ABSORPTION AND LUMINESCENT PROPERTIES OF COVALENTLY LINKED BIS-THIACARBOCYANINES IN THE PRESNCE OF СUCURBIT[7,8]URILS IN WATER

Abstract

The effect of cucurbit[7,8]urils on absorption and luminescent properties of bis-thiacarbocyanine (bis-TCC) based on 3,3'-dimethylthiacarbocyanine perchlorate (TCC) has been studied in water. The existence of two forms of bis-TCC which absorb in the long-wavelength and short-wavelength regions of the spectrum has been established. The properties of the form absorbing in the long-wavelength region are similar to that of the monomer of TCC (monomeric form), whereas the form which absorbs in the short-wavelength region exhibits the properties of a non-fluorescent dimer of TCC (dimeric form). The influence of cucurbit[7,8]urils manifests itself in shifts of the band maxima in the absorption and fluorescence spectra as well as in increase in the fluorescence intensity of the monomeric and dimeric forms, and also in the presence of thermally activated delayed fluorescence of the dimeric form in deoxygenated solutions at room temperature. Results obtained from the spectral and luminescent properties indicate the ability of bis-TCC to form complexes with cucurbit[7,8]urils.