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 H-1 NMR, C-13 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. (C) 2015 Elsevier Ltd. All rights reserved.