title: A novel nickel metal-organic framework with fluorite-like structure: gas adsorption properties and catalytic activity in Knoevenagel condensation.
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 (MTB(4-)) 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 Å(2), 9.4 × 8.0 Å(2), 12.6 × 11.7 Å(2) and 14.9 × 14.9 Å(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 m(2) 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 MTB(4-) 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 MTB(4-) containing a metal-organic framework was proposed.
authors.affiliation: Department of Inorganic Chemistry, Faculty of Science, P. J. Šafárik University, Moyzesova 11, 041 54 Košice, Slovak Republic. vladimir.zelenak@upjs.sk.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Almáši
authors.forename: Vladimír
authors.initials: V
authors.lastname: Zeleňák
authors.forename: Maksym
authors.initials: M
authors.lastname: Opanasenko
authors.forename: Jíří
authors.initials: J
authors.lastname: Cejka