Self-association of poly(aramide) dendrimers

Abstract

Two poly(aramide) dendrimers, which possess electron-deficient 1,3,4-oxadiazole and aromatic systems linked by amide units to a triphenylmethane core, strongly self-associate in chloroform solution through hydrogen bonding.

References

1. For a recent monograph on dendrimers, see G. R. Newkome, C. N. Moorefield and F. Vögtle, Dendritic Molecules: Concepts, Synthesis, Perspectives, VCH, Weinheim, 1996.
2. S. C. E. Backson, P. M. Bayliff, W. J. Feast, A. M. Kenwright, D. Parker and R. W. Richards, Macromol. Symp., 1994, 77, 1.
3. Y. H. Kim, J. Am. Chem. Soc., 1992, 114, 4947.
4. A. Kraft, Chem. Commun., 1996, 77.
5. Application of 1,3,4-oxadiazole derivatives in electroluminescent devices: Y. Hamada, C. Adachi, T. Tsutsui and S. Saito, Jpn. J. Appl. Phys., 1992, 31, 1812; A. R. Brown, D. D. C. Bradley, J. H. Burroughes, R. H. Friend, N. C. Greenham, P. L. Burn, A. B. Holmes and A. Kraft, Appl. Phys. Lett., 1992, 61, 2793.
6. X.-C. Li, A. Kraft, R. Cervini, G. C. W. Spencer, F. Cacialli, R. H. Friend, J. Grüner, A. B. Holmes, J. C. DeMello and S. C. Moratti, Mater. Res. Soc. Symp. Proc., 1996, 413, 13.
7. J. Bettenhausen and P. Strohriegl, Adv. Mater., 1996, 8, 507; J. Bettenhausen and P. Strohriegl, Makromol. Chem., Commun., 1996, 17, 623.
8. D. Hellwinkel and H. Fritsch, Chem. Ber., 1990, 123, 2207.
9. For other syntheses of poly(aramide)s by palladium-catalysed carbonylations, see M. Yoneyama, M. Kakimoto and Y. Imai, Macromolecules, 1988, 21, 1908; S. R. Turner, R. J. Perry and R. W. Blevins, Macromolecules, 1992, 25, 4819; V. R. Reichert and L. J. Mathias, Macromolecules, 1994, 27, 7024.
10. S. Ahrland, J. Chatt, N. R. Davies and A. A. Williams, J. Chem. Soc., 1958, 276.
11. N. Yamazaki, M. Matsumoto and F. Higashi, J. Polym. Sci., Polym. Chem. Ed., 1975, 13, 1373.
12. Until now, dendrimer–dendrimer interactions involved mainly micelle formation, aggregation or self-assembly in solution, and liquidcrystalline phase transition in the absence of solvent: G. R. Newkome, C. N. Moorefield, G. R. Baker, R. K. Behera, G. H. Escamillia and M. J. Saunders, Angew. Chem., Int. Ed. Engl., 1992, 31, 917; J. M. J. Fréchet and I. Gitsov, Macromol. Symp., 1995, 98, 441; V. Percec, P. Chu, G. Ungar and J. Zhou, J. Am. Chem. Soc., 1995, 117, 11441; J. C. M. van Hest, D. A. P. Delnoye, M. W. P. L. Baars, C. Elissen-Román, M. H. P. van Genderen and E. W. Meijer, Chem. Eur. J., 1996, 2, 1616; S. C. Zimmerman, F. Zeng, D. E. C. Reichert and S. V. Kolotuchin, Science, 1996, 271, 1095.
13. R. B. Martin, Chem. Rev., 1996, 96, 3043.
14. N. Veldman, A. L. Spek, J. J. H. Schlotter, J. W. Zwikker and L. W. Jenneskens, Acta Crystallogr., Sect. C, 1996, 52, 174.
15. For hydrogen-bonding in aramides and attractive π-interactions between electron-poor aromatic compounds, see A. P. Bisson and C. A. Hunter, Chem. Commun., 1996, 1723; C. A. Hunter and J. K. M. Sanders, J. Am. Chem. Soc., 1990, 112, 5525.