A Bis-exTTF Macrocyclic Receptor That Associates C<sub>60</sub> with Micromolar Affinity

Isla, Helena; Gallego, María; Pérez, Emilio M.; Viruela, Rafael; Ortı́, Enrique; Martín, Nazario

doi:10.1021/ja910107m

Cited by 94 publications

(67 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This strategy proved to be worthwhile, as macrocycle 18 b is one of the best fully organic receptors ever reported, with a binding constant of log K a = 6.5 in chlorobenzene, a very good solvent for fullerenes, and up to log K a = 7.5 in benzonitrile, a less competitive solvent. [32] We have thoroughly investigated the recognition properties of a whole family of exTTF-based macrocycles 18-20 by systematically modifying the spacer (p-phenylene, m-phenylene, and 2,6-naphthylene) and the alkenyl chain length (n = 1, 2, 3). [33] This study allowed us to discover some remarkably efficient macrocyclic hosts for fullerenes; for instance, 20 c binds C 70 with log K a = 6.1 in chlorobenzene at room temperature.…”

Section: P-extended Ttf-based Hostsmentioning

confidence: 99%

Wraparound Hosts for Fullerenes: Tailored Macrocycles and Cages

2011

Self Cite

View full text Add to dashboard Cite

Custom-made macrocyclic receptors for fullerenes are proving a valuable alternative to achieve the affinity and selectivity required to meet challenges such as the selective extraction of higher fullerenes, their chiral resolution, or the self-assembly of functional molecular materials. In this Minireview, we highlight some of the important breakthroughs that this class of fullerene hosts has already produced.

show abstract

Section: P-extended Ttf-based Hostsmentioning

confidence: 99%

Wraparound Hosts for Fullerenes: Tailored Macrocycles and Cages

2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…Although the host molecule would possess a rather flexible cavity, the evaluated association constants for fullerenes are considerably high (log K a ¼ 6.5 AE 0.5 M À1 for C 60 in PhCl, and the value for C 70 was unmeasurably large). The results would be due to high affinity of exTTF moieties for fullerene p surface (Figure 3.20) [77].…”

Section: Receptors Based On Bowl-shaped Conjugated Systemsmentioning

confidence: 99%

Receptors for Pristine Fullerenes Based on Concave–Convex π–πInteractions

Kawase

2012

Supramolecular Chemistry of Fullerenes and Carbon Nanotubes

View full text Add to dashboard Cite

In 1990, Kr€ atchmer and coworkers reported the extraction of fullerenes (C 60 and C 70 ) from carbon soot using aromatic solvents (Figure 3.1) [1]. After this discovery, receptor molecules for fullerenes have been extensively studied for separation and purification of fullerenes. Supramlecular chemists have found that traditional host molecules composed of electron-rich aromatic rings such as calix[n]arenes 1-4, oxacalix[3]arenes 5, and cyclotriveratrylenes (CTV) 6 ( Figure 3.2) can be employed for the purpose. The crystallographic analyses of these complexes with C 60 clearly indicated the importance of the p-p interactions between the convex p surface of C 60 and the concave p surface of the traditional host molecules. On the other hand, except a few examples, the traditional hosts bound fullerenes only in solid state. In order to bind with fullerenes more tightly, two strategies have been presented to construct the well preorganized p cavity so far. First, electron-rich aromatic units are introduced to the host molecule as appendants (Figure 3.2a). Second, two host molecules are linked by appropriate tether(s) to form a dimeric structure with a creft-, ring-, or ball-shaped cavity (Figure 3.2b). The binding abilities of the modified receptors fairly increased in comparison with those of simple traditional hosts. On the other hand, new receptors based on curved conjugated systems such as corannulene 7, extended TTF (exTTF) 8, and carbon nanorings (Figure 3.3) have been developed recently. These compounds possess a concave p surface matching to the convex surface of C 60 . Cyclic [6]paraphenyleneacetylene ([6]CPPA) 9 and the related compounds have smooth belt-shaped structure similar to a cut piece of carbon nanotube, and thus may be termed carbon nanorings. These receptors form stable inclusion complexes with fullerenes both in solution and in the solid state, and are good model compounds to explore the nature of the concave-convex p-p interactions. This chapter discusses the fullerene receptors bearing a cavity surrounded by p-orbitals, the so-called p cavity, the concept of molecular designs, and the nature of p-p interactions. The survey of the fullerene receptors should provide an insight into the supramolecular properties of curved conjugated systems. Although the receptor Supramolecular Chemistry of Fullerenes and Carbon Nanotubes, First Edition. Edited by Nazario Martin and Jean-Francois Nierengarten.

show abstract

“…Host platforms containing extended p-systems have been designed because of their affinity towards the sphere-like unsaturated structure of fullerenes. In this line, several covalent or supramolecular approaches pursued include: (a) macrocyclic arene-based receptors [18][19][20][21][22][23][24] , (b) macrocyclic structures containing aromatic heterocycles [25][26][27][28] , (c) p-extended TTF receptors [29][30][31][32][33] and (d) macrocyclic or jawlike structures containing porphyrin moieties 17,[34][35][36][37][38][39][40][41][42][43][44][45] . Interestingly, Fujita and co-workers reported the use of the empty channels of a metal-organic framework (MOF) for encapsulating fullerenes upon soaking MOF crystals in fullerene-containing toluene.…”

mentioning

confidence: 99%

Sponge-like molecular cage for purification of fullerenes

et al. 2014

View full text Add to dashboard Cite

Since fullerenes are available in macroscopic quantities from fullerene soot, large efforts have been geared toward designing efficient strategies to obtain highly pure fullerenes, which can be subsequently applied in multiple research fields. Here we present a supramolecular nanocage synthesized by metal-directed self-assembly, which encapsulates fullerenes of different sizes. Direct experimental evidence is provided for the 1:1 encapsulation of C 60 , C 70 , C 76 , C 78 and C 84 , and solid state structures for the host-guest adducts with C 60 and C 70 have been obtained using X-ray synchrotron radiation. Furthermore, we design a washingbased strategy to exclusively extract pure C 60 from a solid sample of cage charged with a mixture of fullerenes. These results showcase an attractive methodology to selectively extract C 60 from fullerene mixtures, providing a platform to design tuned cages for selective extraction of higher fullerenes. The solid-phase fullerene encapsulation and liberation represent a twist in host-guest chemistry for molecular nanocage structures.

show abstract

A Bis-exTTF Macrocyclic Receptor That Associates C₆₀ with Micromolar Affinity

Cited by 94 publications

References 22 publications

Wraparound Hosts for Fullerenes: Tailored Macrocycles and Cages

Wraparound Hosts for Fullerenes: Tailored Macrocycles and Cages

Receptors for Pristine Fullerenes Based on Concave–Convex π–πInteractions

Sponge-like molecular cage for purification of fullerenes

Contact Info

Product

Resources

About

A Bis-exTTF Macrocyclic Receptor That Associates C60 with Micromolar Affinity

Cited by 94 publications

References 22 publications

Wraparound Hosts for Fullerenes: Tailored Macrocycles and Cages

Wraparound Hosts for Fullerenes: Tailored Macrocycles and Cages

Receptors for Pristine Fullerenes Based on Concave–Convex π–πInteractions

Sponge-like molecular cage for purification of fullerenes

Contact Info

Product

Resources

About

A Bis-exTTF Macrocyclic Receptor That Associates C₆₀ with Micromolar Affinity