A novel nickel metal–organic framework with fluorite-like structure: gas adsorption properties and catalytic activity in Knoevenagel condensation?

Dalton Transactions Pub Date: 2013-12-18 DOI: 10.1039/C3DT52698D

Abstract

A new non-interpenetrating 3D metal–organic framework {[Ni4(μ6-MTB)2(μ2-H2O)4(H2O)4]·10DMF·11H2O}n (DMF = N,N′-dimethylformamide) built from nickel(II) ions as connectors and methanetetrabenzoate ligands (MTB4?) as linkers has been synthesized and characterized. The single crystal X-ray diffraction showed that complex exhibits CaF2-like fluorite structure topology and four types of 3D channels with sizes about 12.6 × 9.4 ?2, 9.4 × 8.0 ?2, 12.6 × 11.7 ?2 and 14.9 × 14.9 ?2, which are filled with guest molecules. Conditions of the activation of the compound have been studied and optimized by powder X-ray diffraction during in situ heating, thermogravimetric analysis and infrared spectroscopy. Nitrogen and carbon dioxide adsorption showed that the activated sample exhibits a BET specific surface area of 700 m2 g?1 and a carbon dioxide uptake of 12.36 wt% at 0 °C, which are the highest values reported for the compounds of the MTB4? series. The complex was tested in Knoevenagel condensation of aldehydes and active methylene compounds. Straightforward dependence of the substrate conversion on the size of used aldehyde was established. A possible mechanism of Knoevenagel condensation over a MTB4? containing a metal–organic framework was proposed.

Graphical abstract: A novel nickel metal–organic framework with fluorite-like structure: gas adsorption properties and catalytic activity in Knoevenagel condensation
Recommended Literature