Hydrothermal synthesis, crystal structure and magnetic properties of a copper(II) phosphonate

The treatment of 3-ammonium-1-hydroxypropylidene-1,1'-bisphosphonate (H7ahdp) and 4,4'-bipy with CuCl2 center dot 2H(2)O resulted in a metal phosphonate [Cu(H(5)ahdp)center dot H2O](n). Its crystal structure has been characterized by single X-ray crystallography. Although there is no 4,4'-bipy in the lattice structure, it plays a very important role in forming the one-dimensional chain of the polymer. Hydrogen bonds link the chains into a 3D network. The dinuclear secondary building units are observed in the compound. The determination of variable-temperature magnetic susceptibilities (5 similar to 300 K) shows weak intrachain antiferromagnetic coupling between copper(II) centers. The magnetic data were fitted to the appropriate equations derived from the Hamiltonian H = -2JS(1)S(2), giving the parameter J = -25.78 cm(-1). Its thermal properties were also investigated.