Synthesis and Characterization of Mixed Phthalocyaninato and meso-Tetrakis(4-chlorophenyl)porphyrinato Triple-Decker Complexes − Revealing the Origin of Their Electronic Absorptions

Two series of mixed phthalocyaninato and porphyrinato rare earth(III) triple‐decker complexes [M2(Pc)(TClPP)2] (1a−10a) and [M2(Pc)2(TClPP)] (1b−11b) [M = Y, La−Er except Ce and Pm; Pc = phthalocyaninate; TClPP = tetrakis(4‐chlorophenyl)porphyrinate] have been prepared by treating the half‐sandwich complexes [M(TClPP)(acac)] (acac = acetylacetonate), generated in situ from [M(acac)3]·nH2O and H2(TClPP), with Li2(Pc). All the triple‐decker complexes have been characterized by a wide range of spectroscopic and electrochemical methods. The molecular structures of [M2(Pc)(TClPP)2] (M = Y, Ho) have also been determined, and show a symmetrical disposition of ligands, with two outer domed TClPP and one inner Pc rings. A systematic investigation of the optical and electrochemical data of these complexes has revealed the nature of the HOMO and LUMO, as well as the origin of the electronic absorptions of these triple‐decker complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)