ISMSC 2007 - Università degli Studi di Pavia
ISMSC 2007 - Università degli Studi di Pavia
ISMSC 2007 - Università degli Studi di Pavia
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PSB 25<br />
A Minimalist Design for Self-Assembled Rosette Nanotubes based on<br />
Mascal’s Motif<br />
Martins Oderinde, Grigory Tikhomirov and Hicham Fenniri*<br />
National Institute for Nanotechnology (NINT-NRC), Department of Chemistry,<br />
University of Alberta, 11421 Saskatchewan Dr, Edmonton, Alberta T6G 2M9, Canada<br />
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Rosette of 1<br />
G/C base 1, based on Mascal’s motif, was synthesized and its ability to self-assemble into<br />
rosette nanotubes in water was investigated. This presentation will focus on the synthesis and<br />
characterization of compound 1 by SEM, TEM, AFM and UV-VIS. Consistent with the calculated<br />
<strong>di</strong>ameter of 2.2 nm, the TEM-measured <strong>di</strong>ameter of a single tube was 2.2 0.2 nm. This value<br />
is also consistent with height profiles obtained from TM-AFM images, which give slightly<br />
compressed <strong>di</strong>ameter of 2.0 0.2 nm.<br />
[1] (a) Fenniri, H.; Mathiavanan, P.; Vidale, K. L.; Sherman, D. M.; Hallenga, K.; Wood, K. V.;<br />
Stowell, J. G. J. Am. Chem. Soc. 2001, 123, 3854-3855. (b) Fenniri, H.; Deng, B. L.; Ribbe, A.<br />
E. J Am. Chem. Soc. 2002, 124, 11064-11072. (c) Fenniri, H.; Deng, B. L.; Ribbe, A. E.;<br />
Hallenga, K.; Jacob, J.; Thiyagarajan, P. Proc. Natl. Acad. Sci. U.S.A. 2002, 99, 6487-6492.<br />
[2] (a) Mascal, M.; Hext, N.; Warmuth, R.; Moore, M. H.; Turkenburg, J. P. Angew. Chem. 1996,<br />
35, 2204-2206. (b) Mascal, M.; Farmer, S. C.; Arnall-Culliford, J. R. J. Org. Chem. 2006, 71,<br />
8146-8150<br />
PSB 26<br />
Chemically-Responsive Sol-Gel Transition of Supramolecular Single-Walled<br />
Carbon Nanotubes (SWNTs) Hydrogel Made by SWNTs-Cyclodextrins<br />
Hybrids<br />
Tomoki Ogoshi a , Tada-aki Yamagishi a , Yoshiaki Nakamoto a , and Akira Harada b<br />
a<br />
Department of Chemistry and Chemical Engineering, Graduate School of Natural Science and<br />
Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan and<br />
b<br />
Department of Macromolecular Science, Graduate School of Science, Osaka University,<br />
Toyonaka, Osaka 560-0043, Japan<br />
Single-walled carbon nanotubes (SWNTs) have received a great deal of interests because of<br />
their unique structural, electrical, and mechanical properties. However, their applications have<br />
been extremely limited due to their low solubility in solvents. Therefore, solubilization of SWNTs<br />
has been one of hot topics for the past few years. Soluble SWNTs in aqueous me<strong>di</strong>a are<br />
obtained using interaction between pyrene having ionic groups and SWNTs. Herein, we<br />
report novel chemically-responsive supramolecular SWNT hydrogel by using soluble SWNTs<br />
functionalized cyclodextrin (CD) moieties on SWNT surface. Since CD shows high solubility in<br />
water, water-soluble SWNTs carrying CDs are obtained by using interaction between<br />
pyrene mo<strong>di</strong>fied -CDs and SWNTs (Py--CD/SWNT hybrids) [1].<br />
By utilizing host-guest interactions between poly(acrylic acid) carrying dodecyl groups (PAA2)<br />
and -CDs of Py--CD/SWNT hybrids, nanocomposites of polymer and SWNTs were prepared.<br />
By mixing Py--CD/SWNT hybrids and PAA2 in aqueous me<strong>di</strong>a (Scheme 1a), a homogeneous<br />
SWNT hydrogel formed, in<strong>di</strong>cating that host-guest complexes between -CD moieties<br />
immobilized on the SWNT surface and dodecyl groups in PAA2 act as cross-links to form<br />
network structures which showed gel-like behavior. Furthermore, SWNT hydrogels composed of<br />
Py--CD/SWNT hybrids and PAA2 changed to sol by ad<strong>di</strong>ng competitive guests or host<br />
compounds. When so<strong>di</strong>um adamantane carboxylate (AdCNa, 100 eq. to dodecyl moieties of<br />
PAA2) was added to the hydrogel as a competitive guest, gel to sol transition was observed<br />
(Scheme 1b). This result in<strong>di</strong>cates <strong>di</strong>ssociation of the host-guest complexes between -CDs of<br />
Py--CD/SWNT hybrids and dodecyl groups of PAA2 because AdCNa strongly interacts with -<br />
CD compared with dodecyl group. Upon ad<strong>di</strong>tion of -CD (100 eq. to dodecyl groups of PAA2)<br />
as a competitive host, the gel also changed to sol (Scheme 1c). It is because dodecyl moieties<br />
form complexes with -CD more favorably than with -CD.<br />
(b) (a)<br />
(c)<br />
+<br />
+ -CD<br />
sol<br />
gel<br />
sol<br />
Supramolecular SWNT Hydrogel<br />
Scheme 1. Supramolecular SWNT Hydrogel Prepared from Py--CD/SWNT Hybrids and<br />
Guest Mo<strong>di</strong>fied Polymer (PAA2).<br />
[1] Ogoshi, T. et al. J. Am. Chem. Soc. <strong>2007</strong>, in press.<br />
PAA2<br />
Py--CD