Low‐Valent Zirconocene‐Mediated Synthesis of Porphyrin(2.1.2.1)s and Its Extension to Synthesis of a Porphyrin(2.1.2.1) Nanobarrel

Abstract

Rosenthal's‐reagent‐mediated intramolecular cyclometallation of α,α‐dialkynyldipyrrin nickel(II) complex and subsequent acid treatment afforded a 1,3‐butadiene‐embedded porphyrin(2.1.2.1), 6, which served as a reactive diene towards dienophiles such as dimethyl acetylenedicarboxylate (DMAD) and benzyne to give corresponding Diels–Alder adducts. Diels–Alder reaction of 6 and benzdiyne gave adducts 14, 15 a, and 15 b along with a trace amount of porphyrin(2.1.2.1) barrel 13. Stepwise routes using 14 or 15 a/15 b as a substrate allowed for the synthesis of 13 as a single stereoisomer. The nanobarrel structure for 13 was revealed by X‐ray diffraction, where its cavity held two chloroform molecules via C−H⋅⋅⋅π interaction. DFT calculations revealed that the electrostatic attraction was dominant with binding energy of 32.8 kcal mol−1.

Pyrene-Bridged Expanded Carbaporphyrin Nanobelts

“…23−26 However, systems that combine PAHs and the free pyrrolic functionality characteristic of porphyrins in a single discrete molecular beltlike arrangement are essentially unknown. 27,28 Herein, we report two isomeric nanosized pyrene-containing carboporphyrin hybrids, NB1 and NB2 (Scheme 1), and show that these belt-like systems can be converted to their corresponding zinc complexes. Carbaporphyrins are porphyrin analogues (generally referred to as porphyrinoids) wherein one or more nitrogen donor atoms in the core is replaced by a carbon atom.…”