Expanded Porphyrin Contraction: From [22]Triphyrin(6.6.0) to [22]Triphyrin(6.5.0)

Abstract

An expanded triphyrin containing a bipyrrole moiety and annulene links, namely tetraphenyl‐[22]triphyrin(6.5.0), 2, has been synthesized. The synthesis proceeded by a postsynthetic transformation of tetraphenyl‐[22]triphyrin(6.6.0), 1, in a metal‐free unexpected and unprecedented ring contraction during column chromatography on alumina. The observed transformation, located at the hydrocarbon chain linking the pyrrole units, formally corresponds to a subtraction of one carbon atom from an annulene circuit. In contrast to the flexible substrate 1, the product 2 is conformationally rigid, and capable of chloride anion binding in its protonated form.

Recent advances in subphthalocyanines and related subporphyrinoids

“…707 [22]Triphyrin(6.6.0) ( 740 ) and [22]Triphyrin(6.5.0) ( 741 ) represent examples of what has been called expanded porphyrin contraction. 708,709 In 742 one of the meso -units consists of an aminoethoxy moiety, 710 while [18]triphyrins(4.1.1) containing ethyne ( 743 and 744 ) 711–713 or butadiene 714 bridges have been reported. All of these structures contain completely different macrocyclic cores and hence, new and diverse coordination chemistry.…”

“…128) consist of a [18]triphyrin(6.1.1) structure, 706 while triphyrin 739 consists of a [15]triphyrin(1.1.3) derivative. 707 708,709 In 742 one of the meso-units consists of an aminoethoxy moiety, 710 while [18]triphyrins(4.1.1) containing ethyne (743 and 744) [711][712][713] Fig. 126…”

Vacatadithiasapphyrins: Synthesis, Structure, and Spectral and Redox Properties

“…Very recently, Latos-Grazynski’s group used meso -tetraaryl 26,28-ditellurasapphyrin 8 to prepare [22]­triphyin(6.6.0) 9 by carrying out an acid-promoted tellurium extrusion reaction on 26,28-ditellurasapphyrins 8. Except for few research works on vacataporphyrinoids, − to the best of our knowledge, there is no other report available on vacataporphyrinoids to understand their novel and unusual physico-chemical properties and their potential use for various applications. This is because the tellurium-containing porphyrinoids are not easily accessible due to the unavailability of suitable tellurophene-based starting precursors and also partly due to inherent instability of tellurophene-containing porphyrinoids.…”