New La(III) complex immobilized on 3‑aminopropyl-functionalized silica as an efficient and reusable catalyst for hydrolysis of phosphate ester bonds

摘要

Described herein is the synthesis, structure, and monoesterase and diesterase activities of a new mononuclear [LaIII(L1)(NO3)2] (1) complex (H2L1 = 2-bis[{(2-pyridylmethyl)- aminomethyl}-6-[N-(2-pyridylmethyl) aminomethyl)])- 4-methyl-6-formylphenol) in the hydrolysis of 2,4- bis(dinitrophenyl)phosphate (2,4-BDNPP). When covalently linked to 3-aminopropyl-functionalized silica, 1 undergoes disproportionation to form a dinuclear species (APS-1), whose catalytic efficiency is increased when compared to the homogeneous reaction due to second coordination sphere effects which increase the substrate to complex association constant. The anchored catalyst APS-1 can be recovered and reused for subsequent hydrolysis reactions (five times) with only a slight loss in activity. In the presence of DNA, we suggest that 1 is also converted into the dinuclear active species as observed with APS-1, and both were shown to be efficient in DNA cleavage.