Studies of the binding interactions of dicationic styrylimidazo[1,2-a]pyridinium dyes with duplex and quadruplex DNA.

The dicationic styrylimidazo[1,2-a]pyridinium dyes were synthesized and characterized using 1 H NMR, 13 C NMR, mass spectral techniques and elemental analysis. In addition, their photophysical and DNA-binding properties were investigated. The dyes absorb in the UV region with maxima at 342–358 nm, and the emission spectra of these derivatives show a maximum at 409–475 nm with moderate Stokes shift. It was shown with spectrophotometric, spectrofluorimetric and viscometric titrations as well as with Circular dichroism spectroscopic analysis that the dicationic styrylimidazo[1,2-a]pyridinium dyes associate as groove binders with double-stranded DNA with binding constants in the range of 10 5 –10 6 M −1 . Preliminary experiments revealed that these ligands also bind with reasonable affinity to telomeric quadruplex DNA. [ABSTRACT FROM AUTHOR]