NUCLEOTIDES ENHANCE THE FLUORESCENCE OF P-N,N-DIMETHYLAMINOSTYRYL)-N-VINYLBENZYLPYRIDINIUM CHLORIDE

The newly synthesized p-N,N-dimethylaminostyryl)-N-vinylbenzylpyridini um chloride (1) displays strong solvatochromic behavior resulting from a large increase of similar to 18 D in its dipole moment upon excitat ion. This indicates that its excited state has considerable charge tra nsfer character, suggesting that it may be subject to solute-induced f luorescence changes. The fluorescence quantum yield of 1 is enhanced d ramatically (12-fold) in the presence of a buffered aqueous solution o f cAMP, a purine nucleotide. in contrast, the pyrimidine nucleotides, CMP and UMP, have virtually no effect on the fluorescence of 1, cGMP i nduced an increase in the quantum yield of 1 similar to that induced b y cAMP, whereas other purine nucleotides (AMP, ADP and ATP) and adenos ine induced changes of somewhat lesser magnitude. Association constant s for 1 with these analytes ranged from 13.8 M-1 for cAMP to 0.15 M-1 for adenine. We conclude that the changes in fluorescence of I in the presence of nucleotides require the presence of a purine base, and are enhanced by ribose and phosphate moieties. The environmentally sensit ive fluorescence of 1 suggests that such compounds may be useful as ch emosensors for purine nucleotides. (C) 1998 Elsevier Science S.A. All rights reserved.