Porphyrinatonickel(II)–Cyclopentene and Porphyrinatonickel(II)–Cyclopentadiene Hybrids: Zirconacyclopentadiene-Mediated Syntheses, Structures, and Mechanistic Study

The reaction of meso-formyl Ni­(II) porphyrin 1 with zirconacyclopentadiene 2 in the presence of AlCl₃ afforded four products 3, 4, 5, and 6 with a total yield of over 85%. The structures of these compounds are well-characterized by ¹H NMR an d¹³C NMR spectroscopy, HRMS, and X-ray single-crystal diffraction. The mechanism is proposed mainly on the basis of isotopic labeling experiments, which showed that a Friedel–Crafts-type reaction and β-H shift may be critical during the formation of 5 and 6.