The bi rare earth complexes EuTb( m MBA) 6(phen) 2·2H 2O, TbY( m MBA) 6(phen) 2·2H 2O were synthesized by the reaction of RECl 3 with m methylbenzoic acid and 1,10 phenanthroline in ethanol solution, where m MBA=m methylbenzoate and phen=1,10 phenanthroline. The luminescence properties of the title complexes were studied in comparison with the corresponding complexes Eu 2( m MBA) 6(phen) 2·2H 2O and Tb 2( m MBA) 6(phen) 2·2H 2O respectively. The results indicate that the emission intensity from europium ion can be greatly enhanced by the terbium ion, while the emission from terbium ion was strongly quenched by europium ion in EuTb( m MBA) 6(phen) 2·2H 2O; the emission intensity from terbium ion can be greatly enhanced by yttrium ion in TbY( m MBA) 6(phen) 2·2H 2O. The mechanism about the results was discussed.
The thermal decomposition of the magnesium oxalate dihydrate in a static air atmosphere was investigated by TG-DTG techniques. The intermediate and residue of each decomposition were identified from their TG curve. The kinetic triplet, the activation energy E, the pre-exponential factor A and the mechanism functionsf（a） were obtained from analysis of the TG-DTG curves of thermal decomposition of the first stage and the second stage by the Popesou method and the Flynn-Wall-Ozawa method.
A terbium benzoate complex with 1,10-phenanthroline [Tb(ba)3(phen)]2, where ba = benzoate and phen = 1,10-phenanthroline, has been prepared and structurally characterized by X-ray diffraction. It crystallizes in triclinic, space group P1 with a = 10.7881(5), b = 11.9262(6), c = 12.4249(6) ?, a = 105.1260(10), β = 93.6010(10), ? = 113.3350(10)o, (C33H23N2O6Tb)2, Mr = 1404.90, V = 1391.87(12) ?3, Z = 1, Dc = 1.676 g/cm3, μ(MoKα) = 2.590 mm-1, F(000) = 696, the final R = 0.0277 and wR = 0.0670 for 6085 observed reflections with I > 2σ(I). The crystal consists of binuclear molecules of the title compound. Each Tb3+ ion is nine-coordinated to one 1,10-phenan- throline molecule, one bidentate carboxylate group and four bridging carboxylate groups. The carboxylate groups are bonded to the terbium ion in three modes: the chelating bidentate, bridging bidentate and bridging-chelating tridentates. Excitation and luminescence data observed at room temperature show that the title complex emits very intensive green fluorescence under ultraviolet light. The results of thermal analysis indicate that the complex [Tb(ba)3phen]2 is very thermal stable.
The title complex [Sm(o-MOBA)3(phen)·H2O]2·4H2O has been synthesized by the reaction of SmCl3·6H2O with o-methoxybenzoic acid and 1,10-phenanthroline in 1∶3∶1 molar ratio. The crystal structure was determined by X-ray single crystal diffraction. The crystal belongs to triclinic system, space group P1 with a=1.203(10) nm, b=1.293(10) nm, c=1.306(11) nm, α=64.50(10)°, β=81.93(10)°, γ=74.81(10)°. The molecular structure shows that the Sm3+ ion coordinates to nine atoms. The carboxylate groups are bonded to the samarium ion in three modes: monodentate, bidentate chelating, tridentate chelating-bridging. CCDC: 603740.
The complex [Sm（p-MBA）3phen]2 （p-MBA, p-methylbenzoate; phen, 1,10-phenanthroline） was prepared and characterized by elemental analysis, IR and UV spectra. The thermal decomposition process of [Sm（pMBA）3phen]2 was studied under a static air atmosphere by TG-DTG and IR techniques. Thermal decomposition kinetics was investigated employing a newly proposed method, together with the integral isoconversional non-finear method. Meanwhile, the thermodynamic parameters （AH#, △G# and AS#） were also calculated. The lifetime equation at mass-loss of 10% was deduced as In r=-24.7825＋ 18070.43/T by isothermal thermogravimetric analysis.
