Beer’s law experiment, variable-temperature spectral experiment of UV-Vis absorption,H NMR, and measurement of magnetic moment were conducted for NiTMPyP in aqueous solution. It was found that Beer’s law was obeyed in concentration range 8 x 10-7-2 x 10-5.mol’dm-3.With the temperature increasing from 0 ℃ to 95 ℃, the isosbestic point appeared at 435 nmand the lowest downfield H NMR peak narrowed gradually and shifted to upfield. The magneticmoment is 2.07 BM in D2O at 30 ℃, but in the D2O-CD3COCD3 mised solvent there was noevidence for the existance of paramagnetic species. These results show that NiTMPyP exists inaqueous solution as an equilibrium mixture of diamagnetic, four-coordinate nickel (Ⅱ) and paramagnetic, sir-coordinate nickel (Ⅱ) complexed by water molecules in the axial position. Thethermodynamic parameters of the edal-coordinated reaction
