Abstract

A series of tridentate ONS Schiff bases were synthesised via condensation by reacting 2,3-dihydroxybenzaldehyde with S-2-methylbenzyldithiocarbazate (S2MBDTC) (1), S-4-methylbenzyldithiocarbazate (S4MBDTC) (2) and S-benzyldithiocarbazate (SBDTC) (3) in an equimolar ratio (10 mmol). The Schiff bases were then reacted with diphenyltin(IV) and dimethyltin(IV) dichloride in an equimolar ratio (1 mmol) yielding six new organotin(IV) compounds (4–9). All the compounds were successfully characterised by elemental analysis, FT-IR, multinuclear NMR, UV–Vis, mass spectroscopy and molar conductivity. The molecular geometries for five compounds, 3, 5, 6, 8 and 9, have been established by X-ray crystallography. The five-coordinate geometry for each of the diorganotin molecules was defined by two carbon atoms from the tin-bound substituents as well as three donor atoms derived from the dinegative, tridentate dithiocarbazate ligands, namely thiolate-S, phenoxide-O and imine-N atoms. The resultant five-coordinate C₂NOS geometries were intermediate between ideal square pyramidal and trigonal bipyramidal geometries. The diphenyltin(IV) compounds (4–6) exhibited particularly promising and selective cytotoxicity against the A2780 (ovarian), BE2-C (neuroblastoma), SJ-G2 (glioblastoma) and MIA (pancreas) cancer cell lines. The interactions of the compounds (4–9) with calf thymus (CT-DNA) were evaluated using an electronic absorption method, and 7, 8, 9 were found to have good DNA binding affinity. The molecular docking studies of compounds (4–9) with DNA revealed that the compounds interacted with duplex DNA via hydrogen bonding, hydrophobic and electrostatic interactions.

Graphic abstract

摘要

通过使2,3-二羟基苯甲醛与S-2-甲基苄基二硫代咔唑酸酯（S2MBDTC）（1），S-4-甲基苄基二硫代咔唑酸酯（S4MBDTC）（2）和S-苄基二硫代咔唑酸酯（SBDTC）（3）以等摩尔比（10mmol）。然后使席夫碱与二苯基锡（IV）和二氯化二甲基锡（IV）以等摩尔比（1 mmol）反应，生成六种新的有机锡（IV）化合物（4 – 9）。所有化合物均通过元素分析，FT-IR，多核NMR，UV-Vis，质谱和摩尔电导率成功表征。对于五种化合物，分子几何结构3，5，6，8和9，已经通过X射线晶体学确定。每个二有机锡分子的五坐标几何结构由锡键合取代基中的两个碳原子以及衍生自负三齿二硫代氨基甲酸酯配体的三个供体原子定义，即硫醇盐-S，酚盐-O和亚胺基-N原子。所得的五坐标C ₂ NOS几何形状介于理想的方形金字塔形和三角形双锥体几何形状之间。的二苯基（IV）的化合物（4 - 6）表现出特别有前途并抵靠A2780（卵巢）选择性细胞毒性，BE2-C（神经母细胞瘤），SJ-G2（成胶质细胞瘤）和MIA（胰腺）的癌细胞系。化合物之间的相互作用（4 - 9）与小牛胸腺（CT-DNA）的使用电子吸收法评价，7，8，9被发现具有良好的DNA结合亲和力。化合物（4 – 9）与DNA的分子对接研究表明，这些化合物通过氢键，疏水和静电相互作用与双链DNA相互作用。

图形摘要