Absorption and Luminescence Properties of Bis-thiacarbocyanine in the Presence of Cucurbit[7,8]urils in Water

The effect of cucurbit[7,8]urils on the absorption and luminescent properties of bis-thiacarbocyanine (bis-TCC) based on 3,3'-dimethylthiacarbocyanine (TCC) perchlorate in water was studied. The existence of two forms of bis-TCC that absorb in the long-wavelength and short-wavelength ranges was established. The properties of the form absorbing in the long-wavelength region are similar to those of the TCC monomer (monomer form), whereas the form absorbing in the short-wavelength region exhibits the properties of the non-fluorescent TCC dimer (dimer form). The effect of cucurbit[7,8]urils was manifested as shifts of the absorption and fluorescence maxima, increase in the fluorescence intensity of both the monomer and the dimer forms, and the presence of thermally activated delayed fluorescence of the dimer form in deoxygenated solutions at room temperature. The results derived from spectral and luminescent measurements indicate the ability of bis-TCC to form complexes with cucurbit[7,8]urils.