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

Abstract

Two novel coordination polymers, {[Cu₂(THFTCA)(phen)] · H₂O}_n (1) and [Cd₂(THFTCA)(H₂O)₃]_n (2) (H₄THFTCA = (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 P2₁/c space group. The structure of complex 1 is based on 2D (3,6)-connected kgd-type (4³)₂(4⁶.6⁶.8³) layers, which are further extended into a 3D supramolecular architecture through π–π 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 (4⁴.6²)(4⁶.6⁹) 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.