Binding of dansylamide † derivatives to nucleotides and nucleic acids 1
作者:Xuemei Wang、Hans-Jörg Schneider
DOI:10.1039/a801609g
日期:——
Dansylamideâ has been modified by the introduction of several side chains into the sulfonamide substituent. Compounds with no, or with only one positive charge at the side chains were found not to be useful for association studies with nucleotides or nucleic acids. Relatively high binding constants with moderate base selectivities have been observed with a ligand obtained from dansyl chloride and N,Nâ²-bis(3-aminopropyl)piperazine, which contains two dansyl units and two permanently charged peralkylammonium centers. Interactions of this ligand with double-stranded nucleic acids show a biphasic binding, the first at base pair concentrations below 10â7 M being only detectable by a decrease of fluorescence intensity. The second phase is characterized by increased fluorescence and by wavelength changes similar to effects observed in lipophilic solvents and by affinities of up to 5Â ÃÂ 105 M. At higher concentrations bathochromic shifts and extinction changes in UV spectra of the dye suggest an intercalation mechanism, in line with preliminary circular dichroism studies.
Searching for New Luminescent Sensors: Synthesis and Photophysical Properties of a Tripodal Ligand Incorporating the Dansyl Chromophore and of Its Metal Complexes
The new tripodal ligand 1 containing the dansyl chromophore has been synthesized and characterized. The intense luminescence characteristic of the chromophore is maintained in the ligand structure, showing that no intramolecular interactions are present. This ligand has been shown to complex in acetonitrile/water solutions only with Cu2+, Co2+, Zn2+, and Cd2+ ions, with concomitant pronounced changes