Luminescence spectroscopic studies of trimethinecyanines substituted in polymethine chain with nucleic acids and proteins

Abstract

The series of symmetrical β-substituted and α,γ-substituted trimethinecyanine dyes were studied for their absorption and fluorescent characteristics in unbound state and in the presence of nucleic acids and proteins. It was shown that β-substituted and α,γ-bridged trimethinecyanines containing extended heterocyclic systems or N-phenyl as well as N-cyclohexyl substituents demonstrate increased affinity to proteins. At the same time the presence of both N-phenyl and N-cyclohexyl substituents leads to the decrease of the dye fluorescence intensity in complexes with nucleic acids. For trimethinecyanines similarly to unsymmetrical monomethines the presence of N-ω-hydroxy alkyl substituents results in the increase of fluorescence intensity of dye–DNA complex and the emission decrease of dye–RNA complex.