Interaction of fluorescence probe possessing ICT behavior with DNA and as a potential tool for DNA determination

This paper investigates the interaction of a fluorescence probe, 4'-N, N-di methylamino-3-hydroxy-flavone (DMAHF), possessing intramolecular charge tra nsfer (ICT) behavior, with DNA. The fluorescence spectra, fluorescence anis otropy, and effect of experimental parameters on ICT emission have been stu died. In the phosphate buffer of pH 7.0, the fluorescence from ICT was almo st completely quenched. It enhanced dramaticaly in the presence of DNA. The enhancement effect is thought to involve in (1) the immersion of the DMAHF molecules in the hydrophobic region of the DNA double helix where the solv ation was inhibited effectively and (2) the restraint of the nonradiative t wisted ICT state with viscosity. The analytical potential for determining D NA using the enhancement of ICT fluorescence has been examined. (C) 1999 Ac ademic Press.