The Electronic Absorption Characteristics of Mixed Phthalocyaninato Porphyrinato Rare Earth(III) Triple-Deckers M2(TPyP)2(Pc)

Mixed phthalocyaninato tetrakis(4-pyridyl)porphyrinato rare earth triple-decker complexes M2(TPyP)2(Pc) [M = La (1), Eu (2)] have been prepared by condensation between M(TPyP)acac generated in situ and M(Pc)2. Their symmetrical structure (TPyP)M(Pc)M(TPyP) was verified by 1H NMR (1D and 2D) spectra in CDCl3 solutions. The electronic absorption spectra of these two compounds were recorded in the UV/Vis and near-IR region. A weak absorption in the near-IR region at 860 and 942 nm for 1 and 2, respectively, was observed as the lowest energy band and is attributed to the electronic transition from HOMO to LUMO for these mono(phthalocyaninato) bis(porphyrinato) rare earth complexes. Their electrochemical properties were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Analysis of the relationship between the optical and redox properties of M2(TPyP)2(Pc) reveals that the HOMO and LUMO of M2(TPyP)2(Pc) have both porphyrin and phthalocyanine character.