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, {[Ho2(HCAM)6Mn3(H2O)12]·17.5H2O}n (1), {[Er2(HCAM)6Mn3(H2O)12]·17.5H2O}n (2), {[Ho2(HCAM)6Zn3(H2O)12]·26H2O}n (3), and {[Er2(HCAM)6Zn3(H2O)12]·26H2O}n (4) (H3CAM = chelidamic acid). X-ray crystallographic studies reveal that coordination polymers 1−4 are isostructural and crystallized in the rhombohedral crystal system, space group R3̅. 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 Ho3+/Er3+ and Mn2+ ions within 1 and 2.