Metallkomplexe mit Tetrapyrrol-Liganden, LVI [1] / Metal Complexes with Tetrapyrrole Ligands, LVI [1]

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Abstract
The reaction of tris(2,4-pentanedionato)europium(III) with a porphyrin H2(P)** in boiling 1,2,4-trichlorobenzene affords a so-called “redox mixture” of europium(III) bisporphyrinates, i. e. porphyrin π-radicals of the type Eu(P)2 and sandwiches EuH(P)2 in which one of the porphyrin rings is protonated. Thus, from either tetraphenylporphyrin or its dilithium derivative, or octaethylporphyrin, or a mixture of both porphyrins, the corresponding mixtures of double-deckers with two identical or two differnt porphyrin rings are obtained. The transformation of the redox mixtures into the pure tetraphenylporphyrin derivatives Eu(TPP)2, EuH(TPP)2, and the salt [NBu4] [Eu(TPP),, the separation of the octaethylporphyrin derivatives Eu(OEP)2 and EuH(OEP)2, and the purification of the “mixed” double-decker Eu(OEP)-(TPP) are described. The compounds are characterized by cyclic voltammetry, IR, UV/VIS/NIR, 1H NMR, and mass spectra. The obtained data indicate that the π-electrons of the two porphyrin rings behave as a common electronic system in which a defect electron is delocalized. However, in the “mixed” double-decker Eu(OEP) (TPP) the defect electron is more concentrated on the OEP ring, i. e. the porphyrin ring which is more easily oxidized.

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