1,4‐Diaryl and Schiff's base [1,2,3]‐triazole derivative liquid crystalline compounds

Abstract

Regioselective synthesis of [1,2,3]‐triazoles based on the ‘click‐reaction’, involving the Cu(I)‐catalysed 1,3‐dipolar cycloaddition of aryl azide to terminal arylacetylenes, was successfully employed in the preparation of two series of non‐linear mesogens, based on 1,4‐diaryl‐[1,2,3]‐triazole (Ia–e) and with Schiff's base units (IIa–c). Their mesophases were characterized by polarizing optical microscopy and differential scanning calorimetry. All final compounds exhibited preferentially the SmC phase. In addition, compounds of series I showed weak blue fluorescence in solution (λ_{max. em.} = 380–386 nm) with poor quantum yields and a Stokes shift of around 90 nm.

Acknowledgments

The authors thank Mrs Marly da Silveira Soldi (DSC measurements) and Prof. Dr Faruk Nome for free access to photophysical instruments, and the agencies: Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Brazil) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, Brazil) for the PhD scholarships. The authors also acknowledge FAPESC‐Brazil and Merck for funding.