Synthesis and characterisation of a monotropic dendritic liquid crystalline aziridine monomer

Abstract

We synthesised a novel mesogenic dendritic aziridine, 2-(aziridin-1-yl)ethyl 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy)]benzoate (compound 2), by the esterification method with N,N′-dicyclohexylcarbodiimide. A crystalline compound was obtained with a melting point of 65°C and a monotropic columnar liquid crystalline (LC) phase on cooling. Preliminary polymerisation tests were performed in the presence of several initiators and conditions, and showed that in some cases cleavage of the benzyl ether linkage happened, while in some others polymerisation did not occur at all. Finally, we could polymerise compound 2 to some extent in deuterated tetrachloroethane in the presence of 1 mol% BF₃ · EtNH₂ at 125°C, as shown by ¹H NMR spectrum and polarised optical microscopic (POM) observation. Therefore, compound 2 could become a mesogenic precursor for the preparation of columnar polyamines.

Keywords:

• aziridine
• dendron
• polymerisation
• columnar phase