Hydrogen bonded lambda-shaped packing motif based on 4-nitrophenylhydrazones: a promising design tool for engineering acentric crystals

Abstract

Two newly developed 4-nitrophenylhydrazone derivatives, 4-diethylaminobenzaldehyde 4-nitrophenylhydrazone, DEANPH, and 5-bromothiophene-2-carbaldehyde 4-nitrophenylhydrazone, BTNPH, which exhibit very strong second harmonic signals that are three orders of magnitude greater than that of the urea standard were investigated by single crystal X-ray analysis. The structural comparison with three other strongly optically nonlinear hydrazones revealed that the hydrogen bond-directed lambda-shaped supramolecular assemblies are the key and fundamental bases of all these non-centrosymmetric crystal packings. The high occurrence within this class of acentric crystals is likely due to this hydrogen bonded lambda-shaped packing motif. Since the chromophores are preferentially arranged in a lambda-shape, the acentric crystals are generally optimized for second-order nonlinear optical effects such as second harmonic generation.

References

1. G. R. Desiraju, Crystal Engineering, Elsevier, Amsterdam, 1989.
2. G. M. J. Schmidt, Pure Appl. Chem., 1971, 27, 647.
3. G. R. Desiraju, Angew. Chem., Int. Ed. Engl., 1995, 2311.
4. V. A. Russell and M. D. Ward, Chem. Mater., 1996, 8, 1654.
5. J. C. MacDonald and G. M. Whitesides, Chem. Rev., 1994, 2383.
6. J. F. Nicoud and R. J. Twieg, in Nonlinear Optical Properties of Organic Molecules and Crystals, ed. D. S. Chemla and J. Zyss, Academic Press, Orlando, 1987, p. 227.
7. J. Jacques, A. Collet and S. H. Wilen, Enantiomers Racemates and Resolutions, Wiley, New York, 1981.
8. S. R. Marder and J. W. Perry, Adv. Mater., 1993, 5, 804.
9. M. C. Etter, G. M. Frankenbach and D. A. Adsmond, Mol. Cryst. Liq. Cryst., 1990, 187, 22.
10. C. B. Aakeröy and K. R. Seddon, Chem. Soc. Rev., 1993, 397.
11. M. S. Wong, F. Pan, V. Gramlich, C. Bosshard and P. Günter, Adv. Mater., 1997, 9, 554.
12. C. Serbutoviez, C. Bosshard, G. Knöpfle, P. Wyss, P. Prêtre, P. Günter, K. Schenk, E. Solari and G. Chapuis, Chem. Mater., 1995, 7, 1198.
13. M. S. Wong, U. Meier, F. Pan, C. Bosshard, V. Gramlich and P. Günter, Adv. Mater., 1996, 8, 416.
14. M. S. Wong, C. Bosshard, F. Pan and P. Günter, Adv. Mater., 1996, 8, 677.
15. M. J. S. Dewar, E. G. Zoebisch, E. F. Healy and J. P. Stewart, J. Am. Chem. Soc., 1985, 107, 3902.