Two polymorphic forms of a mixed zinc/copper biquinoline dihydrogenphosphate

Abstract

Two polymorphic forms of a mixed zinc/copper biquinoline dihydrogenphosphate are presented, showing almost identical monomeric units, viz. (2,2 '-biquinoline-kappa N-2,N ')bis(dihydrogenphosphato-kappa O)copper(II)/zinc(II), formulated as [ZnxCu1-x(H2PO4)(2)(C18H12N2)], with x = 0.88 (1) and 0.90 (2). The cation is tetrahedrally coordinated to a chelating biquinoline system and two diprotonated phosphate anions. The structures differ mainly in their intermolecular hydrogen-bonding interactions, leading to different packing schemes. No significant evidence of stress due to the Zn/Cu solid solution formation was detected.