Coordination polymers of transition metal diphosphonates: Synthesis, crystal structure and magnetic behaviour

Five new transition metal coordination polymers: [Cu2L(4,4'-bipy)(H2O)(0.5)] (1), [Cu(H2L)H2O] (2), [Cd-2(H2L)(2)H2O] (3), [Co2L(H2O)(2)center dot 0.184H(2)O (4), [Fe3L2(OH)(H2O)(3) ]center dot 2H(2)O (5) (H4L = 4-CH3-C6H4CH2N (CH2PO3H2)(2)), were obtained through hydrothermal reactions. The complexes have been characterized by IR, elemental analysis, TGA and XRD. Crystal structure analysis reveals that all of 2-5 contain 2D inorganic layer structures, constructed by the coordination interactions between metal ions and phosphonate oxygen atoms. 4,4'-bipy molecules in 1 act as a bridging ligand to connect the adjacent 2D layers into a 3D framework. Moreover, magnetic properties of the complexes have been quantificationally investigated by the classical spin approximation and PHI software program, revealing that 2, 4 and 5 exhibit antiferromagnetism, while 1 shows ferromagnetism. (C) 2018 Elsevier Ltd. All rights reserved.