Towards True Carbaporphyrinoids: Synthesis of 21‐Carba‐23‐thiaporphyrin

Abstract

In the search for porphyrinoids with a built-in cyclopentadienyl moiety (true carbaporphyrins), a rational synthesis of carbathiaporphyrin, the synthons, has been elaborated. The donors (C,N,S,N) in the porphyrinic core of carbathiaporphyrinoids are potentially of fundamental importance for generating organometallic complexes, as exemplified through formation of the palladium(II) complex.

A Parallel‐Displaced Directly Linked 21‐Carba‐23‐Thiaporphyrin Dimer Incorporating a Dihydrofulvalene Motif

“…TheU V/Vis electronic absorption spectrum ( Figure 1) is consistent with aromaticity of 5.T he spectral features are related to those of 4, [11] considered here as ar eference.A Soret band is observed at the same position (417 nm), while the Qb ands at 687 and 758 nm are bathochromically shifted relative to 4 (651 and 718 nm), thus signifying the weak interaction between two carbaporphyrin subunits.…”

“…[10] They were generated by metal ion mediated contraction of p-phenylene or m-phenylene to cyclopentadiene,e mbedded in metal m-benziporphyrin (rhodium(III)) or p-benziporphyrin (palladium(II), gold(III) or rhodium(III)). [11] Introduction of the cyclopentadiene or cyclopentene fragments may be beneficial for the efforts aimed at welldefined modification of the macrocycle and construction of the new directly linked arrays demonstrating uncommon electronic properties and reactivity.Asapart of our research, aspired to explore the reactivity of carbaporphyrinoids, [12] here we report on the synthesis of bis(21-carbathiaporphyrin) with adirect sp 3 -sp 3 covalent linkage between internal carbon atoms and the unusual parallel-displaced geometry. [11] Introduction of the cyclopentadiene or cyclopentene fragments may be beneficial for the efforts aimed at welldefined modification of the macrocycle and construction of the new directly linked arrays demonstrating uncommon electronic properties and reactivity.Asapart of our research, aspired to explore the reactivity of carbaporphyrinoids, [12] here we report on the synthesis of bis(21-carbathiaporphyrin) with adirect sp 3 -sp 3 covalent linkage between internal carbon atoms and the unusual parallel-displaced geometry.…”

Synthesis and Metalation of Dimethoxybenziporphyrins, Thiabenziporphyrins, and Dibenziporphyrins

“…29 In a recent independent study, examples of palladium(II) complexes of a thiacarbaporphyrin (29a) and a thiacarbachlorin (29b) have been described. 30 The metalated structures reported in the present study gave powders or microcrystalline materials that were not well suited for structural analysis. However, the X-ray structure of 21a was obtained (Figure 11), and this established the presence of an organometallic Pd−C linkage and showed a uniquely distorted macrocyclic framework.…”

The development of artificial porphyrinoids embedded with functional building blocks

“…24 35 was prepared by [3+1] condensation of a mixture of isomeric tripyrrane 33 and thiophene diol. After first oxidation with p-chiloranil, a stable aromatic chlorine-like derivative 34 was obtained, and further careful oxidation with one equivalent of DDQ yielded the target 18-p cabathiaporphyrin 35.…”

“…2 are composed of two or more five-membered heterocycles that are linked at a or b position directly (20)(21)(22) or by unsaturated bridges (23,24). Permutation of pyrrole units in normal porphyrin by these larger-sized subunits usually leads to the expansion of a porphyrin framework into sapphyrin-, rubyrin-or hexaphyrin-like macrocycles.…”