Structures and magnetic properties of ferromagnetic coupling 2D Ln-M heterometallic coordination polymers (Ln = Ho, Er; M = Mn, Zn)

Four new heterometallic coordination polymers have been successfully synthesized, namely, {Ho(2)(HCAM)(6)Mn(3)(H(2)O)(12)].17.5H(2)O}(n) (1), {Er(2)(HCAM)(6)Mn(3)(H(2)O)(12)].17.5H(2)O}(n) (2), {Ho(2)(HCAM)(6)Zn(3)(H(2)O)(12)].26H(2)O}(n) (3), and {Er(2)(HCAM)(6)Zn(3)(H(2)O)(12)].26H(2)O}(n) (4) (H(3)CAM = chelidamic acid). X-ray crystallographic studies reveal that coordination polymers 1-4 are isostructural and crystallized in the rhombohedral crystal system, space group R3. These compounds comprise a 2D honeycomb-type framework. A 2D water sheet is first found in 3 and 4, which exhibits a novel topological motif. The magnetic results for 1-4 show that ferromagnetic interactions take place between the Ho(3+)/Er(3+) and Mn(2+) ions within 1 and 2.