Morphology-dependent luminescent behavior of hexacatenar Luminogens based on naphthalenyl and 1,2,3-triazolyl groups

Abstract The columnar assemblies and thermochromic properties of a hexacatenar molecule consisting of naphthalenyl and 1,2,3-triazolyl units were evaluated. The molecule formed 3D monoclinic crystalline (Cry mono ) and hexagonal columnar LC (Col hex ) phases as a function of temperature. Photoluminescence (PL) study revealed a noticeable change in the emission color at the Cry mono -to-Col hex transition. The aromatic cores in the Cry mono phases were stacked in an edge-to-face geometry and thereby exhibited a monomeric emission in the ultra-violet (UV) region. In contrast, a bluish excimer emission was observed for the Col hex phase with face-to-face stacking. Consequently, the fluorescent molecule exhibited different assembly features as a function of temperature, giving rise to distinct thermochromic phenomenon.