Metal Complexes with Tetrapyrrole Ligands, LXVI. Synthesis, Characterization, and Variable‐Temperature 1H‐ and 19F‐NMR Investigations of Cerium(IV) Double‐Deckers Derived from Monofunctionalized Tetraarylporphyrins

The synthesis of a cerium(IV) bisporphyrinate 1b starting from (p‐hydroxyphenyl)tris(p‐tolyl)porphyrin 2b is described. Derived from 2b by substitution of the phenolic OH group, the monofunctionalized tetraarylporphyrins 2c‐f and their cerium(IV) sandwich complexes 1c‐f were synthesized. The complexes are characterized by UV/Vis, IR, and 1H‐NMR spectroscopy. 19F‐NMR spectra of 1f show the presence of a vicinal and a transversal isomer due to the rigid squareantiprismatic coordination geometry of cerium(IV) bisporphyrinates. Variable‐temperature 1H‐ and 19F‐NMR spectra were recorded to investigate the rotational rigidity of the double‐decker system. The spectra show that the vicinal and transversal isomers are stable up to 140°C, i.e. rotation of the two porphyrin macrocycles with respect to each other does not occur.