Spectral, Acid−Base, and Laser Characteristics of 1,4-Bis[β-(2-quinolyl)vinyl]benzene (BQVB)

Abstract

The diolefinic dye BQVB is an efficient fluorescer with φ f values as high as 0.82 in n-heptane. The dye exhibits low values of the excited state lifetimes of ca. 0.4 ns. Both electronic absorption and fluorescence spectra are sensitive to medium acidity, and in acidic media a strong fluorescence is obtained at 500 nm. The laser activity of BQVB has been investigated. The dye solution in N,N-dimethylformamide (DMF) gives laser emission around 450 nm upon excitation by 337.1 nm nitrogen laser pulse. The excited state absorption S 2 r S 1 of BQVB has been measured using laser flash photolysis, and in DMF the S 2 r S 1 absorption occurs at ca. 762 nm. Energy transfer from BQVB to rhodamine 6G and to molecular oxygen has been studied. The quantum yields for the trans-cis photoisomerization (φ c ) of BQVB in different organic solvents are also reported.

Photophysical Parameters, Excitation Energy Transfer, and Photoreactivity of 1,4-Bis(5-phenyl-2-oxazolyl)benzene (POPOP) Laser Dye

“…There is also a good mirror image relationship between absorption and fluorescence spectra. These facts, together with high molar absorptivities (ε = 32500-56500 mol dm −3 cm −1 ) and high oscillator strength ( f = 0.57-1.02), are consistent with a strong π-π * transition with a small geometry change between electronic ground and excited states [41]. The fluorescence quantum yields φ f are slightly affected by solvent properties; the values of φ f in methyl isobutyl ketone (φ f = 0.68) and acetone (φ f = 0.69) are low due to the carbonyl group quenching the singlet excited state via enhancement of intersystem crossing (S 1 → T 1 ), while the high value of fluorescence quantum yield in ethylene glycol (φ f = 0.92) can be explained in term of a cage effect and the role of medium viscosity which decrease the stretching and twisting molecular motion in the excited state, thereby decreasing the nonradiative process [42].…”

Quantum chemical studies on structures and spectra of 2,5-distyrylpyrazine (DSP) laser dye

“…A similar behavior was observed experimentally for the quinolyl diolefinic analog. 3 The rotational potential constants V , V , and V 1 2 3 are all negative at y0.0134, y1.0039, and y0.0289 kcalrmol, respectively. V and V are very small 1 3 and the potential function is dominated by a large negative V term, leading to equivalent minima at 2 the cis and trans conformations at the expense of Ž .…”

“…8 8 tion ESA , solubility limitations, and acid᎐base properties. 3 In the present series of laser dyes it was realized that dyes containing pyrazinyl moieties are generally less efficient dyes compared with those containing the pyridyl ones. 9 The tendency to molecular aggregation also increases in pyrazinyl derivatives compared with pyridyl ones.…”

Synthesis, Spectral Characteristics and DFT Studies of the New Dye 2,7-diacetyl-9-((dimethylamino)methylene)-9H-fluorene (DMMF) in Different Solvents

“…Light intensity of irradiation wavelength was measured using ferrioxalate actinometry [19]. The photochemical quantum yields (φ c ) of DMMF were measured using a modified method that takes into account the decrease in absorbance at the excitation wavelength as photoirradiation proceeds [20].…”