The thermal decomposition of Tb_2(O-MBA)_6(PHEN)_2 (O-MBA: o-methylbenzoate;PHEN: 1,10-phenanthroline) and its kinetics were studied under the non-isothermal condition bythermogravimetry-derivative thermogravimetry (T...The thermal decomposition of Tb_2(O-MBA)_6(PHEN)_2 (O-MBA: o-methylbenzoate;PHEN: 1,10-phenanthroline) and its kinetics were studied under the non-isothermal condition bythermogravimetry-derivative thermogravimetry (TG-DTG) techniques. Kinetic parameters were obtainedfrom analysis of TG-DTG curves by the Achar method and the Madhusudanan-Krishnan-Ninan (MKN) method.The most probable mechanism function was suggested by comparing the kinetic parameters. The kineticequation for the first stage can be expressed as dα/dt = Aexp(-E/RT)·3(1 - α)^(2/3). Thelifetime equation at mass loss of 10% was deduced as lnτ= -28.7429 + 19797.795/T by isothermalthermogravimetric analysis.展开更多
A terbium o-methylbenzoate complex with 1,10-phenanthroline, Tb(o-MBA)_3phen(where o-MBA = o-methylbenzoate and phen = 1,10-phenanthroline) was prepared from ethanol solutionand its crystal structure was determined by...A terbium o-methylbenzoate complex with 1,10-phenanthroline, Tb(o-MBA)_3phen(where o-MBA = o-methylbenzoate and phen = 1,10-phenanthroline) was prepared from ethanol solutionand its crystal structure was determined by X-ray diffraction. The crystal of the complexTb(o-MBA)_3phen belongs to triclinic crystal system and P1 (#2) space group. The crystal data are asfollows: a = 1.4371(4) nm, b = 1.7387(2) nm, c = 1.3109(2) nm, α = 96.37(1)°, β = 107.21(2)°,γ= 82.78(2)°, Ⅴ= 3.094(1) nm^3, Z= 2, M_r = 1489.12, D_c= 1.598 g·cm^(-3), μ = 2.330 mm^(-1)and F(000) = 1488.00. The final R and R_w are 0.038 and 0.047 for 8668 [Ⅰ > 2σ(Ⅰ)] uniquereflections, respectively. In the complex each Tb^(3+) ion is eight-coordinated by one1,10-phenanthroline molecule, one bidentate carboxylate group and four bridging carboxylate groups.The carboxylate groups are bonded to the terbium ion in two modes: the chelating bidentate and thebridging bidentate. Excitation and luminescence data observed at room temperature show that thetitle complex emits strong green fluorescence under ultraviolet light. The results of thermalanalysis indicate that the complex Tb(o-MBA)_3phen is quite stable to heat.展开更多
The thermal behavior of Tb_2(BA)_6(PHEN)_2 (BA: benzoate, and PHEN:1,10-phenanthroline) in a static air atmosphere was investigated by TG-DTG, SEM and IR techniques.By the kinetic method of processing thermal analysis...The thermal behavior of Tb_2(BA)_6(PHEN)_2 (BA: benzoate, and PHEN:1,10-phenanthroline) in a static air atmosphere was investigated by TG-DTG, SEM and IR techniques.By the kinetic method of processing thermal analysis data put forward by Malek et al., it is definedthat the kinetic model for the first-step thermal decomposition is SB(m, n). The activation energyE for this step reaction is 99.07 kJ/mol, the entropy of activation ΔS~≠ is -84.72 J/mol, theenthalpy of activation ΔH~≠ is 94.26 kJ/mol, the free energy of activation ΔG~≠ is 144.77 kJ/moland the pre-exponential factor lnA is 20.93. The lifetime equation at mass-loss of 10% was deducedas lnτ = -29.0312 + 19760.83/T by isothermal thermogravimetric analysis.展开更多
Silica gel luminophors containing 1, 10-phenanthroline-tris(M-Methylbenzoate) europium (or terbium) com- plexes were prepared bysol-gel method. The thermal decomposition, excitation and emissionspectra for the gel pho...Silica gel luminophors containing 1, 10-phenanthroline-tris(M-Methylbenzoate) europium (or terbium) com- plexes were prepared bysol-gel method. The thermal decomposition, excitation and emissionspectra for the gel phos- phors were measured and compared with thatof solid complex powders. The thermal stability of the complexes wasen- hanced in SiO_2 host matrix and the luminescence intensityremained unchanged.展开更多
基金This project was financially supported by the Natural Science Foundation of Hebei Province (Nos. 202140 and 203148) Hebei Education Department (No. 2001121)
文摘The thermal decomposition of Tb_2(O-MBA)_6(PHEN)_2 (O-MBA: o-methylbenzoate;PHEN: 1,10-phenanthroline) and its kinetics were studied under the non-isothermal condition bythermogravimetry-derivative thermogravimetry (TG-DTG) techniques. Kinetic parameters were obtainedfrom analysis of TG-DTG curves by the Achar method and the Madhusudanan-Krishnan-Ninan (MKN) method.The most probable mechanism function was suggested by comparing the kinetic parameters. The kineticequation for the first stage can be expressed as dα/dt = Aexp(-E/RT)·3(1 - α)^(2/3). Thelifetime equation at mass loss of 10% was deduced as lnτ= -28.7429 + 19797.795/T by isothermalthermogravimetric analysis.
基金The project is financially supported by the Natural Science Foundation of Hebei Province (No. 202140 and No. 203148)
文摘A terbium o-methylbenzoate complex with 1,10-phenanthroline, Tb(o-MBA)_3phen(where o-MBA = o-methylbenzoate and phen = 1,10-phenanthroline) was prepared from ethanol solutionand its crystal structure was determined by X-ray diffraction. The crystal of the complexTb(o-MBA)_3phen belongs to triclinic crystal system and P1 (#2) space group. The crystal data are asfollows: a = 1.4371(4) nm, b = 1.7387(2) nm, c = 1.3109(2) nm, α = 96.37(1)°, β = 107.21(2)°,γ= 82.78(2)°, Ⅴ= 3.094(1) nm^3, Z= 2, M_r = 1489.12, D_c= 1.598 g·cm^(-3), μ = 2.330 mm^(-1)and F(000) = 1488.00. The final R and R_w are 0.038 and 0.047 for 8668 [Ⅰ > 2σ(Ⅰ)] uniquereflections, respectively. In the complex each Tb^(3+) ion is eight-coordinated by one1,10-phenanthroline molecule, one bidentate carboxylate group and four bridging carboxylate groups.The carboxylate groups are bonded to the terbium ion in two modes: the chelating bidentate and thebridging bidentate. Excitation and luminescence data observed at room temperature show that thetitle complex emits strong green fluorescence under ultraviolet light. The results of thermalanalysis indicate that the complex Tb(o-MBA)_3phen is quite stable to heat.
基金This project was supported by the Natural Science Foundation of Hebei Province (No. 202140 No. 203148) and Hebei Education Department (No. 2001121).
文摘The thermal behavior of Tb_2(BA)_6(PHEN)_2 (BA: benzoate, and PHEN:1,10-phenanthroline) in a static air atmosphere was investigated by TG-DTG, SEM and IR techniques.By the kinetic method of processing thermal analysis data put forward by Malek et al., it is definedthat the kinetic model for the first-step thermal decomposition is SB(m, n). The activation energyE for this step reaction is 99.07 kJ/mol, the entropy of activation ΔS~≠ is -84.72 J/mol, theenthalpy of activation ΔH~≠ is 94.26 kJ/mol, the free energy of activation ΔG~≠ is 144.77 kJ/moland the pre-exponential factor lnA is 20.93. The lifetime equation at mass-loss of 10% was deducedas lnτ = -29.0312 + 19760.83/T by isothermal thermogravimetric analysis.
基金This project is financially supported by Natural Science Foundation of Hebei Province, China (No. 299193)
文摘Silica gel luminophors containing 1, 10-phenanthroline-tris(M-Methylbenzoate) europium (or terbium) com- plexes were prepared bysol-gel method. The thermal decomposition, excitation and emissionspectra for the gel phos- phors were measured and compared with thatof solid complex powders. The thermal stability of the complexes wasen- hanced in SiO_2 host matrix and the luminescence intensityremained unchanged.
