Blue light-emitting Quinoline armed Thiacalix [4]arene 3D-scaffold: A systematic platform to construct fluorescent liquid crystals with bio-imaging applications

Herein, cone-shaped thiacalix [4]arene appended quinoline-based substitution are designed, synthesized, and well characterized. The introduction of the terminal substituted alkoxy side chain at peripheries has created usual properties on these supramolecular thiacalixarene scaffolds. The thiacalixarene rigid core bearing bi-substituted quinoline functionalized arms with branched tails display a lower tempera-ture mesogenic property. The lower chain substituted supramolecules exhibit columnar hexagonal phase (Colh) while higher chain substituted compounds bearing smectic and nematic phase. Thus, in the class of cone-shaped supramolecules, the type and position of the peripheral side alkoxy group affect phase transition temperature including self-organization of the molecules, which is in disparity with traditional disc-shaped mesogens. The structure-property relationship is also discussed in this study to understand the effect of the polar alkyl chain on the exhibition of mesomorphic properties. These materials showed blue fluorescence in solution and a solid thin film state under a long UV region. The introductions of quinoline substituted arms on the lower rim of thiacalix core enhance the interactions between the cores and heterocyclic substitute and further comfort in the diminution of their clearing temperature and fur-ther enhance the mesophase transition range width. Further, these fluorescent quinoline-linked mesogens are used to stain model organism nematodes with a solution and aggregation state. The structural and conformation characterization of thiacalixarene-linked quinoline materials has been attained by different techniques like FT-IR, H-1 NMR, C-13 NMR, and MALDI-TOF. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study designed and synthesized cone-shaped thiacalixarene appended quinoline-based substitution compounds, and discussed the relationship between their properties and phase transition temperatures with peripheral alkoxy side chains. These materials exhibit columnar hexagonal phase at lower temperatures and smectic and nematic phases at higher temperatures, showing blue fluorescence in solid state.