抗癌性钌配合物HLtrans-RuⅢCl4L2(L=4H-1,2,4-triazole)水解机理的理论研究

摘要

采用密度泛函理论(DFT)方法,并结合导体极化连续模型(CPCM)研究了具有抗肿瘤活性的“Keppler型”钌配合物[Htrz]trans-RuⅢCl4(4H-1,2,4-triazole)2](1)的水解反应过程.首先,在B1B95/(LanL2DZ+6-31G(d))理论水平上对水解反应中各平衡构型在气相条件下的有关结构进行全几何优化及振动频率分析.然后,在更高的基组水平LanL2DZ(f)+6-311 ++G(3df,2dp)上对优化的结构进行单点能计算,并考虑溶剂效应.计算得到水解反应过程中相应的结构特征和详细的反应势能面.对于第一步水解,水溶液中配合物1的活化能垒为116.6 kJ·mol-1,比已经报道的配合物[ImH][trans-RuⅢCl4(Im)2](ICR)的活化能垒高得多,进一步证实了降低含氮杂环中N原子碱性,可增强配合物在水溶液中的稳定性的水解规律.对于第二步水解,如同已经研究的多数“Keppler型”抗肿瘤钌配合物一样,反应在热力学上优先生成顺式双水解产物.%The hydrolysis process of an antitumor Ru(Ⅲ) complex [Htrz][trans-RuⅢCl4(4H-l,2,4-triazole)2] (1), has been investigated by using density functional theory (DFT) method combing with the conductor-like polarizable calculation model (CPCM). First, the full geometry optimizations and frequency calculations in vacuo for each related counterpoise geometry were carried out at the theoretical level of BlB95/(LanL2DZ+6-31G(d)). Then, single-point energies were further calculated in gas phase and in solution at LanL2DZ(f)+6-311++G(3df,2dp) level on optimized structures. The structural characteristics and the detailed energy profiles for the hydrolysis processes of this complex were obtained. For the first hydrolysis step, complex 1 has the activation energy of 116.6 kJ·mol-1 in aqueous solution, which is more higher than that of reported antitumor complex [ImH] [trans-RuⅢCl4(Im)2](ICR), again proved that the decrease in basicity of the nitrogen heterocyclic ligand results in kinetic stabilization of the Ru(Ⅲ) complex. For the second hydrolysis step, like more studied "Keppler type" antitumor　Ru(Ⅲ) complexes, it is very significant to find that the formation of cis-diaqua products is thermodynamicly preferred to that of trans isomers.