Selective Binding and Easy Separation of C₇₀ by Nanoscale Self‐Assembled Capsules

Abstract

All wrapped up: An easy, highly selective separation of C70 and the higher fullerenes has been achieved by solid–liquid extraction with a 2‐ureido‐4‐[1H]‐pyrimidinone‐based scaffold which wraps around the guest as a dimeric capsule (see picture), thereby solubilizing it in THF. Acidification disrupts the hydrogen‐bonding network and allows easy recovery of the guest and recycling of the receptor without chromatography or tedious procedures.

Molecular basis for the recognition of higher fullerenes into ureidopyrimidinonecyclotriveratrylene self-assembled capsules

“…Our in silico results are crucially supported by experimental data. Indeed, on top of accurately reproducing experimentally observed capsule selectivity towards fullerenes (preference for C84 over C70, and even more over C60), [14][15] our calculations are also able to correctly predict the preferred structural conformation of the 12 capsules as detected by NMR. Selectivity trends found by our calculations and previous experiments are here furthermore reconfirmed by racemization studies featuring CD spectroscopy.…”

“…We have previously conceived and synthesized a hydrogen-bonded, self-assembled dimeric capsule 12 that readily encapsulates fullerenes such as C60, C70, [14] and C84 [15] (Scheme 1). Each monomer 1 is constituted by a modified concave cyclotriveratrylene (CTV) platform, known for its complementarity to the convex surface of C60.…”

Variation of guest selectivity within [Fe4L4]8+ tetrahedral cages through subtle modification of the face-capping ligand

“…8 Moreover, the use of elec- studies. The structure of [2](NTf 2 ) 8 was refined in the monoclinic space group P2 1 /c (ESI † suggesting the guests 'lock-down' the ligand arms to inhibit their dynamic behaviour (Fig. 2).…”

Self-assembled Cages and Capsules Using Cyclotriveratrylene-type Scaffolds

“…19 Homodimeric capsules of type (2) 2 ¢F, where 2 is a tris(4-ureidopyrimidinone)-appended CTG and F is an encapsulated fullerene, have been reported by de Mendoza and co-workers (Chart 3). 5,20,21 Binding of the fullerene templates the capsule formation in solution. The system is selective for higher fullerenes and a combination of experimental and theoretical studies 5,21 have established that binding constants follow the trend C 90 µ C 84 > C 78 > C 76 > C 70 > C 60 .…”

“…5,20,21 Binding of the fullerene templates the capsule formation in solution. The system is selective for higher fullerenes and a combination of experimental and theoretical studies 5,21 have established that binding constants follow the trend C 90 µ C 84 > C 78 > C 76 > C 70 > C 60 . This has potential utility in the purification of higher fullerenes given that fullerene can be recovered from the (2) 2 ¢F adduct through a change in solvent polarity.…”