A new material [Ni2 (BODC)2 (TED)], (BODC=4, 4′ -bicyclo[2.2.2]octane dicarboxylate and TED=triethylene-4, 4′ -diamine), which is a guest-free, porous metal-organic coordination network, has been successfully synthesized. The crystal structure of this compound is tetragonal with the space group P4mmm. It is a three-dimensional network that can be deconstructed into rectangular gridlike layers along ab planes. These planes are formed by BODC and Zn2 O4 paddle-wheel-like clusters, and the TED ligands from the axial directions of the paddle-wheels connect the layers into a three-dimesional structure. There are no guest molecules found in the pores. The shortest Ni-Ni distance within the paddle wheel is found to be 2.613 Å. Magnetic susceptibility (T) =M (T) H and isothermal magnetization M (H) measurements have been measured on powder samples of this compound. The results of (T) show that there is a rapid increase in the susceptibility below 20 K due to a spontaneous ordering of the Ni2+ moments. The effective moment μeff of Ni2+ is about 2.20 μB at room temperature. The M (H) result at 1.8 K shows a clear hysteresis with a coercivity of Hcoe ≈1700 G. The behavior of this compound is discussed in terms of Ni-Ni coupling within the Ni dimers and dimer chains.
ASJC Scopus subject areas
- Physics and Astronomy(all)