Novel (3,6)-connected network and (4,6)-connected framework in two copper(II) and cadmium(II) complexes of flexible (2S,3S,4R,5R)-tetrahydrofurantetracarboxylic acid: synthesis, structure, thermostability, and luminescence studies

Two novel coordination polymers, {[Cu-2(THFTCA)(phen)] center dot H2O}(n) (1) and [Cd-2(THFTCA)(H2O)(3)](n) (2) (H(4)THFTCA = (2S,3S,4R,5R)-tetrahydrofurantetracarboxylic acid, phen = 1,10-phenanthroline), have been prepared under hydro(solvo) thermal conditions and characterized by X-ray diffraction, infrared spectroscopy, elemental analysis and thermogravimetric analysis. Single-crystal X-ray diffraction analysis reveals that both complexes 1 and 2 crystallize in the P2(1)/c space group. The structure of complex 1 is based on 2D (3,6)-connected kgd-type (4(3))(2)(4(6).6(6).8(3)) layers, which are further extended into a 3D supramolecular architecture through pi-pi packing interactions of phen. Complex 2 is the first reported Cd-tetrahydrofurantetracarboxylate and represents a complicated 3D metal organic framework (MOF) structure with (4,6)-connected (4(4).6(2))(4(6).6(9)) topology. The configurations of THFTCA ligands in the two complexes are all meso-(2S,3S,4R,5R) form. The luminescent properties of 2 have also been investigated.