NON-RADIATIVE ENERGY TRANSFER FROM Sm(III) COMPLEX ON CYANINE DYE Cy5

Abstract

The optimal conditions for the formation of new chelate Sm(III) with oxyquinoline carboxylic acid derivative (L) and spectral-luminescent characteristics (the maximum wavelength of luminescence, luminescence excitation and lifetime) were determinated. The quenching effect on the luminescence Sm(III)–L complex by cyanine dye Cy5 (fluorescent label of proteins and other biological molecules) was detected. The quenching of chelate complex due to Forster resonance energy transfer of electronic excitation (FRET) from the donor (Sm(III)–L) to the acceptor (Cy5). The intensity of the luminescence of the dye Cy5 in the presence of Sm(III)–L increased in 6 times.The values of the Forster radius (R0 (Sm-L) = 41 A) and the overlap integral of the luminescence energy of the donor with the absorption spectrum of the acceptor (JSm–L= 1.87×1012, M-1cm- 1nm4) calculated from the distribution of the quantum luminescence intensity of the donor, the spectrum and the molar absorption coefficient of the acceptor dye Cy5 possible to characterize as an efficient quencher of luminescence of Sm(III) ions. Sm(III)–L chelate complex is proposed as FRET-donor at first.