Three-dimensional cobalt(II) and cadmium(II) MOFs containing 1,4-naphthalenedicarboxylate: Catalytic activity of Cd-MOF

Abstract

Three-dimensional (3D) cobalt(II) and cadmium(II) metal-organic frameworks (MOFs) bearing rigid 1,4-naphthalenedicarboxylate (1,4-NDC) linkers were prepared and their solid-state structures were characterized by X-ray crystallography. Both Co-MOF and Cd-MOF exhibited isostructural frameworks. 1,4-NDC ligands bridge the metal ions in chelating/bridging and simple bridging modes to form a 1D chains, and these 1D chains are interconnected by 1,4-NDC to form 3D frameworks with the formula of [M-2(1,4-NDC)(2)(DMF)(2)] (M = Co-II or Cd-II). The as-prepared Cd-MOF was found to be catalytically active for the cyanosilylation reaction of aromatic aldehydes with nitro substituent in varying positions in the presence of trimethylsilyl cyanide to afford cyanohydrin trimethylsilyl ethers in a shape and size selective manner. The catalytic reaction is thought to have mainly occurred inside the Cd-MOF micropores which were generated through the partial dissociation of DMF ligands near the surfaces of Cd-MOF, where openly accessible coordination sites are available once the labile DMF ligands dissociate from Cd-II ions. The as-prepared Co-MOF did not exhibit catalytic activities for the same reaction. (C) 2015 Elsevier Ltd. All rights reserved.