title: Effective cleavage of phosphodiester promoted by the zinc(II) and copper(II) inclusion complexes of β-cyclodextrin.
abstract: To construct the model of metallohydrolase, two inclusion complexes [MLCl2(β-CD)] (1, M=Zn(II); 2, M=Cu(II); L=N,N'-bis(2-pyridylmethyl)amantadine; β-CD=β-cyclodextrin) were synthesized by mixing β-CDs with the pre-synthesized complexes G1, [ZnLCl2] and G2, [CuLCl2]. Structures of G1, G2, 1 and 2 were characterized by X-ray crystallography, respectively. In solution, two chloride anions of G1 and G2 underwent ligand exchange with solvent molecules according to ESI-MS analysis. The chemical equilibrium constants were determined by potentiometric pH titration. The kinetics of bis(4-nitrophenyl) phosphate (BNPP) hydrolysis catalyzed by G1, G2, 1 and 2 were examined at pHs ranging from 7.50 to 10.50 at 308±0.1K. The pH profile of rate constant of BNPP hydrolysis catalyzed by 1 exhibited an exponential increase with the second-order rate constant of 2.68×10-3M-1s-1assigned to the di-hydroxo species, which was approximately an order of magnitude higher than those of reported mono-Zn(II)-hydroxo species. The high reactivity was presumably hydroxyl-rich microenvironment provided by β-CDs, which might effect in stabilizing either the labile zinc-hydroxo species or the catalytic transition state.
authors: College of Chemistry and Materials Science, Center for Nano Science and Technology, The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Normal University, Wuhu 241000, China. Electronic address: yhzhou@mail.ahnu.edu.cn.
authors: Ying-Hua
authors: YH
authors: Zhou
authors: College of Chemistry and Materials Science, Center for Nano Science and Technology, The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Normal University, Wuhu 241000, China.
authors: Li-Qing
authors: LQ
authors: Chen
authors: College of Chemistry and Materials Science, Center for Nano Science and Technology, The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Normal University, Wuhu 241000, China.
authors: Jun
authors: J
authors: Tao
authors: College of Chemistry and Materials Science, Center for Nano Science and Technology, The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Normal University, Wuhu 241000, China.
authors: Jun-Li
authors: JL
authors: Shen
authors: College of Chemistry and Materials Science, Center for Nano Science and Technology, The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Normal University, Wuhu 241000, China.
authors: Dao-Yu
authors: DY
authors: Gong
authors: College of Chemistry and Materials Science, Center for Nano Science and Technology, The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Normal University, Wuhu 241000, China.
authors: Rui-Rui
authors: RR
authors: Yun
authors: College of Chemistry and Materials Science, Center for Nano Science and Technology, The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Normal University, Wuhu 241000, China.
authors: Yong
authors: Y
authors: Cheng
mesh_terms: D003300:Copper / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008956:Models, Chemical; D009596:Nitrophenols / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D009596:Nitrophenols; D047392:beta-Cyclodextrins; C002887:bis(4-nitrophenyl)phosphate; D003300:Copper; D015032:Zinc; C031215:betadex
keywords: BNPP hydrolysis; Copper(II) complex; Cyclodextrin; Mimic; Supramolecule; Zinc(II) complex