Synthesis and Characterization of Rare Earth Corrole-Phthalocyanine Heteroleptic Triple-Decker Complexes

We recently reported the first example of a europium triple-decker tetrapyrrole with mixed corrole and phthalocyanine macrocycles and have now extended the synthetic method to prepare a series of rare earth corrolephthalocyanine heteroleptic triple-decker complexes, which are characterized by spectroscopic and electrochemical methods. The examined complexes are represented as M-2[Pc(OC4H9)(8)](2)[Cor(ClPh)(3)], where Pc = phthalocyanine, Cor = corrole, and M is Pr(III), Nd(III), Sm(III), Eu(110, Gd(III), or Tb(III). The Y(III) derivative with OC4H9 Pc substituents was obtained in too low a yield to characterize, but for the purpose of comparison, Y-2[Pc(OC5H11)(8)](2)[Cor(ClPh)(3)] was synthesized and characterized in a similar manner. The molecular structure of Eu-2[Pc(OC4H9)(8)](2)[Cor(ClPh)(3)] was determined by single-crystal X-ray diffraction and showed the corrole to be the central macrocycle of the triple-decker unit with a phthalocyanine on each end. Each triple-decker complex undergoes up to eight reversible or quasireversible one-electron oxidations and reductions with E-1/2 values being linearly related to the ionic radius of the central ions. The energy (E) of the main Qband is also linearly related to the radius of the metal. Comparisons are made between the physicochemical properties of the newly synthesized mixed corrole-phthalocyanine complexes and previously characterized double- and triple-decker derivatives with phthalocyanine and/or porphyrin macrocycles.