Dinuclear platinum(II) complexes, [{Pt(en)Cl}₂(-qx)]Cl₂·2H₂O (1), [{Pt(en)Cl}₂(-qz)](ClO₄)₂ (2), and [{Pt(en)Cl}₂(-phtz)]Cl₂·4H₂O (3), were synthesized and characterized by different spectroscopic techniques. The crystal structure of 1 was determined by single-crystal X-ray diffraction analysis, while the DFT M06-2X method was applied in order to optimize the structures of 1–3. The chlorido Pt(II) complexes 1–3 were converted into the corresponding aqua species 1a–3a, and their reactions with an equimolar amount of Ac–L–Met–Gly and Ac–L–His–Gly dipeptides were studied by ¹H NMR spectroscopy in the pH range 2.0 < pH < 2.5 at 37°C. It was found that, in all investigated reactions with the Ac–L–Met–Gly dipeptide, the cleavage of the Met–Gly amide bond had occurred, but complexes 2a and 3a showed lower catalytic activity than 1a. However, in the reactions with Ac–L–His–Gly dipeptide, the hydrolysis of the amide bond involving the carboxylic group of histidine was observed only with complex 1a. The observed disparity in the catalytic activity of these complexes is thought to be due to different relative positioning of nitrogen atoms in the bridging qx, qz, and phtz ligands and consequent variation in the intramolecular separation of the two platinum(II) metal centers.

中文翻译：

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以苯并二嗪作为桥连配体的双核铂 (II) 配合物促进含甲硫氨酸和组氨酸的肽的水解：配体结构对铂 (II) 配合物催化能力的影响。


双核铂(II)络合物, [{Pt(en)Cl} ₂ (-qx)]Cl ₂ ·2H ₂ O ( 1 ), [{Pt(en)Cl} ₂ (-qz)](ClO ₄ ) ₂ ( 2 ) 和[{Pt(en)Cl} ₂ (-phtz)]Cl ₂ ·4H ₂ O ( 3 ) 被合成并通过不同的光谱技术进行表征。通过单晶X射线衍射分析确定了1的晶体结构，同时应用DFT M06-2X方法优化了1-3的结构。将氯化 Pt(II) 配合物1-3转化为相应的水族1a-3a ，并通过¹ H 研究了它们与等摩尔量的 Ac-L-Met-Gly 和 Ac-L-His-Gly 二肽的反应。 NMR 光谱，pH 范围 2.0 < pH < 2.5，37°C。结果发现，在所有研究的 Ac-L-Met-Gly 二肽反应中，Met-Gly 酰胺键均发生断裂，但配合物2a和3a 的催化活性低于1a 。然而，在与 Ac-L-His-Gly 二肽的反应中，仅在配合物1a中观察到涉及组氨酸羧基的酰胺键的水解。所观察到的这些配合物催化活性的差异被认为是由于桥接 qx、qz 和 phtz 配体中氮原子的相对位置不同以及随之而来的两个铂 (II) 金属中心的分子内分离的变化。