1,3-Propanediammonium [μ4-1,2,4,5-benzenetetracarboxylato(4-) ]copper(II) dihydrate with a microporous structure

Abstract

Crystal structure analysis of the title complex, (H3NC 3H6NH3)[Cu{C6H2(COO) 4}] ·2H2O, showed that the structure is built up from Cu(II) and tetradentate 1,2,4,5-benzenetetracarboxylate(4-) (btc) ions forming a 3D open-framework with two different channels extending parallel to the [110]/[1,-1,0] and [001] directions. The first, wider channels accommodate 1,3-propanediammonium cations, whereas the second ones are filled with H 2O molecules. The Cu(II) ions are in a tetrahedrally distorted square-planar environment consisting of four carboxylate O atoms from four different btc ligands. The four uncoordinated O atoms from the same carboxylate groups are placed around Cu(II) at longer distances (≈ 2.8 A), forming a distorted sphenoid. The complex crystallizes in the orthorhombic space group Cc2m with a = 8.887(1), b = 11.493(2), c = 16.457(3) Å, K= 1680.9(5) Å3 and Z=4. Final agreement indices are: R, = 0.0303 for 1012 reflections with 1 > 2σ(I), wR2 = 0.0493 for 1317 independent reflections and 123 refined parameters. The compound was also characterized by IR spectroscopy and TG/DSC analysis.