catena-Poly[[[tetraaquaerbium(III)]-μ-oxalato-κ4O1,O2:O1′,O2′] [bromidobis(pyrazine-2-carboxylato-κ2N1,O)cuprate(II)] tetrahydrate]

Abstract

In the title heterometallic complex, {[Er(C2O4)(H2O)4][CuBr(C5H3N2O2)2]·4H2O}n, the ErIII atom is eight-coordinated by four O atoms from two centrosymmetric oxalate ligands and four water molecules, displaying a bicapped trigonal-prismatic geometry. The oxalate ligands bridge the Er atoms into a polymeric cationic chain along [110]. The CuII atom is five-coordinated in a square-pyramidal geometry by two pyrazine-2-carboxylate ligands and a Br atom, forming a discrete anion. The polymeric cations, complex anions and uncoordinated water molecules are self-assembled into a three-dimensional supramolecular network through O—H...N, O—H...O and O—H...Br hydrogen bonds.