Design of a Dinuclear
Nickel(II) Bioinspired Hydrolase
to Bind Covalently to Silica Surfaces: Synthesis, Magnetism, and Reactivity
Studies
- Publication date
- Publisher
Abstract
Presented herein is the design of a dinuclear Ni<sup>II</sup> synthetic
hydrolase [Ni<sub>2</sub>(HBPPAMFF)(μ-OAc)<sub>2</sub>(H<sub>2</sub>O)]BPh<sub>4</sub> (<b>1</b>) (H<sub>2</sub>BPPAMFF
= 2-[(<i>N</i>-benzyl-<i>N</i>-2-pyridylmethylamine)]-4-methyl-6-[<i>N</i>-(2-pyridylmethyl)aminomethyl)])-4-methyl-6-formylphenol)
to be covalently attached to silica surfaces, while maintaining its
catalytic activity. An aldehyde-containing ligand (H<sub>2</sub>BPPAMFF)
provides a reactive functional group that can serve as a cross-linking
group to bind the complex to an organoalkoxysilane and later to the
silica surfaces or directly to amino-modified surfaces. The dinuclear
Ni<sup>II</sup> complex covalently attached to the silica surfaces
was fully characterized by different techniques. The catalytic turnover
number (<i>k</i><sub>cat</sub>) of the immobilized Ni<sup>II</sup>Ni<sup>II</sup> catalyst in the hydrolysis of 2,4-bis(dinitrophenyl)phosphate
is comparable to the homogeneous reaction; however, the catalyst interaction
with the support enhanced the substrate to complex association constant,
and consequently, the catalytic efficiency (<i>E</i> = <i>k</i><sub>cat</sub>/<i>K</i><sub>M</sub>) and the
supported catalyst can be reused for subsequent diester hydrolysis
reactions