Monoclinic to two-dimensional hexagonal transformation in hexacatenar molecules with a 1,2,3-triazole-based conjugated rod: morphology-dependent thermochromic behavior

Abstract

Novel hexacatenar molecules based on a 1,2,3-triazole-extended aromatic rod self-assemble into crystalline monoclinic and liquid crystalline hexagonal columnar structures depending on temperature. The phase transition may involve a conformational change from an anisotropic transoid to a half-disk cisoid conformer upon melting. In a hexacatenar molecule with sixfold octyl chains, the crystal-to-LC transition accompanies a photoluminescence color change from sky blue to dark blue, which is attributed to the formation of higher-order aggregates in the crystalline state.