Preparation, structural characterization, and thermal behaviors of Nd(III) compounds derived from 3,5-dinitropyridone.

Three neodymium compounds, Nd(4DNP)3(C2H5OH)3 (1), Nd(4DNPO)3 · 7H2O (2), and {[Nd(μ-ox)(4DNPO)(H2O)4] · 4H2O}n (3) (4HDNP, 3,5-dinitropyrid-4-one; 4HDNPO, 3,5-dinitropyrid-4-one-N-hydroxide; ox, oxalate), were synthesized and characterized by FT-IR, elemental analysis, thermogravimetry-differential scanning calorimetry (TG-DSC), and two of them by single-crystal X-ray diffraction analyses. The results revealed that in 1, the Nd(III) is surrounded by three chelating ligands and three ethanol solvent molecules. The structure of 3 could be described as 1-D chains in which Nd is bis-bidentately bridged by oxalates, together with a monodentate 3,5-dinitropyrid-4-onate N-oxide 4DNPO ligand and four water molecules as well as four uncoordinated water molecules in the crystal lattice. The origin of the oxalate anions in 3 is probably due to decomposition of the 4DNPO or its oxidation of other species. The TG-DTG (DTG, derivative thermogravimetry) and DSC analyses showed that 1 underwent a three-stage decomposition process. A kinetic equation for decomposition reaction of 2 was also obtained. The apparent activation energy (Ea) and pre-exponential factor (A) of the main decomposition reaction are 157.70 kJ mol-1 and 1011.97 s-1, respectively. The kinetic equation can thus be expressed as dα/dt = 1011.97(1 - α)e-1.90 × 104/T. [ABSTRACT FROM AUTHOR]