Axially Chiral Facial Amphiphiles with a Dihydronaphthopentaphene Structure as Molecular Tweezers for SWNTs

Abstract

Syntheses of chiral 6,15-dihydronaphtho[2,3-c]pentaphene derivatives of opposite configurations are reported. Starting from anthracene, the strategy involves two key steps: a Diels-Alder reaction on a prochiral dianthraquinone, and an enantiomeric resolution using (-)-menthol. The final molecules exhibit very strong optical activity, as shown by their circular dichroism spectra, and are examples of chiral facial amphiphiles. Their adsorption at the surface of single-walled carbon nanotubes (SWNTs) has also been studied, and has been found to occur preferentially on 0.8-1.0 nm diameter nanotubes among the population of a high-pressure CO conversion (HiPco) SWNT sample (0.8-1.2 nm). The synthesised facial amphiphiles act as nano-tweezers for the diameter-selective solubilisation of SWNTs in water. The expected optical activities of the SWNT samples solubilised by each of the chiral amphiphiles have been studied by circular dichroism spectroscopy, but the results are not yet conclusive.

Late stage modification of receptors identified from dynamic combinatorial libraries

“…Our initial attempts at modifying the carboxylates focused on single step couplings using traditional amide coupling reagents. Like others before us, 28,29 we observed poor reactivity of the carboxylates on A and N , which has been suggested to be due to steric constraints at the bridging olefin position. Thus, we were surprised to discover that both monomers can easily be converted to their corresponding N-hydroxysuccinimidyl (NHS) esters by coupling NHS using dicyclohexylcarbodiimide (DCC) in DCM ( Trt-A/N-OSu ).…”

“…28,29 Using this method, we showed that we could di-functionalize each monomer with Gly to yield Gly-A and Gly-N , which were used in DCLs to assemble the novel receptors A 2 Gly-N , Gly-A 2 N , and Gly-A 2 Gly-N . As only the Gly-spaced monomer is reactive under the coupling conditions developed for A 2 B , A 2 D and A 2 G , we were able to demonstrate the selective functionalization of N in a similar manner by coupling Biotin-PEG 2 -NH 2 to A 2 Gly-N to form A 2 N-Biotin .…”

Optical Resolution of Single-Walled Carbon Nanotubes through Molecular Recognition with Chiral Diporphyrin Nanotweezers

“…2830 Relatively small molecules have also been applied to the separation of SWNTs through discrimination of a specific (n,m) structure. 23,24,31,32 In this review, we would like to introduce a novel method for the separation of SWNTs according to handedness through molecular recognition with gable-type chiral diporphyrins, developed recently in our group. 4,3335…”

The Potential of Perylene Bisimide Derivatives for the Solubilization of Carbon Nanotubes and Graphene

“…In principle, a rigid unit bridging two aromatic anchor groups such as pentacene tweezer 3 [ 122 ] or dihydronaphthopentaphene tweezer 4 [ 123 ] results in the formation of tweezer-type molecules capable of selectively interacting with the SWCNT scaffold. Responding to a growing interest, the experimental results have furthermore been supported by density functional theory calculations.…”