲(L3)通过缩合反应合成并以良好的收率获得。L1 和 L2 与 Pd(cod)Cl2 的络合分别得到 C1 (C6H7Cl2N3PdS2) 和 C2 (C6H6BrCl2N3PdS2)。L1 与 K2PtCl4 络合得到 C3 (C6H7Cl2N3PtS2)，而 L3 与 K2PtCl2[(PPh)3]2 络合得到 C4 (C24H21BrClN3PPtS2)。所有化合物的结构和配位均通过 FTIR、1H-NMR、13C-NMR、UV-Vis、元素分析、和配体 L1 的单晶 X 射线衍射研究。通过改变溴化物取代基的位置、金属中心和金属中心周围基团的 σ 或 π 供体/受体强度，研究了化合物的光谱和抗癌活性的调整。这些化合物具有低至中等的抗癌效力，其光谱和结构特性与相应的抗癌活性谱相关。DNA 结合模式通过光谱学进行研究，并且与已知的 DNA 嵌入剂相当。结构-活性谱在 C1 和 C2 之间尤其明显，不同之处在于噻吩环的第 5 位存在 Br，这导致 IC50 值显着增加，从 Caco 中的 14.71 ± 0.016 (C1) 到 43.08 ± 0.001(C2) -2 细胞，MCF-7 细胞中的 1.973 ± 0.048 (C1) 至 59.56 ± 0.010 (C2)，