Study of the liquid crystalline phases of benzopurpurin in water

Structural Characteristics of the Chromonic Mesophases of C.I. Direct Blue 67

“…The diffuse maxima at the wide-angle scattering correspond to spacing d of 3.4 Å for all the LLC phases, calculated from where λ is the X-ray wavelength (1.542 Å for Cu Kα) and 2θ is the diffraction angle. The spacing of 3.4 Å is a characteristic diffraction of a columnar phase, indicating the stacking repeat distance of the aromatic dye molecules along the column. ,− 6a, This value was independent of the dye concentration within the range of the LLC phases. Even at a c w = 5 ( c w = concentration in wt %) dye solution, which is an isotropic liquid at room temperature, the XRD result still indicated the presence of this diffraction, although the intensity and sharpness decreased (Figure c).…”

“…The N phase possesses only an orientational order similar to that of the thermotropic N phase, whereas the M phase has an additional positional order of a hexagonal array. Following their discovery, analogues of LLC phases have also been found in xanthones used as anti-allergic drugs, azo dyes, cyanine dyes, guanosine derivatives, palladium organyls, and perylenes. , The literature and reports on chromonic LLCs are, however, still very limited. There are no clear explanations about the relationship between the molecular structure and chromonic LLC properties yet.…”

“…Many dichroic dyes with planar aromatic moieties having hydrophilic or ionic peripheral units exist but show no LLC properties. For example, Congo Red, which has a molecular structure similar to that of benzopurpurine except for the absence of two methyl groups and is an example of a chromonic LLC compound, loses the chromonic LLC properties 6b…”