Publication
Title
Tribenzotriquinacene receptors for fullerene rotors : towards symmetrical chiral stators for unidirectionally operating nanoratchets
Author
Abstract
The synthesis of a stereochemically pure concave tribenzotriquinacene receptor (7) for C-60 fullerene, possessing C-3 point group symmetry, by threefold condensation of C-2-symmetric 1,2-diketone synthons (5) and a hexaaminotribenzotriquinacene core (6) is described. The chiral diketone was synthesized in a five-step reaction sequence starting from C-2h-symmetric 2,6-di-tert-butylanthracene. The highly diastereo-discriminating Diels-Alder reaction of 2,6-di-tertbutylanthracene with fumaric acid di(-)menthyl ester, catalyzed by aluminium chloride, is the relevant stereochemistry introducing step. The structure of the fullerene receptor was verified by H-1 and C-13 NMR spectroscopy, mass spectrometry and single crystal X-ray diffraction. VCD and ECD spectra were recorded, which were corroborated by ab initio DFT calculations, establishing the chiral nature of 7 with about 99.7% ee, based on the ee (99.9%) of the chiral synthon (1). The absolute configuration of 7 could thus be established as all-S [(2S,7S,16S,21S,30S,35S)-(7)]. Spectroscopic titration experiments reveal that the host forms 1: 1 complexes with either pure fullerene (C-60) or fullerene derivatives, such as rotor 1'-(4-nitrophenyl)-3'-(4-N,N-dimethylaminophenyl)-pyrazolino[4',5':1,2][60]fullerene (R). The complex stability constants of the complexes dissolved in CHCl3/CS2 (1:1 vol.%) are K([C-60 subset of 7])= 319(+/- 156) M-1 and K([R subset of 7])= 110(+/- 50) M-1. With molecular dynamics simulations using a first-principles parameterized force field the asymmetry of the rotational potential for [R subset of 7] was shown, demonstrating the potential suitability of receptor 7 to act as a stator in a unidirectionally operating nanoratchet.
Language
English
Source (journal)
Chemistry: a European journal. - Weinheim
Publication
Weinheim : 2014
ISSN
0947-6539
Volume/pages
20:29(2014), p. 9100-9110
ISI
000339386700041
Full text (Publishers DOI)
Full text (publishers version - intranet only)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identification
Creation 08.09.2014
Last edited 29.04.2017
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