Sandwich intermediate sitting-atop complexation between free base meso-tetraarylporphyrins and tellurium(IV) chloride

Abstract

Free base meso-tetraarylporphyrins (H2T(X)PP) react with tellurium(IV) chloride (TeCl4) in mild conditions for formation sandwich intermediate sitting-atop (i-SAT) complexes, [TeCl4(H 2T(X)PP)2]. 1H NMR, 13C NMR, UV-vis, FT-IR and elemental analysis were used for characterization of the products. In the proposed structure of the i-SAT complexes, four pyrroles of each porphyrin ring are tilted alternatively up and down and this appropriates suitable orientation of lone pairs of two pyrrolenine nitrogens for electron donation to a tellurium center. 1H NMR and FT-IR results showed that in the produced complex, hydrogen atoms of porphyrin macrocycles remained on the pyrrole nitrogens.