High-dimensional malonate-based materials: Synthesis, crystal structures and magnetic properties of [M2(mal)2(L)(H2O)2]n·n(H2O) M = Zn(ii), Co(ii); H2mal = malonic acid, L = pyrimidine, pyrazine

Abstract

Four novel coordination polymers [M₂(mal)₂(pym)(H₂O)]_n·nH₂O, M = Zn (1), Co (2) and [M₂(mal)₂(pyz)(H₂O)]_n·nH₂O, M = Zn (3), Co (4) (H₂mal = malonic acid, pym = pyrimidine, pyz = pyrazine), have been synthesized. Compounds 1 and 2 are isomorphous, as are compounds 3 and 4. X-ray diffraction experiments reveal that 1–4 exhibit an interesting 3D-network, containing malonate and either pyrimidine (1 and 2) and pyrazine (3 and 4) as organic ligands. Variable-temperature magnetic susceptibility measurements indicate the occurrence of weak antiferromagnetic interactions between Co(II) ions in 2 and 4.