1 research outputs found
Chiral Supramolecular Gels with Lanthanide Ions: Correlation between Luminescence and Helical Pitch
We report the correlation
between the fluorescence intensity and the helical pitch of supramolecular
hydrogels with TbÂ(III) and EuÂ(III) as well as their inkjet printing
patterning as an application. The luminescent gels, which exhibited
three different emissions of red, green, and blue, could be prepared
without and with EuÂ(III) and TbÂ(III). The luminescence intensity of
supramolecular gels (gel-Tb and gel-Eu) composed of TbÂ(III) and EuÂ(III)
was ca. 3-fold larger than that of the sol (<b>1</b>+TbÂ(III)
or <b>1</b>+EuÂ(III)), which was attributed to large tilting
angles between molecules. By AFM observations, these gels showed well-defined
right-handed helical nanofibers formed by coordination bonds in which
the helical pitch lengths were strongly dependent on the concentrations
of lanthanide ions. In particular, the large luminescence intensity
of gel-Tb exhibited a smaller helical pitch length than that of gel-<b>1</b> due to relatively weak π–π stacking with
large tilting angles between molecules. The luminescence intensities
were enhanced linearly with increasing concentrations of lanthanide
ions. This is the first example of the correlation between the helical
pitch length and the luminescence intensity of supramolecular materials.
The coordination bonding in supramolecular hydrogels had a strong
influence on rheological properties. We also developed a water-compatible
inkjet printing system to generate luminescent supramolecular gels
on A4-sized paper. The images of a logo and the text were composed
of three different emissions and were well-printed on A4 sized paper
coated with gel-<b>1</b>