Maltose-based gelators having azobenzene as light-sensitive unit

Abstract

Three light-sensitive amphiphiles, based on azobenzene, have been synthesized as supramolecular gelators. A hydrophobic chain with an azobenzene group incorporated at different positions was click coupled to a maltose polar head by a copper(I)-catalysed azide–alkyne [3 + 2] cycloaddition. The liquid crystalline and gel properties of these azo-amphiphilic materials have been studied. Two of these azo-gelators containing maltose give rise to stable gels in water or in a mixture of water and DMSO at room temperature. The chiral supramolecular assemblies of these gelators have been characterised by NMR, electron microscopy and circular dichroism (CD). The light-response of azo-amphiphiles in supramolecular gels has been studied. Also azo-gels, which contained mixtures of the azo-amphiphilic compounds and a similar structural hydrogelator, have been investigated.