| Abstract
| - We report on the photophysical properties and laser action of five newly synthesized dipyrromethene·BF2complexes that are analogues of the laser dye PM567 dissolved in apolar, polar nonprotic, and polar proticsolvents, paying attention to the effect of the dye concentration. All of these dyes have a common chromophorecore and differ in the length of 8-(ω-acetoxy)polymethylene substituent. When pumped transversely at 534nm, laser efficiencies up to 59% were obtained, which were found to be nearly independent of the nature ofthe solvent and the length of the polymethylene chain. Good correlations between the photophysical propertiesin diluted solutions and the lasing characteristics in moderately concentrated solutions have been observed.The presence of the 8-substituent does not modify significantly the photophysics of the chromophore, if thepolymethylene chain has five or more methylene groups. Theoretical calculations were performed to rationalizethis behavior.
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