Construction of mixed corrole–phthalocyanine europium triple-decker complexes involving meso-substituted trans-A2B-corrole

Abstract

With the view to exploit novel rare-earth heteroleptic corrole–phthalocyanine triple-decker complexes towards their potential applications in the fields of information storage devices and nonlinear optical materials, three europium triple-decker complexes containing one meso-substituted trans-A₂B-corrole and two phthalocyanine macrocycles have been designed and synthesized. The investigated compounds are represented as Eu₂[Pc(OC₄H₉)₈]₂[Cor(p-R¹Ph)₂(p-R²Ph)], where Pc = phthalocyanine, Cor = corrole, (p-R¹Ph) and (p-R²Ph) are the substituents on the 5,15-meso and 10-meso positions of the corrole macrocycle, respectively, R¹ is H, and R² is a CH₃O, F or Cl substituent at the para-position of the meso-phenyl ring. These novel europium triple-decker complexes were characterized by spectroscopic and electrochemical techniques in nonaqueous media. Under excitation at 633 nm, a typical Raman marker band of the phthalocyanine dianions Pc²⁻ is observed at 1505 cm⁻¹, resulting from the coupling of the CC (pyrrole) and CN (aza group) stretchings. The UV-visible spectra and redox potentials of each triple-decker were analyzed as a function of the sum of the Hammett substituent constants for the para-substituents on the meso-phenyl rings of the corrole macrocycle.