Structure and electronic absorption spectra of cyanine dyes – derivatives of tetrazolo- and triazoloisoindole

The electronic structure and absorption spectra of cyanine dyes – tetrazoloisoindole derivatives and triazoloisoindole were calculated. It was shown that these dyes, in terms of their electronic structure, are trimethine cyanine, although formally they are monomethine cyanine. The electron donation of the tetrazoloisoindole and triazoloisoindole residues was determined on the Ilchenko scale, which allows them to quantitatively quantify their Bruker basicity in comparison with the most known heterocyclic end groups of cyanine dyes.