Synthesis and stability of bis(acetato)(5,10,15,20-tetraphenylporphyrinato)zirconium(IV)

The results of studying a unique synthesis method, the kinetics and mechanism of dissociation in acid media, and the stability of a new octacoordinated zirconium complex with two bidentate acetate ligands and one 5,10,15,20-tetraphenylporphine ligand, (AcO)(2)ZrTPP, are presented. The method of synthesis is distinguished by the use of stable ZrOCl(2) in the complex formation reaction, instead of readily hydrolyzed zirconium tetrachloride, in boiling phenol, which exhibits the reduction properties. The UV, visible, IR, and (1)H NMR spectral parameters and the values of chromatographic mobility and stability of the complex are obtained. A protolytic dissociation scheme, which is universal for mixed porphyrin-containing zirconium complexes, is substantiated using data on the dissociation rates of an (Cl)(2)ZrTPP analogue, depending on the temperature and acidity of the medium. The scheme includes a trimolecular rate-determining step (the complex ionized at one or both noncyclic ligands and two nonionized sulfuric acid molecules) and kinetically significant equilibria of dissociation of the noncyclic acido ligands and sulfuric acid.