Abstract: Twonewoxovanadiumcomplexes withpoly(pyrazolyl)borate and carboxylic acid as ligands,VO[phCH2CH(NH2)COO][HB(pz)3] (1) and VO(3,5-Me2pz)[HB(3,5-Me2pz)3](CH3COO) (2), were synthesized successfully. The two complexes were characterized by IR, elemental analyses, thermal analyses, and single crystal X-ray diffraction. The study of non-isothermal decomposition kinetics for complex 1 showed that the possible reaction mechanisms of the two steps were nucleation and growth with n=1/4, and chemical reaction, respectively; the kinetic equations may be expressed as dα/dT=(A/β)e-E/RT(1/4)(1-α)[-ln(1-α)]-3 and dα/dT=(A/β)e-E/RT(1-α)2, respectively, the apparent activation energies of the steps are 223.52 and 331.94 kJ·mol-1, respectively, the pre-exponentials ln(A/s-1) are 49.67 as well as 57.50. The study of non-isothermal decomposition kinetics for complex 2 showed: the possible reaction mechanisms of the two steps were chemical reaction, and nucleation and growth with n=1/2, respectively, the kinetic equations may be expressed as dα/dT=(A/β)e-E/RT(1-α)2, and dα/dT=(A/β)e-E/RT(1/2)(1-α)[-ln(1-α)]-1, respectively, the apparent activation energies of the steps were 300.56 and 444.72 kJ·mol-1, respectively, the pre-exponentials ln(A/s-1) were 75.53 as well
as 92.50.

Key words: Vanadiumcomplex, Poly(pyrazolyl)borate, Crystal structure, Thermal decomposition kinetics