Self-assembly of thiacyanine dyes in water for the synthesis of active hybrid nanofibres

Abstract

Water-soluble self-assembled nanostructures were synthesised by simple counter ion exchange of thiacyanine dyes which helps in the formation of nematic (N) and hexagonal (M) chromonic liquid-crystalline (CLCs) phases. Conjugated double bonds as central spacers connected between two benzothiazole segments affect water solubility and liquid crystal formation. Aggregationdependent properties characterised by ultraviolet-visible, fluorescence and 1 H nuclear magnetic resonance spectroscopy. Sol-gel reaction of dye aggregates with silica species furnishes entangled nanotubular fibres with constant diameter and their length in excess of micrometres, having templates of pore sizes below the mesoporous range. The π-π stacked chromonic aggregate dyes are also of importance in shape selective catalysis, adsorption, desorption micro-patterned materials, and provide a significant step towards biosensor medical applications because of their water-soluble nature.ARTICLE HISTORY

Theoretical Models, Preparation, Characterization and Applications of Cyanine J‐Aggregates: A Minireview

“…In a study by Shanker et al., [62] the formation of CJA with the same structure but with different polymethine lengths was carried out through counter ion exchange. The cyanines were ensembled into a silica nanofiber.…”

“…1 H‐ and 13 C‐NMR spectroscopy are commonly used for characterization of new cyanine syntheses. [ 62 , 70 ] The phase of the crystalline CJA can also be observed by NMR and XRD as well as the liquid crystal structure of the CJA. [70] Recently, multidimensional NMR methods such as diffusion ordered spectroscopy (DOSY) have been utilized to characterize CJA in their solution state.…”

Chromonic self-assemblies in a series of dialkyl-thiacarbocyanine dyes and generalization of a facile route for the synthesis of fluorescent nanostructured silica fibers

“…As we demonstrated in previous reports, [15,16,36] dye aggregates can serve as templates for the synthesis of mesoporous solids. We used cooperative self-assembly of the TCC series of compounds to produce silica materials aiming at demonstrating the generality of such a synthesis approach.…”

“…Previously, we reported for the first time chromonic liquid crystals formed by different cationic dyes. [15][16][17] Cyanine dyes were found to serve as templates for the preparation of mesoporous silica fibers. Evidence suggests that the anionic oligomeric silica species are bound to the cationic surface of the cyanine aggregates partially neutralizing the interaggregate long-range repulsions, causing chromonic-silicate fibers to precipitate.…”

Self-assembly of organic dyes in supramolecular aggregates

“…[9][10][11][12] But, it resurfaced recently with the advances in optoelectronics, photovoltaics and nanotechnology, where self-assembly is key to "bottom-up" approaches. 8,[13][14][15][16][17][18][19][20] The principal characteristic of aggregation is certainly its influence on the photophysical properties of a dye, and by consequence, theoretical models have been developed to describe the spectroscopic signature of molecular aggregates, as discussed later. [21][22][23][24] More importantly, aggregation allows for the most efficient way of transferring electronic excitation energy coherently across many sites, as exemplified by light-harvesting complexes found in the membranes of higher plants, photosynthetic bacteria and algae.…”