Chiral bis(phthalocyaninato) yttrium double-decker complexes. Synthesis, structure, spectroscopy, and electrochemistry

Abstract

Two new chiral sandwich-type bis(phthalocyaninato) yttrium double-decker complexes including the homoleptic species (R)- and (S)-Y[Pc(OBNP)₄]₂ (1) and a heteroleptic analogue (R)- and (S)-Y(Pc)[Pc(OBNP)₄] (2) {Pc = unsubstituted phthalocyaninate; [Pc(OBNP)₄] = tetrakis(dinaphtho[1,2-e:1′,2′-g]-1,4-(dioxocine)[2,3-b;2′,3′-k;2′′,3′′-t;2′′′,3′′′-c′]phthalocyaninate)} have been synthesized and spectroscopically characterized. In particular, the molecular structures of (R)- and (S)-1 were determined on the basis of single crystal X-ray diffraction analysis, representing the first structurally characterized chiral bis(phthalocyaninato) rare earth double-decker complexes. Perfect mirror-image CD signals observed in the whole phthalocyanine absorption range of the CD spectra of the (R)- and (S)-enantiomers for both compounds reveal the effective chiral information transfer from the peripheral binaphthyl moieties to the phthalocyanine chromophore, while the difference observed in the CD spectrum between 1 and 2 indicates the effect of the chiral substituent number on the chiral information transfer. Nevertheless, the absolute structures unambiguously elucidated for both enantiomers of the homoleptic double-decker render it possible to clarify the chirality of optically active bis(phthalocyaninato) rare earth compounds.