Supramolecular Columnar Liquid Crystals with Tapered‐Shape Simple Pyrazoles Obtained by Efficient Henry/Michael Reactions. Issue 14 (18th February 2016)

• Record Type: Journal Article
• Authors: Blanco, Hugo; Iguarbe, Verónica; Barberá, Joaquín; Serrano, José Luis; Elduque, Anabel; Giménez, Raquel
• Is Part Of: Chemistry. Volume 22:Issue 14(2016)
• Page Start: 4924
• Page End: 4930
• Publication Date: 2016-02-18
• Subjects: columnar -- liquid crystals -- pyrazoles -- self-assembly -- X-ray diffraction; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201504779
• Languages: English
• ISSNs: 0947-6539

Abstract

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. Abstract : Tapered liquid crystals : A straightforward synthesis of pyrazoles leads to novel supramolecular synthons able to self‐assemble in soft columnar organizations.