Preparation, Crystal Structure, Thermal Decomposition Mechanism And Kinetics Of Complexes Dysprosium Aromatic Carboxylic Acid With 1,10-Phenanthroline

Seventeen ternary complexes of Dy(â…¢) have been synthesized in this paper, in which aromatic acid were as the first ligand, and 1,10-phenanthroline as the second ligand. Their element analysis and titration of EDTA indicate the complexes have the composition of [Dy(BA)₃phen]₂,[Dy(o-MBA)₃phen]₂,[Dy(m-MBA)₃phen]₂?H2O,[Dy(p-MBA)₃phen]₂,[Dy(o-MOBA)₃phen]₂·1.5H2O,[Dy(m-MOBA)₃phen]₂,[Dy(p-MOBA)₃phen]₂,[Dy(o-NBA)₃phen]₂,[Dy(m-NBA)₃phen]₂·4H2O,[Dy(p-NBA)₃phen]₂·3H2O,[Dy(o-ClBA)₃phen]₂,[Dy(m-ClBA)₃phen]₂,[Dy(p-ClBA)₃phen]₂·2H2O,[Dy(2,4-DClBA)₃phen]₂?H2O,[Dy(p-FBA)₃phen]₂,[Dy(o-FBA)₃phen]₂,[Dy(p-ABA)3phen·H2O]·1.5 H2O. Their IR spectra,UV,molar conductivities,thermal analysis and XRD were be studied.The structure of five ternary complexes of [Dy(BA)₃phen]₂,[Dy(m-MBA)₃phen]₂?H2O,[Dy(p-MOBA)₃phen]₂,[Dy(p-FBA)₃phen]₂,[Dy(p-ABA)3phen·H2O]·1.5 H2O have been determined using X-ray diffraction. Coordinate mode of carboxylate groups and dysprosium ion are bidentate bridging,tridentate chelating-bridging and bidentate chelating。The crystal structures of [Dy(BA)₃phen]₂ and [Dy(p-FBA)₃phen]₂ exist as binuclear molecular, and crystallize in triclinic, space group P-1, eight coordinate. [Dy(m-MBA)₃phen]₂·H2O exists as binuclear molecular, and crystallize in monoclinic, space group Cc, eight coordinate. [Dy(p-MOBA)₃phen]₂ exists as binuclear molecular, and crystallize in monoclinic, space group P2(1)/n, nine coordinate. [Dy(p-ABA)3phen·H2O]·1.5 H2O exists as mononuclear molecular, and crystallize in triclinic, space group P1, nine coordinate.Thermal analysis was further carried to determine the decomposition temperature of complexes using both TG-DTG and DSC techniques. The non-isothermal kinetic parameters were obtained by using differential isoconversional non-linear method(NL-DIF),integral non-linear procedure(NL-INT) and Popescu method. The kinetic equation of the first decomposition of [Dy(p-MBA)₃phen]₂ can be expressed as:In addition, the lifetime equation at weight-loss of 10% was deduced aslnÏ„= -19.6528+15424.1613/TThe same method is to [Dy(p-MOBA)₃phen]₂ and[Dy(p-FBA)₃phen]₂ to determine their lifetime equations. Their lifetime equations are as follows:lnÏ„=–28.8361+19478.37/TlnÏ„=–27.0798+19010.2434/TThe most probable mechanism functions, activation energy E and pre-exponential factor A of dehydration process for complexes [Dy(p-ClBA)₃phen]₂·2H2O,[Dy(p-NBA)₃phen]₂·3H2O and [Dy(m-NBA)₃phen]₂·4H2O were obtained based on DSC curves, and the kinetic equations are as follows:The thermodynamic parameters (ΔG≠,ΔH≠和ΔS≠) of dehydration process for complex [Dy(p-ClBA)₃phen]₂·2H2O were calculated.