Supramolecular organization of subphthalocyanines in Langmuir and Langmuir-Blodgett films

Abstract

Interfacial studies of a series of subphthalocyanine (SubPc) macrocycles 1-3, 5 and 6, differently substituted either in the periphery (with polar and donor groups) or in the axial position of the macrocycle (with a chlorine atom or a trihexylsiloxy group), have been carried out. Remarkable changes in the orientation of the macrocycles at the air/water interface have been observed by varying the number of polar groups in the periphery or adding a bulky group in the axial position. The morphology of the monolayers has been carefully studied by Brewster angle microscopy. Monolayers made of compounds 1-3 could be efficiently transferred onto hydrophobic substrates. LB films of SubPc 1 were characterized in detail by UV-VIS and IR spectroscopies, and X-ray diffraction and ellipsometry experiments. These studies indicate that the LB films of SubPc 1 are surely Y-type, formed by layers of a well-defined average thickness of ca. 16 Å. Preliminary studies on the nonlinear optical (NLO) properties of these materials have been carried out. In particular, second harmonic generation (SHG) experiments have been performed on LB films of SubPc 1.

References

1. Phthalocyanines, Properties and Applications, ed. C. C. Leznoff and A. B. P. Lever, VCH, Cambridge, 1989, 1993, 1996, vol. 1–4.
2. (a) K. Ohta, L. Jacquemin, C. Sirlin and J. Simon, New J. Chem., 1988, 12, 751; (b) J. F. van der Pol, E. Neeleman, J. W. Zwikker, R. J. M. Nolte and W. Drenth, Recl. Trav. Chim. Pays-Bas, 1988, 107, 615; (c) J. A. Duro, G. de la Torre and T. Torres, Tetrahedron Lett., 1995, 36, 8079; (d) M. J. Cook, J. Mater. Chem., 1996, 6, 677.
3. T. Verbiest, S. Van Elshocht, M. Kauranen, L. Hellemans, J. Sanauwaert, C. Nuckolls, T. J. Katz and A. Persoons, Science, 1998, 282, 913.
4. Langmuir-Blodgett Films, ed. G. Roberts, Plenum, New York, 1990.
5. (a) S. Baker, M. C. Petty, G. G. Roberts and M. V. Twigg, Thin Solid Films, 1983, 99, 53; (b) M. J. Cook, D. A. Mayes and R. H. Poynter, J. Mater. Chem., 1995, 5, 2233; (c) S. Peiffer, C. Mingotaud, C. Garrigou-Lagrange, P. Delhaes, A. Sastre and T. Torres, Langmuir, 1995, 11, 2705; (d) F. Armand, M. V. Martïnez-Dïaz, B. Cabezón, P.-A. Albouy, A. Ruaudel-Texier and T. Torres, J. Chem. Soc., Chem. Commun., 1995, 1673.
6. (a) M. Geyer, F. Plenzig, J. Rauschnabel, M. Hanack, B. del Rey, A. Sastre and T. Torres, Synthesis, 1996, 1139; (b) A. Sastre, B. del Rey and T. Torres, J. Org. Chem., 1996, 61, 8591.
7. (a) G. de la Torre, T. Torres and F. Agulló-López, Adv. Mater., 1997, 9, 265; (b) G. de la Torre, P. Vázquez, F. Agulló-López and T. Torres, J. Mater. Chem., 1998, 8, 1671.
8. (a) A. Sastre, T. Torres, M. A. Díaz-García, F. Agulló-López, C. Dhenaut, S. Brasselet, I. Ledoux and J. Zyss, J. Am. Chem. Soc., 1996, 118, 2746; (b) B. del Rey, U. Keller, T. Torres, G. Rojo, F. Agulló-López, S. Nonell, C. Martí, S. Brasselet, I. Ledoux and J. Zyss, J. Am. Chem. Soc., 1998, 120, 12808.
9. (a) M. A. Díaz-García, F. Agulló-López, A. Sastre, T. Torres, W. E. Torruellas and G. I. Stegeman, J. Phys. Chem., 1995, 99, 14988; (b) G. Rojo, A. Hierro, M. A. Díaz-García, F. Agulló-López, B. del Rey, A. Sastre and T. Torres, Appl. Phys. Lett., 1997, 1802; (c) G. Rojo, B. del Rey, F. Agulló-López and T. Torres, J. Appl. Phys., 1998, 84, 6507.
10. H. T. Nguyen, A. Bouchta, L. Navailles, P. Barois, N. Isaert, R. J. Twieg, A. Maaroufi and C. Destrade, J. Phys. II, 1992, 2, 1889.
11. S. Hénon and J. Meunier, Rev. Sci. Instrum., 1991, 62, 936.
12. N. Cuvillier, R. Bernon, J.-C. Doux, P. Merzeau, C. Mingotaud and P. Delhaes, Langmuir, 1998, 14, 5573.
13. A. Meller and A. Ossko, Monatsh. Chem., 1972, 103, 150.
14. P.-A. Albouy, J. Phys. Chem., 1994, 98, 8543.
15. J.-P. Bourgoin, F. Doublet, S. Palacin and M. Vandevyver, Langmuir, 1996, 12, 6473.
16. J. Reiche, U. Pietsch, H.-P. Fink and H. Lemmetuinen, Acta Polym., 1992, 43, 206.
17. L. Werner, W. Hill, F. Marlow, A. Glismann and O. Hertz, Thin Solid Films, 1991, 205, 58.