catena-Poly[[[tetraaquacadmium(II)]-μ-3,3′-[p-phenylenebis(oxymethylene)]bis(1-pyridinioacetate)] dinitrate hemihydrate]

Abstract

In the title polymeric coordination complex, {[Cd(C22H20N2O6)(H2O)4](NO3)2·0.5H2O}n, obtained from the self-assembly of the flexible double betaine 3,3′-[p-phenyl­enebis(oxymethyl­ene)]bis­(1-pyridinioacetate) with cadmium nitrate, both the octa­hedrally coordinated CdII cation and the substituted betaine ligand lie on inversion centres. The chains constructed through the trans-related acetate groups of the ligand are inter-connected via O—H⋯O hydrogen bonds involving coordinated aqua ligands, the nitrate anions and the partial-occupancy (0.25) water mol­ecule of solvation, forming a three-dimensional structure.