Study on kinetics and mechanism of dinuclear metal zinc(II) complexes in promoting the hydrolysis of 2-hydroxy-propyl- p-nitrophenyl phosphate (HPNP)

• Published in: Journal of molecular catalysis. A, Chemical Chemical, 2008-10, Vol.293 (1), p.79-85
• Main Authors: Wu, XiangXia, Lin, Hai, Shao, Jie, Lin, Huakuan
• Format: Article
• Language: English
• Subjects: 1,10-Phenanthroline; 2-Hydroxy-propyl- p-nitrophenyl phosphate (HPNP); Catalysis; Chemistry; Exact sciences and technology; General and physical chemistry; Hydrolysis; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Zinc(II)
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/j.molcata.2008.07.008

Five multi-dentate ligands: N,N′-di-(1,10-phenanthroline-2-methylene)-ethylenediamine (L1), N,N′-di-(1,10-phenanthroline-2-methylene)-1,3-propanediamine (L2), 1,7-di- (1,10-phenanthroline-2-methylene)-1,4,7-triazaheptane (L3), 1,10-di-(1,10-phenanthroline-2-methylene)-1,4,7,10-tetraazatridecane (L4), 1,13-di-(1,10-phenanthroline-2-methylene)-1,4,7,10,13-pentaazatridecane (L5) have been synthesized and characterized. The hydrolytic kinetics catalyzed by dinuclear complexes of Zn(II) with L1–L5 have been studied in aqueous solution at 298.2 ± 0.1 K, I = 0.10 mol dm −3 KNO 3 at physiological condition (pH 7.0–8.4), respectively. In this study it is found that the catalytic effect of Zn 2L3 was the best one among the five dinuclear complexes for the hydrolysis of 2-hydroxy-propyl- p-nitrophenyl phosphate (HPNP). Its k Z n 2 L 2 H − 1 , k Z n 2 L 2 and p K a are 0.0480 mol −1 dm 3 s −1, 0.000043 mol −1 dm 3 s −1 and 8.87, respectively. This paper expounds the result from the structure of the ligands and the properties of the metal ions, and deduces the catalysis mechanism. Five multi-dentate ligands have been synthesized and characterized. The hydrolytic kinetics catalyzed by dinuclear complexes of Zn(II) with L1–L5 have been studied in aqueous solution at 298.2 ± 0.1 K, I = 0.10 mol dm −3 KNO 3 at pH 7.0–8.5, respectively. The results showed that the catalytic effect of Zn 2L3 was the best in the five dinuclear complexes for hydrolysis of 2-hydroxy-propyl- p-nitrophenyl phosphate (HPNP). ▪