The layered structure of poly[[hexaaqua(μ4-benzene-1,2,4,5- tetracarboxylato) dicopper(II)] tetrahydrate]

Abstract

In the structure of the title compound, {[Cu-2(C10H2O8)-(H2O)(6)]center dot 4H(2)O}(n), the benzene-1,2,4,5-tetracarboxylate ligand, (btec)(4-), is located on a crystallographic inversion centre in a 4-coordination mode. The coordination environment of each pentacoordinated Cu-II centre is square pyramidal (SBP), formed by three water molecules and two carboxylate O atoms from two different (btec)(4-) ligands. The completely deprotonated (btec)(4-) ligand coordinates in a monodentate mode to four Cu-II atoms. The alternation of (btec)(4-) ligands and SBP Cu-II centres leads to the formation of a planar two-dimensional covalent network of parallelograms, parallel to the ab plane. Hydrogen bonds between a basal water molecule and an apical one from an adjacent [Cu(btec)(0.5)(H2O)(3)] unit exist in the intralayer space. Hydrogen bonds are also present between the two-dimensional network and the water molecules filling the channels in the structure.