A new open-framework manganese-gallium phosphate has been synthesized under solvothermal conditions and characterized by single-crystal XRD, thermogravimetric analysis, and magnetic susceptibility measurements [crystal data: [MnGa(PO3OH)2(PO4)][C6N 2H14], Mr = 525.76, monoclinic, space group P21/n (No. 14), a = 10.193(1), b = 14.276(1), and c = 10.380 (1) Å, ß = 91.184(8)°, V = 1510 Å3, Z = 4, R = 5.8%, Rw = 7.8% (2331 observed data with I > 3s(I))]. The structure consists of MnO5, GaO4, and PO4 units linked to form a three-dimensional microporous framework encapsulating 1,4-diazabicyclo[2.2.2]octane cations. The Mn2+ ions have distorted square-pyramidal geometry and exist in Mn2(HPO4)4 units within the framework. Antiferromagnetic ordering at TN = 10(1) K is ascribed to coupling between Mn2+ ions in these subunits, and the temperature dependence of the susceptibility can be successfully fitted assuming a Heisenberg exchange interaction (J = -2.07(1) cm-1, g = 2.25(1)). At higher temperatures (>70 K) Curie-Weiss paramagnetism is observed (? = -20.2(2) K, µeff = 6.69(1)µB).
|Number of pages||6|
|Journal||Chemistry of Materials|
|Publication status||Published - Dec 1997|