Hydrogen bonded lambda-shaped packing motif based on 4-nitrophenylhydrazones: a promising design tool for engineering acentric crystals
- 1 January 1997
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of Materials Chemistry
- Vol. 7 (10) , 2021-2026
- https://doi.org/10.1039/a702339a
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.Keywords
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