Synthesis and spectroscopic characterization of the new sitting-atop complexes from reaction of zirconyl nitrate and free base meso-Tetraarylporphyrins in mild conditions

Abstract

A series of sitting-atop (SAT) complexes, [(ZrO)H2t(X)pp(NO3)2], have been prepared via the reactions of free base meso-tetraarylporphyrins, H2t(X)pp, with zirconyl nitrate hydrate, ZrO(NO3)2·xH2O. The products have been characterized by a variety of methods including 1H NMR, 13C NMR, IR and UV-Vis spectroscopies, elemental analysis and conductance measurements. The data indicate that the meso-tetraarylporphyrins coordinate with two pyrrolenine nitrogen atoms to the zirconyl cation located above the distorted porphyrin plane and two protons remain on the pyrrole nitrogens. Such half sandwich-type sitting-atop complexes may be considered as models for the initial steps of the metallation of the macrocycles.