The effect of solvents on the absorption and emission spectra of 1,4-bis(5-phenyl-2-oxazolyl)benzene (POPOP) laser dye has been studied in various solvents at 298 K. A bathochromic shift was observed in absorption and fluorescence spectra upon increase of solvent polarity, which indicates that this transition is π-π *. The ground and excited state dipole moments were calculated as 2.23 and 6.34 Debye, respectively. The dye solution in MeOH, n-heptane, and methyl isobutyl ketone gives laser emission in the blue region upon excitation by a 337.1 nm nitrogen pulse; the gain coefficient and emission cross section as well as normalized photostability have been determined. Excitation energy transfer from POPOP to rhodamine B and fluorescine was studied to improve the laser emission from these dyes. Such an energy transfer dye laser system (ETDL) obeys a long range columbic energy transfer mechanism with a critical transfer distance, R 0 , of 25 and 33Å and k q equal to 10.4 × 10 12 and 26.2 × 10 12 M −1 s −1 for the POPOP/RB and POPOP/fluorescine pair, respectively. The POPOP dye is highly photostable in polar protic and polar aprotic solvents, while it displays photodecomposition in chloromethane solvent via formation of a contact ion pair. The photochemical quantum yield and rate of photodecomposition depend on the electron affinity of solvent.

No abstract

No abstract

D-π-A dye composed of pyrene and thiophene units was synthesized and characterized using elemental, FT-IR, and mass analyses. The solvatochromic response was investigated in different solvents of various polarities. Additionally, the inclusion characteristic of the investigated dye was studied in different organized assemblies of three surfactants. The spectral changes suggested that the dye would be useful to study the critical micelle concentrations of the studied assemblies systems. Furthermore, the absorption and emission spectra are sensitive towards H + , Co 2+ , Ni 2+ , Cd 2+ , Pb 2+ , and Zn 2+ ions owing to acido-and metallo-chromic behaviors.These results suggest that the investigated dye would be potential candidate for polarity sensors, probe to characterize microenviromental polarity of the surfactants, and sensor for metal ions and H + proton.

D-π-A chalcone composed of pyrene and thiophene units was synthesized and characterized. The solvatochromic response was investigated in different solvents of various polarities. Additionally, the inclusion characteristic of the investigated dye was studied in different organized assemblies of three surfactants. The spectral changes suggested the chalcone would be useful to study the critical micelle concentrations of the studied assemblies systems. Furthermore, the absorption and emission spectra are sensitive towards H + , Co 2+ , Ni 2+ , Cd 2+ , Pb 2+ , and Zn 2+ owing to acido-and metallo-chromic behaviors. These results suggest that the investigated chalcone would be potential candidate for polarity sensors, probes to characterize microenviromental polarity of the surfactants, and sensors for metal ions and H + proton.