Two new self-penetrating metal-organic frameworks based on a flexible cyclohexanetetracarboxylate ligand

Two new metal-organic frameworks, [M2(CTA)(bipy)1.5(H2O)2]n·3n(H2O) (M = Cd for 1 and Mn for 2, H4CTA = cyclohexane-1,2,4,5-tetracarboxylic acid, bipy = 4,4′-bipyridine) have been successfully synthesized and characterized. Complexes 1 and 2 are isostructural, which display unusual three-dimensional (3D) self-penetrating coordination frameworks with 3-nodal (3,5,5)-connectivity and the Schläfli symbol of (4,6,8)(42,67,8)(43,63,83,9). Moreover, in solid state, complex 1 exhibits blue emission at ambient temperature. Magnetic measurement shows that there exist weak antiferromagnetic interactions in 2.