Kinetic Study on p-Nitrophenyl Picolinate Hydrolysis Catalyzed by Metallomicelle
β Scribed by Min WANG; Jun LI; Xuemei SANG; Jiaqing XIE
- Book ID
- 104452729
- Publisher
- Elsevier Science
- Year
- 2007
- Weight
- 428 KB
- Volume
- 28
- Category
- Article
- ISSN
- 1872-2067
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β¦ Synopsis
Two transition metal ion macrocyclic complexes, NiR and CuR (R: 5,7,7,12,14,4,8,11-tetraazacyclotetradecane perchloric acid), were synthesized and characterized. Metallomicelles made up of nickel (II) and copper (II) complexes with surfactant n-lauroyl sarcosinate were used as a mimetic hydrolytic metalloenzyme for catalytic hydrolysis of p-nitrophenyl picolinate (PNPP). The specific absorption spectra of the hydrolytic reaction systems indicated that the key intermediates made up of PNPP and Ni(II) or Cu(II) complex were formed during the reaction process. Based on the specific absorption spectra, the mechanism of PNPP catalytic hydrolysis was proposed, and a kinetic mathematical model was established. The results showed that the two metallomicelles exhibit high catalytic activity for the hydrolysis of PNPP. The catalytic hydrolysis of PNPP is an intramolecular nucleophilic substitution reaction, so the rate of the catalytic reaction is higher than that of spontaneous hydrolysis. The catalytic mechanism proposed is supported by the results of spectral analysis and the kinetic calculation. The structure of NiR and CuR is similar so that the difference in the catalytic activity between the two metallomicelles is less.
π SIMILAR VOLUMES
## Abstract Two Schiff base cobalt(II) complexes containing crowned substituents have been synthesized and employed to promote the hydrolysis of __p__βnitrophenyl picolinate (PNPP) in a buffered micellar solution formed by a cationic Gemini surfactant, bis(hexadecyldimethylammonium)hexane bromide (