| Abstract: | Novel Dimethinmerocyanine Dyes Performing J-Aggregation in Highly Diluted Solution A series of various novel long-chain alkyl-dimethinmerocyanine dyes containing sulfonate groups is obtained in high yield by modified condensation reactions of sulfoalkyl- or sulfophenylsubstituted methylene ketones. The dyes exhibit intense, red-shifted absorption bands (? up to 263 000) due to J-aggregation in DMSO/H2O mixtures without addition of salt even at dye concentrations of 5 · 10?8M. The influence of dye structure and medium on the aggregation tendency is investigated. Besides it is found that exchange of the cationic counterions does not affect J-aggregation. |
