Abstract
Reaction between the optically active metal‐free phthalocyanine with a π system with noncentrosymmetrical C~2v~ symmetry ((S)‐ and (R)‐H~2~{Pc(OBNP)~2~}; OBNP=binaphthylphthalocyanine) and half‐sandwich complexes [M^III^(acac)(TClPP)] (M=Y, Eu; TClPP=meso‐tetrakis(4‐chlorophenyl)porphyrinate; acac=acetylacetonate), which were generated in situ from [M(acac)~3~]⋅n H~2~O and H~2~(TClPP) in n‐octanol at reflux, provided the first optically active protonated mixed phthalocyaninato–porphyrinato rare‐earth double‐decker complexes [M^III^H{Pc(OBNP)~2~}(TClPP)] (M=Y, Eu) in good yield. In addition to electronic absorption spectroscopy and magnetic circular dichroism results, circular dichroism shows different spectroscopic features of these mixed‐ring rare‐earth double‐decker compounds in different solvents, such as DMF and CHCl~3~, which was well‐reproduced on the basis of time‐dependent density functional theory calculation results for the yttrium species (S)‐[Y^III^{Pc(OBNP)~2~}(Por)]^−^ (Por=porphyrinate, which is obtained by removing the four chlorophenyl groups from the TClPP ligand) in terms of the change in the rotation angle between the two macrocyclic ligands in the double‐decker molecules. These results revealed the solvent‐dependent nature of the molecular conformation of mixed‐ring rare‐earth double‐decker complexes, which suggests a new way of tuning the optical and the electrochemical properties of sandwich‐type bis(tetrapyrrole)–metal double‐decker complexes in solution by changing the solvent.