Preparations, structures and properties of heterobimetallic complexes based on tetrahydrofuran-2,3,4,5-tetracarboxylate

Transition heterobimetallic metal-organic frameworks based on tetrahydrofuran-2,3,4,5-tetracarboxylicate (FTA), namely [M(H2O)6][Cu2M(FTA)2(H2O)2]·4H2O [M=Mn (1), Co (2)], and [CuZn(FTA)(H2O)5]·H2O (3) have been synthesized and characterized. Single-crystal X-ray diffraction indicates that complexes 1 and 2 are isomorphic. In 1 and 2, FTA ligand links the metal ions to a 2-D wave-like negative-charged layer with a topology of {4;62}2{4;63;82}2{6}. They possess 1-D channels with [M(H2O)6]2+ and lattice water molecules enclathrated. While in the complex 3, Cu2+ and Zn2+ ions are bridged by FTA to a 2-D neutral layer structure with a {8}2{84;122} topology. Magnetic properties of 1–3 were analyzed in connection with their structures, which show that there exist weak antiferromagnetic interactions between metal ions.

Three heterobimetallic MOFs were constructed through the size-selectivity of TFA coordination sites for different transition metal ions based on the concept of “Hard and Soft Acids and Bases”.Figure optionsDownload as PowerPoint slideHighlights
► Complexes 1 and 3 contain 2-D wave-like negative-charged layers.
► Complex 2 is a 2-D neutral layer structure with a {8}2{84;122} topology.
► Complexes 1–3 are the first example of heterobimetallic MOFs based on FTA.
► The coordination sites of FTA show size-selectivity to metal ions.