Fully Conjugated [4]Chrysaorene. Redox-Coupled Anion Binding in a Tetraradicaloid Macrocycle

Abstract

Chrysaorene, a fully conjugated carbocyclic coronoid, is shown to be a low-bandgap π-conjugated system with a distinct open-shell character. The system shows good chemical stability and can be oxidized to well-defined radical cation and dication states. The cavity of [4]chrysaorene acts as an anion receptor toward halide ions with a particular selectivity toward iodides (K a = 207 ± 6 M −1 ). The interplay between anion binding and redox chemistry is demonstrated using a 1 H NMR analysis in solution. In particular, a well-resolved, paramagnetically shifted spectrum of the [4]chrysaorene radical cation is observed, providing evidence for the inner binding of the iodide. The radical cation−iodide adduct can be generated in thin solid films of [4] chrysaorene by simple exposure to diiodine vapor.

5,10-Dimesityldiindeno[1,2-a:2′,1′-i]phenanthrene: a stable biradicaloid derived from Chichibabin's hydrocarbon

“…The use of the phenanthrene ring system for elaboration of open-shell aromatics has so far been limited, with a single example provided by the recently reported [4]chrysaorene, a fully conjugated coronoid ring system with a tetraradicaloid character. 30,31 Diffractionquality crystals of 2 were grown without difficulty, and the structure of the new hydrocarbon was unambiguously conrmed using X-ray crystallographic analysis.…”

A macrocyclic oligofuran: synthesis, solid state structure and electronic properties

“…Introduction p-Conjugated macrocycles with well-dened diameters have received signicant attention in the last few decades, mainly because of their unique optical and electronic properties, their host-guest capabilities, and their potential as building blocks for supramolecular materials. [1][2][3][4][5][6] Many p-conjugated macrocyclic systems aggregate into columnar structures, 4,7-11 producing molecular channels that, with the appropriate inner-core functionalization, may give rise to ion channels, rod-like micellar aggregates, and even reaction chambers. [12][13][14][15] A particularly intriguing class of p-conjugated macrocycles is macrocyclic oligothiophenes (C-nT, Chart 1), introduced by Bäuerle's group in sizes ranging from C-8T to C-35T.…”

Shaping a Porphyrinoid Frame by Heteroatoms Extrusion: Formation of an Expanded [22]Triphyrin(6.6.0)

“…In contrast, the cavity of neutral 2 has hydrogen‐bond donors (N−H and C−H) and acceptors (N), forming a crevice suitable for a water molecule and potentially other small polar molecules. With an array of four C−H bonds, 2 ‐H 2 2+ belongs to a relatively narrow class of anion‐binding receptors with CH groups, especially rare among porphyrinoids …”