Trinuclear Metal Complexes Based on 1,10-Phenanthroline Derivates as Catalysts for Cleavage of a RNA-Model Substrate

摘要

Two multidentate ligands 2,9-di [6'-(2"-hydroxyl -3"-methoxyphenyl) -n-2',5'-diazahexyl ] -1,10-phenanthroline (LA) and 2,9 -di ( 6'-α-phenol-n-2', 5' -diazahexyl) - 1,10 - phenanthroline ( LB ) were synthesized and fully characterized. Protonation of the ligands and the stability of the complexes of the ligands with divalent metal ions were investigated. The trinuclear metal complexes [ Cu (Ⅱ) and Zn (Ⅱ)] of the ligands were studied, as catalysts, for the transphosphorylation of the RNA-model substrate 2-hydroxypropyl-p-nitrophenyl phosphate(HPNP). The second-order rate constants of HPNP-hydrolysis catalyzed by M3L and M3LH-1 were obtained, which indicated that Zn3LBH-1 was the most efficient catalyst among them. The proposed mechanisms included the activation of the substrate via binding to the metal ions and intramolecular nucleophilic attack by the deprotonated C2-hydroxyl of HPNP.