A coordination polymer [Co(dpa)prz0.5]n(1) with double-helix chains has been constructed hydrothermally using H2dpa(H2dpa=diphenic acid),prz(prz=piperazine) and Co(NO3)2.6H2O.The structure and magnetic properties of the complex were investigated.The complex crystallizes in triclinic system and P1 space group.Each Co atom is five-coordinated and takes a distorted tetragonal pyramid geometry.Two carboxylates of the H2dpa ligands bridge four Co(Ⅱ) ions to form infinite right-handed or left-handed helical-C-O-Co-chains.The two types of helical chains are interconnected to each other through the Co (Ⅱ) centers to produce double-helix chains.The chains form a 2D sheet through the coordination interaction of prz molecules between adjacent chains.The sheets are further interlinked by hydrogen bond interactions to generate 3D coordination frameworks.Magnetic studies for complex 1 show stronger antiferromagnetic coupling between the Co(Ⅱ) ions.
