Diez-Castellnou Marta, Salassa Giovanni, Mancin Fabrizio, Scrimin Paolo
EaStCHEM School of Chemistry, University of St Andrews, St. Andrews, United Kingdom.
Département de Chimie Physique, Université de Genève, Genève, Switzerland.
Front Chem. 2019 Jul 3;7:469. doi: 10.3389/fchem.2019.00469. eCollection 2019.
In this paper, the unusual reactivity of the complex Zn(II)-1,4,7-trimethyl-1, 4,7-triazacyclononane () in the transesterification of the RNA-model substrate, (), is reported. The dependence of the reactivity (k) with pH does not follow the characteristic bell-shape profile typical of complexes with penta-coordinated metal centers. By the contrary, two reactive species, featuring different deprotonation states, are present, with the tri-aqua complex being more reactive than the mono-hydroxy-diaqua one. Apparently, such a difference arises from the total complex charge which plays an important role in the stability of the transition state/s of the reactions. Relevant insight on the reaction mechanism were hence obtained.
本文报道了配合物Zn(II)-1,4,7-三甲基-1,4,7-三氮杂环壬烷（）在RNA模型底物（）的酯交换反应中的异常反应活性。反应活性（k）与pH的关系并不遵循具有五配位金属中心的配合物典型的特征钟形曲线。相反，存在两种具有不同去质子化状态的反应性物种，三水配合物比单羟基二水配合物更具反应活性。显然，这种差异源于总配合物电荷，其在反应过渡态的稳定性中起重要作用。因此获得了关于反应机理的相关见解。
