Zinc complexes of a new N₃O ligand and their biomimetic reactions

详细信息    查看全文

• 作者：J.A. Maldonado Calvo and H. Vahrenkamp
• 关键词：Zinc complexes ; Nitrogen ligands ; Hydroxide complexes ; Biomimetic reactions
• 刊名：Inorganica Chimica Acta
• 出版年：2005
• 出版时间：1 September 2005
• 年：2005
• 卷：358
• 期：13
• 页码：4019-4026
• 全文大小：321 K

文摘

The new N₃O ligand 2-(pyridylmethylamino)-3-(3,5-dimethylpyrazol-1-yl)-propionic acid (L1H) was synthesized and converted to L1Zn–Cl and L1Zn–Br. These complexes are tetrameric in the solid state with bridging carboxylate functions. The reaction of deprotonated L1H with zinc nitrate or zinc perchlorate yielded the aqua complexes [L1Zn–OH₂] X with and , which crystallize as carboxylate-bridged dimers. Their deprotonation produced, in situ, the hydroxide complex L1Zn–OH, which acted as a base toward p-nitrophenol and bis(p-nitrophenyl)phosphoric acid resulting in L1Zn–ONit and L1Zn-OPO(ONit)₂. Tris(p-nitrophenyl)phosphate was cleaved hydrolytically by L1Zn–OH, releasing one p-nitrophenyl group. A kinetic investigation of this cleavage reaction under pseudo-first-order conditions has yielded second-order rate constants k″ of 0.9 s⁻¹ M⁻¹ in 50 % aqueous DMSO and 4.0 s⁻¹ M⁻¹ in 75 % aqueous DMSO.