The University of Southampton
University of Southampton Institutional Repository

Reaction of C60F18 with diethyl bromomalonate: diversion of the Bingel reaction and formation of the first 18 pi annulenic fullerene

Reaction of C60F18 with diethyl bromomalonate: diversion of the Bingel reaction and formation of the first 18 pi annulenic fullerene
Reaction of C60F18 with diethyl bromomalonate: diversion of the Bingel reaction and formation of the first 18 pi annulenic fullerene
Reaction of C60F18 with diethyl bromomalonate in the presence of DBU results in the nucleophilic replacement of either one, two, or three of the most accessible fluorine atoms by CBr(CO2Et)(2) moieties, in preference to formation of a cyclopropanated derivative (the normal Bingel reaction). Substitution that:takes place delta to the departing fluorine, is the first proven example of S(N)2' substitution in a fullerene, and appears to be sterically driven. The ratio of mono-/poly-substitution products can be controlled by varying the rate of addition of the DBU land the molar ratio between C60F18 and the other reagents. The tri-substituted product is an [18]annulene, has an intense emerald-green colour ascribable to the electron delocalisation in the (equatorial) annulene belt (bond length variation 0.018 Angstrom), and has C-3v symmetry. This is the first example on an annulenic fullerene (moreover of an all-trans annulene or trannulene). The extent of substitution in each compound is identified from the fluorinated fragments (C60F15, C60F16, and C60F17, respectively, for tri-, di-, and mono-substitution) in the El mass spectra, and by their H-1 and F-19 NMR spectra. The structure of the tri-substituted [18]annulene was confirmed by single crystal X-ray diffraction. Normal Bingel cycloaddition also takes place between C60F18 and diethyl malonate-DBU in CBr4, to give C60F18C(CO2Et)(2) and C60F16C(Co2Et)(2) in relatively low yields. Calculations indicate a critical size of substituent required to produce delta-substitution, rather than ipso-substitution of the departing fluorine.
electron-affinities, mass-spectrometry, dyad
41-46
Wei, X. W.
d72b299f-7da9-4544-ab49-0c05b04c3300
Avent, A. G.
bd34ffe6-fea1-4e75-81fc-82ecaa0c0b5a
Boltalina, O. V.
c91e33b3-7da7-4481-95f4-92fce2a56e46
Darwish, A. D.
02f7b06f-73d1-497f-a74c-acefab0fdccc
Fowler, P. W.
ef41de08-2322-4b5f-ad11-fea288519277
Sandall, J.P.B.
7faa179f-0d4e-4ca4-a96f-b3ab2f30140d
Street, J. M.
186366c0-692b-4236-bb93-e2a3b6e9395c
Taylor, R.
1abcd415-ae2c-4e95-a761-6948ce7f4d32
Wei, X. W.
d72b299f-7da9-4544-ab49-0c05b04c3300
Avent, A. G.
bd34ffe6-fea1-4e75-81fc-82ecaa0c0b5a
Boltalina, O. V.
c91e33b3-7da7-4481-95f4-92fce2a56e46
Darwish, A. D.
02f7b06f-73d1-497f-a74c-acefab0fdccc
Fowler, P. W.
ef41de08-2322-4b5f-ad11-fea288519277
Sandall, J.P.B.
7faa179f-0d4e-4ca4-a96f-b3ab2f30140d
Street, J. M.
186366c0-692b-4236-bb93-e2a3b6e9395c
Taylor, R.
1abcd415-ae2c-4e95-a761-6948ce7f4d32

Wei, X. W., Avent, A. G., Boltalina, O. V., Darwish, A. D., Fowler, P. W., Sandall, J.P.B., Street, J. M. and Taylor, R. (2002) Reaction of C60F18 with diethyl bromomalonate: diversion of the Bingel reaction and formation of the first 18 pi annulenic fullerene. Journal of the Chemical Society, Perkin Transactions 2, (1), 41-46. (doi:10.1039/b105921c).

Record type: Article

Abstract

Reaction of C60F18 with diethyl bromomalonate in the presence of DBU results in the nucleophilic replacement of either one, two, or three of the most accessible fluorine atoms by CBr(CO2Et)(2) moieties, in preference to formation of a cyclopropanated derivative (the normal Bingel reaction). Substitution that:takes place delta to the departing fluorine, is the first proven example of S(N)2' substitution in a fullerene, and appears to be sterically driven. The ratio of mono-/poly-substitution products can be controlled by varying the rate of addition of the DBU land the molar ratio between C60F18 and the other reagents. The tri-substituted product is an [18]annulene, has an intense emerald-green colour ascribable to the electron delocalisation in the (equatorial) annulene belt (bond length variation 0.018 Angstrom), and has C-3v symmetry. This is the first example on an annulenic fullerene (moreover of an all-trans annulene or trannulene). The extent of substitution in each compound is identified from the fluorinated fragments (C60F15, C60F16, and C60F17, respectively, for tri-, di-, and mono-substitution) in the El mass spectra, and by their H-1 and F-19 NMR spectra. The structure of the tri-substituted [18]annulene was confirmed by single crystal X-ray diffraction. Normal Bingel cycloaddition also takes place between C60F18 and diethyl malonate-DBU in CBr4, to give C60F18C(CO2Et)(2) and C60F16C(Co2Et)(2) in relatively low yields. Calculations indicate a critical size of substituent required to produce delta-substitution, rather than ipso-substitution of the departing fluorine.

This record has no associated files available for download.

More information

Published date: 1 January 2002
Keywords: electron-affinities, mass-spectrometry, dyad

Identifiers

Local EPrints ID: 19869
URI: http://eprints.soton.ac.uk/id/eprint/19869
PURE UUID: 7d2c54f4-b3d3-4b1c-9290-c2fa32c6ca73

Catalogue record

Date deposited: 20 Feb 2006
Last modified: 15 Mar 2024 06:20

Export record

Altmetrics

Contributors

Author: X. W. Wei
Author: A. G. Avent
Author: O. V. Boltalina
Author: A. D. Darwish
Author: P. W. Fowler
Author: J.P.B. Sandall
Author: J. M. Street
Author: R. Taylor

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×