Controlling the nature of mixed (phthalocyaninato)(porphyrinato) rare-earth(III) double-decker complexes : The effects of nonperipheral alkoxy substitution of the phthalocyanine ligand

The half-sandwich rare-earth complexes [M^III(acac)(TClPP)] (M = Sm, Eu, Y; TClPP = meso-tetrakis (4-chlorophenyl)porphyrinate; acac = acetylacetonate), generated in situ from [M(acac)₃]·n H ₂O and H₂(TClPP), were treated with 1,8,15,22-tetrakis(3- pentyloxy)phthalocyanine [H₂{Pc(α-OC₅H ₁₁)₄]} (Pc = phthalocyaninate) under reflux in n-octanol to yield both the neutral nonprotonated and protonated (phthalocyaninato) (porphyrinato) rare-earth double-decker complexes, [M^III{Pc(α- OC₅H₁₁)₄}(TClPP)] (1-3) and [M ^IIIH{Pc(α-OC₅H₁₁)₄}(TClPP)] (4-6), respectively. In contrast, reaction of [Y^III(acac)(TClPP)] with 1,4,8,11,15,18,22,25-octakis(1-butyloxy)-phthalocyanine [H ₂Pc(α-OC₄H₉)₈] gave only the protonated double-decker complex [Y^IIIH{Pc(α-OC ₄H₉)₈}-(TClPP)] (7). These observations clearly show the importance of the number and positions of substituents on the phthalocyanine ligand in controlling the nature of the (phthalocyaninato)- (porphyrinato) rare-earth double-deckers obtained. In particular, α-alkoxylation of the phthalocyanine ligand is found to stabilize the protonated form, a fact supported by molecular-orbital calculations. A combination of mass spectrometry, NMR, UV-visible, near-IR, MCD, and IR spectroscopy, and X-ray diffraction analyses, facilitated the differentiation of the newly prepared neutral nonprotonated and protonated double-decker complexes. The crystal structure of the protonated form has been determined for the first time. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.