Sitting-atop complex formation of free base meso-tetraarylporphyrins with zirconium(IV) chloride

We have succeeded in the preparation and spectroscopic characterization of sitting-atop (SAT) complexes of meso-tetraarylporphyrins (H2t(X)pp) with zirconium(IV) chloride under mild conditions and at room temperature, where two pyrrolenine nitrogens in the SAT complexes, [(H2t(X)pp)ZrCl4], coordinate to a zirconium atom and two protons still remain on the pyrrole nitrogens. UV–Vis and NMR (1H and 13C) spectral data show that the porphyrin core of the SAT complexes is distorted and two pyrrolenine nitrogen atoms of the porphyrin act as electron donors to the zirconium atom of ZrCl4.

Graphical abstractThe reaction of meso-tetraarylporphyrin (H2t(X)pp) and ZrCl4 leads to the formation of the SAT complex, [(H2t(X)pp)ZrCl4], in which two pyrrolenine nitrogen atoms of the porphyrin act as electron donors to a zirconium atom, and two protons still remain on the pyrrole nitrogens.Figure optionsDownload full-size imageDownload as PowerPoint slide