Abstract

Pd(AEMP)Cl₂ (AEMP = 2-(2-aminoethyl)-1-methylpyrrolidine) was synthesized and characterized by spectral and thermal measurements.[Pd(AEMP)(H₂O)₂]²⁺ reacts with amino acid esters (L) to form mixed ligand [Pd(AEMP)L]²⁺ complexes. The kinetics of the base hydrolysis of [Pd(AEMP)L]²⁺ was studied by a pH-stat technique and the corresponding rate constants are reported. The coordinated glycine methyl ester is hydrolyzed efficiently, whereas the coordinated methionine- and histidine- methyl esters undergo hydrolysis with a much lower catalytic activity. The catalytic effect is controlled by the mode of coordination of the ester to the Pd(II) complex. Possible mechanisms for these reactions are considered. Activation parameters were determined experimentally for the hydrolysis of the coordinated glycine methyl ester. DFT calculations (B3LYP/def2svp) were applied to gain further insight into the possible mechanism of the base hydrolysis of the amino acid esters. The calculations are discussed in reference to the reported experimental data.

Graphic abstract

中文翻译：

---

[Pd（AEMP）（H 2 O）2] 2+（AEMP = 2-（2-氨基乙基）-1-甲基吡咯烷）催化α-氨基酸酯碱水解的动力学，机理和密度泛函理论计算

摘要

合成了Pd（AEMP）Cl ₂（AEMP = 2-（2-氨基乙基）-1-甲基吡咯烷），并通过光谱和热分析对其进行了表征。[Pd（AEMP）（H ₂ O）₂ ] ²⁺与氨基酸酯反应（L）形成混合的配体[Pd （ AEMP ） L] ²⁺复合物。[Pd（AEMP）L] ^2+的碱水解动力学通过pH-stat技术进行了研究，并报道了相应的速率常数。配位的甘氨酸甲酯被有效地水解，而配位的甲硫氨酸和组氨酸甲酯被水解而具有较低的催化活性。催化作用由酯与Pd（II）配合物的配位方式控制。考虑了这些反应的可能机制。通过实验确定了配位甘氨酸甲酯水解的活化参数。使用DFT计算（B3LYP / def2svp）可以进一步了解氨基酸酯碱基水解的可能机理。参考报告的实验数据讨论了计算。

图形摘要