Synthesis, structure and characterization of two new metal–organic coordination polymers based on the ligand 5-iodobenzene-1,3-dicarboxylate

Abstract

Two new coordination polymers (CPs) formed from 5-iodobenzene-1,3-dicarboxylic acid (H2iip) in the presence of the flexible 1,4-bis(1H-imidazol-1-yl)butane (bimb) auxiliary ligand, namely poly[[μ2-1,4-bis(1H-imidazol-1-yl)butane-κ2N3:N3′](μ3-5-iodobenzene-1,3-dicarboxylato-κ4O1,O1′:O3:O3′)cobalt(II)], [Co(C8H3IO4)(C10H14N4)]nor [Co(iip)(bimb)]n, (1), and poly[[[μ2-1,4-bis(1H-imidazol-1-yl)butane-κ2N3:N3′](μ2-5-iodobenzene-1,3-dicarboxylato-κ2O1:O3)zinc(II)] trihydrate], {[Zn(C8H3IO4)(C10H14N4)]·3H2O}nor {[Zn(iip)(bimb)]·3H2O}n, (2), were synthesized and characterized by FT–IR spectroscopy, thermogravimetric analysis (TGA), solid-state UV–Vis spectroscopy, single-crystal X-ray diffraction analysis and powder X-ray diffraction analysis (PXRD). The iip2−ligand in (1) adopts the (κ1,κ1-μ2)(κ1, κ1-μ1)-μ3coordination mode, linking adjacent secondary building units into a ladder-like chain. These chains are further connected by the flexible bimb ligand in atrans–trans–transconformation. As a result, a twofold three-dimensional interpenetrating α-Po network is formed. Complex (2) exhibits a two-dimensional (4,4) topological network architecture in which the iip2−ligand shows the (κ1)(κ1)-μ2coordination mode. The solid-state UV–Vis spectra of (1) and (2) were investigated, together with the fluorescence properties of (2) in the solid state.