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Metal Complexes with Tetrapyrrole Ligands, LVIII. Zirconium(IV) and Hafnium(IV) Bisporphyrinate Double Deckers: Synthesis, Spectra, Redox Potentials, and Structure
Author(s) -
Buchler Johann W.,
Cian André De,
Fischer Jean,
Hammerschmitt Peter,
Weiss Raymond
Publication year - 1991
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19911240511
Subject(s) - chemistry , porphyrin , zirconium , redox , cerium , cyclic voltammetry , metal , ligand (biochemistry) , tetrapyrrole , inorganic chemistry , ionic radius , absorption spectroscopy , crystallography , ionic bonding , photochemistry , electrochemistry , organic chemistry , ion , biochemistry , physics , receptor , electrode , quantum mechanics , enzyme
The synthesis of new zirconium and hafnium bisporphyrinate double deckers M(P) 2 (MZr, Hf; POEP, TPP) 2,3) is described. The complexes are characterized by UV/Vis/NIR and 1 H‐NMR spectroscopy and cyclic voltammetry. As compared with MCe, the redox potentials or the energies of the nearinfrared absorption bands of the corresponding radical cations [M(P) 2 ] + are lower by ≈ 0.2 V or higher by ≈ 2000 cm −1 , respectively, Hence, there is a stronger π‐π interaction between the porphyrin ligands as compared with the cerium analogues due to the smaller ionic radii of Zr(IV) and Hf(IV). X‐ray crystallography of Zr(TPP) 2 confirms the sandwich‐like structure of the compound and the close proximity of the porphyrin ligands.