Syntheses, Structures And Studies On Thermal Decomposition Of Series Of Lanthanide Complexes With Heterocyclic As Ligands

Four Lanthanides complexes and three transition metal complex with N-phenyl ligands were synthesized under the room temperature and hydrothermal condition. The complexes have been characterized by elemental analysis, IR and the crystal structures were determined by X-ray diffraction. Further more, the thermal decomposition processes of the complexes were discussed detailed, and the kinetics of thermal decomposition of the 5 complexes were studied by thermal analysis technique under non-isothermal condition. The formulas of these seven complexes are as follows:(1) [Sm2(phen)₂ (CH₃COO)₄(NO₃)₂](2) [Nd2(phen)₂(CH₃COO)₄(NO₃)₂](3) [Eu(phen)₂(NO₃)₃](4) [Ho(phen)₂(NO₃)₃](5) [V₆O₁₂(phen)₄(CH₃O)₄]·4H₂O(6) [Cu(H₂B(pz)₂)₂](7) [Ni(H₂B(pz)₂)₂]Non-isothermal thermal decomposition kinetic studies revealed that, both of the possible reaction mechanisms of the 1st step thermal decomposition of complex 1 and complex 3 were fit with the 6th function, the kinetic equation may be expressed as dα/dT = 4A/βe^-E/RT(1-α)^1/2[1- (1-α)^1/2]^1/2, and the apparent activation energy of each reaction were 145.06, 196.70kJ/mol, and pre-exponential factor were lnA = 26.95, 34.31, respectively. And both of the possible reaction mechanism of the 1st step thermal decomposition of complex 2 and the 2nd step of complex 4 were fit with the 23rd function, the kinetic equation may be expressed as dα/dT = (A/β)e^-E/RT, and the apparent activation energy of each reaction were 271.72, 256.81kJ/mol, and pre-exponential factor were lnA = 52.00, 45.58, respectively. The possible reaction mechanisms of 1st and 2nd step thermal decomposition of complex 7 were fit with the 3rd and 17th function, respectively. And each kinetic equation may be expressed as dα/dT = 3(A/β)e^-E/RT[(1-α)^-1/3-1]¹/2 and dα/dT = 2(A/β)e^-E/RT(1-α)^1/2, respectively. Each apparent activation energy were 260.87, 176.27kJ/mol, and pre-exponential factor were lnA = 65.65, 37.11, respectively.