Doubly N‐Confused [36]Octaphyrin(1.1.1.1.1.1.1.1): Isomerization, Bis‐Metal Coordination, and Topological Chirality

Abstract

A novel [36]octaphyrin analogue embedding two N-confused pyrrole units demonstrated unique prototropy-coupled isomerization between the Figure-of-eight and dumbbell conformers. Upon bis-metal coordination, fixation of fully π-conjugated Figure-of-eight structures was achieved as referred from the X-ray crystal structure. Chirogenesis of the helical enantiomers was proved by intense circular dichroism (CD) response in the near infrared (NIR) region.

Conformation‐Dependent Response to the Protonation of Diphenanthrioctaphyrin(1.1.1.0.1.1.1.0): A Route to Pseudorotaxane‐Like Structures

“…The rotationo ft he heterocyclic subunit forced the concerted movement of 21,42meso-Ph, whose ortho-protons demonstrated dipolar coupling with the H (43,49) of the phenanthrene. The inversion of the pyrrole was further supported by the NOE cross-peaks linking the b-positions of the heterocycle, that is, H (19,40) with o-Ph (21,42), and H (18,39) with H (47,53). In addition, the crosspeak between H(2,23)a nd o-Ph (21,42) suggested ac lose distance between these two protons.…”

“…[10,11] The growingi nterest that these macrocyclesh aves tarted to receive results from their intriguing electronic structures, [12][13][14] peculiar reactivity, [15] Mçbiusa romaticity, [16][17][18] stereochemical properties, [15,19] and, finally,t heir conformational flexibility. [20,21] Recently,a na lluring area of research has flourished employing expanded carbaporphyrinoids for the constructiono fs upramolecular systems. [22][23][24][25] Over the last few years, we have developed ag roup of macrocycles whiche ncompass phenanthrenylene subunits,t hat is, phenanthricorrole, [26][27][28] 32-heterophenanthrisapphyrins, [29] and helicenophyrins.…”

“…Recently,F uruta and co-workers have reported on doubly N-confused octaphyrin which demonstrated prototropy-coupled isomerization resulting in the transformation of the Figure-eightm acrocycle into ad umbbell isomer. [21] Chandrashekar and co-workers described hexathiaoctaphyrin, for which two rotational isomers were identified in the solids tate. [38] Sessler and co-workersd emonstratedp yr-role/pyridine dodecaphyrin which in solution exists as two figure-eight isomersundergoing fast exchange.…”

Expandierte Carbaporphyrinoide

“…Bei der Kondensation des N-fehlgeordneten Pentapyrrans mit N-fehlgeordnetem Tr ipyrrandicarbinol und einer anschließenden DDQ-Oxidation entstand das zweifach N-fehlgeordnete [36]Octaphyrin 75 (Schema 13). [77] [80] Der Makrocyclus nimmt eine Konformation an, bei der drei Carbonylgruppen in Richtung des makrocyclischen Kerns weisen, was die sterischen Zwänge und die Stabilisierung über ein Netzwerk von intramolekularen Wasserstoffbrücken widerspiegelt.…”

Expanded Carbaporphyrinoids

“…Thec ondensation of Nconfused pentapyrrane with N-confused tripyrrane dicarbinol followed by oxidation with DDQ produced doubly N-confused [36]octaphyrin 75 (Scheme 13). [77] Non-aromatic 75 adopts af igureof-eight conformation with two pyrrole rings located at the crossing, as evidenced by 1 HNMR spectroscopy and the X-ray crystallography ( Figure 3). However, the framework of the macrocycle was found to be flexible,u ndergoing conformational rearrangement in CH 2 Cl 2 solution even at 298 K.…”