Supramolecular Columnar Liquid Crystals with Tapered‐Shape Simple Pyrazoles Obtained by Efficient Henry/Michael Reactions |
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| Authors: | Hugo Blanco Verónica Iguarbe Prof. Joaquín Barberá Prof. José Luis Serrano Dr. Anabel Elduque Dr. Raquel Giménez |
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| Affiliation: | 1. Instituto de Ciencia de Materiales de Aragón (ICMA), Dpto de Química Orgánica, Facultad de Ciencias, CSIC—Universidad de Zaragoza, Zaragoza, Spain;2. Dpto de Química Orgánica, Facultad de Ciencias, Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, Zaragoza, Spain;3. Dpto de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Facultad de Ciencias, CSIC—Universidad de Zaragoza, Zaragoza, Spain |
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| Abstract: | A straightforward synthesis of mesogenic pyrazoles starting from benzaldehydes by a combination of efficient Henry and Michael reactions led to novel supramolecular liquid crystals. The mesogens are fluorescent 3,5‐dimethyl‐4‐(di or trialkoxyphenyl)pyrazoles and, in spite of the tapered shape of these molecules and their structural simplicity (only one phenyl ring), columnar liquid‐crystal phases were formed that are stable at room temperature. The self‐assembled structure was studied by XRD and the columnar cross section contains two molecules on average with an antiparallel arrangement of pyrazoles interacting through hydrogen bonds. In contrast, the single‐crystal structure of a trimethoxy analog did not show hydrogen‐bonded pyrazoles but chains of head‐to‐tail arranged molecules. |
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| Keywords: | columnar liquid crystals pyrazoles self-assembly X-ray diffraction |
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