Megalo‐Cavitands: Synthesis of Acridane[4]arenes and Formation of Large, Deep Cavitands for Selective C70 Uptake

Abstract

Deep cavitands, concave molecular containers, represent an important supramolecular host class that has been explored for a variety of applications ranging from sensing, switching, purification and adsorption to catalysis. A major limitation in the field has been the cavitand volume that is restricted by the size of the structural platform utilized (diameter approx. 7 Å). We here report the synthesis of a novel, unprecedentedly large structural platform, named acridane[4]arene (diameter approx. 14 Å), suitable for the construction of cavitands with volumes of up to 814 Å 3 . These megalocavitands serve as size-selective hosts for fullerenes with mM to sub-μM binding affinity for C 60 and C 70 . Furthermore, the selective binding of fullerene C 70 in the presence of C 60 was demonstrated.

Recent advances in the synthesis and applications of macrocyclic arenes

“…Very recently, Tiefenbacher's group 43 reported the synthesis of acridane [4]arene 18, which consists of four acridane derivative subunits (Fig. 12).…”

Pseudo[n]-pillar[5]arenes: Synthesis, Structures, and Host–Guest Binding Properties

“…Inspired by the synthetic strategies of P­[ n ]­s, researchers have synthesized new macrocycles from the reaction of different alkoxy-substituted aromatic monomers and paraformaldehyde. This led to the rapid discovery of series of macrocycles, including biphenyl­[ n ]­arenes, prism­[ n ]­arenes, rhombicarene, pagoda­[ n ]­arenes, saucer­[ n ]­arenes, leggero pillar[5]­arenes, octopus[3]­arenes, acridane­[ n ]­arenes, methylene-bridged naphthotubes, and others, − over the last five years. In addition, the modification at phenylene sites, , methylene bridge, , or upper/lower rims , of P­[ n ]­s resulted in pillar­[ n ]­arene­[ m ]­quinones, tiara­[ n ]­arenes, and others. − …”

Intermolecular hydrogen bonding in calix[5]arene derived cavitands regulates the molecular recognition of fullerenes

“…Intermolecular hydrogen bonding in calix [5]arene derived cavitands regulates the molecular recognition of fullerenes † Rube ´n A ´lvarez-Yebra, ‡ Alba Sors-Vendrell ‡ and Agustı ´Lledo…”

“…We present a readily available calix [5]arene derived cavitand receptor that is stabilized in the closed cone conformer through intermolecular hydrogen bonding with methanol molecules. The receptor features a highly spherical aromatic surface that binds C 60 and C 70 fullerenes effectively, and the binding event can be regulated allosterically by the addition of methanol.…”