Dicarba[26]hexaporphyrinoids(1.1.1.1.1.1) with an Embedded Cyclopentene Moiety—Conformational Switching

Abstract

Incorporation of cyclopentene fragments into a skeletono fp arental[ 26]hexaphyrin(1.1.1.1.1.1) afforded extended carbaporphyrinoids:3 1,34-dicarbahexa[26]chlorin and its derivatives:t he first externally substituted by ethoxy and 2,4,6-trimethylbenzylidene groups and the second one formed by selective oxidation of one cyclopentenering. Macrocycles adopt dumbbell-shaped conformationsw ith two meso hydrogen atoms located inside the macrocyclic cavity. Protonation of 31,34-dicarba[26]hexachlorins provided dicationse xisting in dumbbellshaped and rectangularc onformations.

21-Carba-23-oxaporphyrinoids and 21-oxo-21-carba-23-oxaporphyrinoids: macrocyclic π-conjugation involving the carbonyl moiety

“…Thus, the C(21)H 2 resonance with the intensity of two hydrogens, scalar coupled to H(2,3), has been identified at −7.43 ppm. The HSQC experiment reveals the tetrahedral nature of this carbon consistently with its 13 C chemical shift equal to 28.4 ppm. The analogous protonation of the internal C( 21) carbon has been previously detected for 21-carba-23-thiaporphyrin, 23 or β-alkylated 21-carbaporphyrin, 19 benzocarbaporphyrin, 49 and N-confused porphyrin.…”

“…Here, it is essential to note that 15 and 16 potentially provide the core of a similar size but with different (−2 vs. −3) anionic charges. Still, complete characterization using the typical methodology (UV-vis, 1 H NMR, and 13 C NMR) was carried out, setting the spectroscopic reference point for further explorations.…”

“…The 1 H NMR spectrum of 21-oxo-21-carba-23-oxaporphyrin 17 covers an entirely different range of chemical shifts compared to 14 or 18. The 1 H NMR spectrum of 17 shows two singlets at 6.38 and 6.42 ppm assigned to meso-hydrogens H(5,20) and furan ring protons H (12,13), respectively (Fig. 7, trace C).…”

“…9,10 The synthesis of N-confused porphyrin prompted significant interest in the broader and very original group of macrocycles, 21-carbaporphyrins, to be eventually widened on the whole macrocyclic class of carbaporphyrinoids, which has also included carbacorroles 11,12 and expanded carbaporphyrins. 13,14 Several advances in the field are comprehensively accounted in a series of recent review articles. [15][16][17][18] Initially, the formation of 21-carbaporphyrin 2the carba analogues of octaethylporphyrin (OEP)H 2was achieved by Berlin 5 via [3 + 1] condensation.…”

The Intracavity Extension of 28-Hetero-2,7-naphthiporphyrins in Reactions with Alkylamines

“…Among the vast class of carbaporphyrinoids, those incorporating two and more carbon atoms within the cavity remain rare. − Examples of such systems include naphthiporphyrins, namely, carbaporphyrinoids incorporating at least one naphthalene moiety replacing the pyrrole ring in the porphyrin macrocycle. − Recently, we have demonstrated that the horizontal expansion of the m -benziporphyrin , framework could provide the 28-hetero-2,7-naphthiporphyrins 1-X (X = S, Se, Te), which act as macrocyclic ligands for phosphorus­(V). , …”