Journal of Physical Studies 6(2), 236–242 (2002) DOI: https://doi.org/10.30970/jps.06.236 SPECTRAL PROPERTIES OF SYMMETRICAL THREEMETHINE CYANINES WITH α-, γ-SUBSTITUTED POLYMETHINE CHAIN IN THE PRESENCE OF NUCLEIC ACIDS I. Valyukh{1}, A. Slobodyanyuk{1}, V. B. Kovalska{2}, A. Grangan{3}, Y. L. Slominskii{3}, S. M. Yarmoluk{2} {1}Physics Department of Kyiv T. Shevchenko National University, 6 Pr. Acad. Glushkova, Kyiv, UA–03147, Ukraine, {2}Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, 150 Acad. Zabolotnogo Str., Kyiv, UA–03143, Ukraine; e-mail: otava@carrier.kiev.ua {3}Institut of Organic Chemistry NASci of Ukraine, 5 Murmanska Str., Kyiv, UA–02094, Ukraine.

Spectral-luminescent properties of four symmetrical threemethine cyanine dyes with $α $-, $γ $-substituted polymethine bridge in a free state and in the presence of nucleic acids (NA) have been investigated. It has been shown that replacement of the ethilene bridge by the vinilene one in a polymethine chain of the threemethine cyanines influenced meaningfully the spectral properties of these dyes. The bands of aggregates in absorption spectra of the aqueous solutions of free dyes were observed. CPentE, CPentV and CpentE-OMe form high fluorescence complexes in the NA presence. These dyes can be used as luminescent probes for NA detection in homogeneous assays. The introduction of methoxy groups into the residue of the threecarbocyane with ethilene bridge does not make worse its properties as probe for NA detection. The presence of these groups in an analogue with the vinilene bridge has diminished the fluorescence intensity in the CPentE-OMe-NA complex. The obtained results for CpentE and CPentV indicate that these dyes are bound into the DNA groove.

PACS number(s): 87.15.-v, 87.64.-t

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