A three‐dimensional ZnII coordination network based on 5,5′‐methylenebis(2,4,6‐trimethylisophthalic acid) and 2,7‐bis(1H‐imidazol‐1‐yl)fluorene: synthesis, structure and luminescence properties

In recent years, coordination polymers constructed from multidentate carboxyl­ate ligands and N-containing ligands have attracted much attention since these ligands can adopt a rich variety of coordination modes which can lead to crystal­line products with intriguing structures and inter­esting properties. A new coordination polymer, namely poly[[di­aqua­[μ-2,7-bis­(1H-imidazol-1-yl)fluor­ene-κ2N3:N3′][μ-5,5′-methyl­enebis(3-carb­oxy-2,4,6-tri­methyl­benzoato)-κ2O1:O1′]zinc(II)] hemihydrate], {[Zn(C23H22O8)(C19H14N4)(H2O)2]·0.5H2O}n, 1, was pre­pared by the self-assembly of Zn(NO3)2·6H2O with 5,5′-methyl­enebis(2,4,6-tri­methyl­isophthalic acid) (H4BTMIPA) and 2,7-bis­(1H-imidazol-1-yl)fluorene (BIF) under solvothermal conditions. The structure of 1 was determined by elemental analysis, single-crystal X-ray crystallography, powder X-ray diffraction, IR spectroscopy and thermogravimetric analysis. Each ZnII ion is six-coordinated by two O atoms from two H2BTMIPA2− ligands, by two N atoms from two BIF ligands and by two water mol­ecules, forming a distorted octa­hedral ZnN2O4 coordination geometry. Adjacent ZnII ions are linked by H2BTMIPA2− ligands and BIF ligands, leading to the formation of a two-dimensional (2D) (4,4)-sql network, and inter­molecular hydrogen-bonding inter­actions connect the 2D layer structure into the three-dimensional (3D) supra­molecular structure. Each 2D layer contains two kinds of helices with the same direction, which are opposite in adjacent layers. The luminescence properties of complex 1 in the solid state have also been investigated.