New one-, two-, and three-dimensional metal-organic frameworks based on magnesium(II): synthesis and structure

Six new metal-organic frameworks based on magnesium(II) ions of various dimensionality were synthesized: chain-like [Mg(Hazdc)2(nmp)2] (1, H2azdc is 4,4′-azobenzenedicarboxylic acid, nmp is N-methylpyrrolidone), layered [Mg(H2btc)(nmp)2] (2, H4btc is 1,2,4,5-benzene-tetracarboxylic acid), [Mg3(sdc)3(def)4] •3DEF (3, H2sdc is 4,4’-stilbenedicarboxylic acid, def or DEF is N,N-diethylformamide), [Mg3(azdc)3(dma)4] • 3DMA (4, dma or DMA is N,N-di-methylacetamide), [Mg3(azdc)3(dmf)4] (5, dmf is N,N-dimethylformamide), and doubly-interpenetrated three-dimensional [Mg3(azdc)3(nmp)4] •NMP (6, NMP is N-methylpyrrolidone). According to the single-crystal X-ray dif raction data, compounds 1 and 2 are built from mononuclear carboxylate units {Mg(RCOOH)2(RCOO)2(nmp)2}. Compounds 3-6 are composed on trinuclear carboxylate units {Mg3(RCOO)6}. In isostructural compounds 3-5, these units are linked to each other through carboxylate bridges to form polymer layers; in compound 6, these units are linked together to form a doubly-interpenetrated three-dimensional metal-organic framework.