Coordination Reaction between Series Hydroxyl-Porphyrins and Pb<sup>2+</sup> Studied by Spectroscopic Method

Reaction conditions and spectroscopy properties of series hydroxyl-porphyrins for bonding with Pb 2+ were described. A stable complex was formed with molar ratio 1:1 in the solution of N,N-dimethylformamide (DMF) with 0.6ml tween-80 as surfactant, when the pH was controlled at 6.5. The hydroxyl group on the benzene ring resulted in Soret band red shift of Pb-porphyrin complexes from 415.8 to 422.7nm, and isosbestic point of the axial coordination reaction appeared at 419.5nm. The study of thermodynamics predicted that the monohydroxyl-porphyrin had the optimal identification effects for Pb 2+ .