Expanded Porphyrins: Intriguing Structures, Electronic Properties, and Reactivities

Abstract

The chemistry of expanded porphyrins, which are higher homologues of porphyrins, has been intensively explored for the last three decades. Expanded porphyrins exhibit structures, electronic properties, coordination chemistry, and reactivities that are entirely different from those of porphyrins. Through these studies, it has become increasingly apparent that expanded porphyrins are attractive in views of aromaticity and multimetal coordination, or as functional dyes, nonlinear optical materials, ion receptors, or stable organic radicals. As such, we have continuously witnessed the emergence of expanded porphyrins that exhibit unprecedented structures and properties, as is highlighted by the facile realization of Möbius aromatic and even antiaromatic systems with twisted molecular structures. In this Review, the recent progress of the chemistry of expanded porphyrins after the seminal Review by Sessler and Seidel in 2003 is presented.

Conjugated Macrocycles: Concepts and Applications

“…[156] Stę pień et al and Saito and Osuka recently summarized reviews on the synthesis, structures, aromaticity, electronic properties, coordination chemistry, and reactivities of expanded porphyrins. [157,158] Rambo and Sessler also summarized a review of oligopyrrole macrocycles as receptors and chemosensors for hazardous materials. [159] Bäuerle and co-workers recently reported the X-ray structure and electronic properties of cyclo [10]thiophene 119a.…”

Konjugierte Makrocyclen: Konzepte und Anwendungen

“…[156] Stę pień , LatosGrażyń ski et al sowie Saito und Osuka verçffentlichten umfassende Aufsätze über die Synthese, Strukturen, Aromatizität, elektronischen Eigenschaften, Koordinationschemie und Reaktivitäten von expandierten Porphyrinen. [157,158] Ein Aufsatz über Oligopyrrol-Makrocyclen für Rezeptoren und Chemosensoren wurde von Rambo und Sessler verçffent-licht. [159] Bäuerle und Mitarbeiter berichteten über die Rçntgen-struktur und elektronischen Eigenschaften des Cyclo- [10]thiophens 119a.…”

A Time-Dependent Density Functional Study of a Non-Aromatic [1.1.1.1.1]-Pentaphyrin and Its Lutetium Complex

“…3 The extension of the macrocycle cavity size with the inclusion of more than four pyrrole subunits brings a new class of polypyrrolic chromophores termed expanded porphyrins. 4,5 The first expanded porphyrin, discovered by Woodward et al in 1966 but reported with a full characterization only in 1983, was the sapphyrin, a pentapyrrolic macrocycle, whose name was assigned from its color. 6,7 A more general definition of expanded porphyrins, due to Sessler et al, implies the presence of heteroatom rings (thiophene, pyrrole, or furanlike) bonded directly or not through spacers, with at least 17 atoms in the main ring pathway.…”