Stilbazolium dyes

Strehmel B, Seifert H, Rettig W (1997) Photophysical properties of fluorescence probes. 2. A model of multiple fluorescence for stilbazolium dyes studied by global analysis and quantum chemical calculations. J Phys Chem B 101(12) 2232-2243... 

Sczepan M, Rettig W, Tolmachev AI, Kurdyukov VV (2001) The role of internal twisting in the photophysics of stilbazolium dyes. Phys Chem Chem Phys 3 3555-3561... 

Closely related to cyanine dyes are stilbazolium salts that are based on the styryl scaffold. Stilbazolium dyes are a class of fluorescent, lipophilic cations that have been used as mitochondrial labeling agents and membrane voltage-sensitive... 

In the family of stilbazolium dyes DASPMI, DPS etc., a similar three-state mechanism is active leading in this case to single-bond twisted TICT species with a high intrinsic nonradiative rate [108,109] probably connected with the ionic nature of the dyes (charge shift, see Sect. 4.5). This results in similar lifetime maxima as a function of temperature as for DCS but sizeably shifted to lower temperatures with respect to DCS [96]. 

Homopolymers and copolymers made from 3-vinylpyridinium salts form compact coils in solution media" while different isomers of dimethylamino-stilbazolium dyes exhibit different emitting states with a temperature dependent population." Using fluorescence depolarisation the relaxation time of poly-(styrene) chains has been found to decrease with expansion of the chain coils." " ... 

Measurements of surfactant concentrations on travelling capillary waves is complicated by the rapid decay rate of these waves, necessitating measurements close to the source of wave generation. To avoid this complication, we utilized a field of standing capillary waves. The wave tank was a circular (6.99 cm, inner diameter) glass vessel. The inner wall was coated with paraffin to avoid loss of the surfactant to the tank side walls. Triply distilled water was used as the substrate. The tank was overflowed to clean the surface prior to spreading the insoluble hemicyanine surfactant mono-layer at a surface concentration of 0.288 pg cm"2. Hemicyanine, 4-[4-(dimethylamino)styrl]-l-docosyl-pyridinium bromide, is a stilbazolium dye molecule to which is attached on one end a saturated twenty two car-... 

Hyperpolarizability of Centrosymmetric Langmuir-Blodgett Films of Stilbazolium Dyes", Thin Sol. Films, I6O, 209-215. 

Fig. 39. Stilbazolium dye with a tetrakis(pyrazolonato)dysprosate(III) complex as the counter ion (Wang et al.,...

Fig. 17 Chemical structure of the styryl dye (dibutylamino) stilbazolium butylsulfonate...

For merocyanine dye 4 —hydroxy—1 —methyl stilbazolium betain, following resonance structures are possible ... 

The desire to increase P values above those of molecules used in the earliest materials has led to the exploration of organic compounds as the active components of second order NLO devices. Considerable effort has been expended in the synthesis and analysis of candidate molecules, which are largely donor-acceptor substituted conjugated n systems. (2) Examples of compound classes whose members display large nonresonant P include azo dyes, stilbenes, polyenes, merocyanines, stilbazolium salts, and quinoid... 

Wostyn et al. [61] have reported the molecular nonlinear optical polarizability of lanthanate complexes containing stilbazolium ions. Their experimental results indicate that the hyperpolarizability is independent of the nature of the lanthanide, though the complex anion size is a function of the size of the ligand on the lanthanide cation. Andreu et al. [55] have synthesized a new chiral cyanine dye, 4 -[2-(methoxymethyl)pyrrolidinyl]-l-methylstilbazolium iodide (MPMS + I). They have reported that MPMS +1 exhibits phase-matched SHG with the efficiency of up to 80 times that of urea. 

ZWITTERIONIC DYES BASED ON PYRIDINIUM OR STILBAZOLIUM RING... 

The fluorescence properties of DCM, 4-cyanomethylene-2-methyl-6-p-dimethyl aminostyryl-4H pyran, show that there is thermal equilibrium between the cis- and trans-isomers. There is no observable aggregation of this dye except in liquid membranes. Polarized absorption and emission spectra of stilbazolium merocyanines and the properties of pyrylium and thiopyrylium high efficiency laser dyes are topics covered other related publications. 

Figure 1 Neutral and charge-separated resonance structures of two vinylogue merocyanine dyes (Ml, M2) and a conjugated betaine dye (stilbazolium betaine) (M3).

Our group has shown that the extremely strong negative solvatochromism of the chromophore stilbazolium betaine dye (11), about 6500 cm, is not a result of a change in the non-specific effect of the solvent but rather of change in acidity. This was confirmed by a study of the solvatochromic effect of a derivative of (11), o,o -di-tert-butylstilbazolium betaine dye (DTBSB) (12) in the same series of solvents. In this compound, the basic site in the betaine dye (its oxygen atom) is protected on both sides by bulky tert-butyl groups the specific effect of the solvent is hindered and the compound exhibits only a small solvatochromic effect that can be ascribed to non-specific solvent effects. ... 

By analyzing the ELD spectra of 2- and 4-[4-(dimethylamino)styryl]-l-ethylpyridinium cations on saponite suspended in DMF (Fig. 20), the tilt and roll angles of the dye were found to be controlled by the amount of the intercalated dye as well as the molecular structure (the position of cationic site within the dye) (103). The adsorption models of 4-[4-(dimethylamino)styryl]-l-ethylpyridinium cations on solid saponite are shown in Figure 21. Depending on the coverage, the orientation of 4-[4-(dimethylamino)styryl]-l-ethylpyridinium varied, as shown in Figure 21. The important role of the orientation of the stilbazolium cations will be discussed in a subsequent section. 

The acid parameter, S A, is based first on the relation between the observed frequencies, measured in nonacidic solvents, of the stilbazolium betaine dye 7 (TBSB R=H) and the 0,0 -di-t-butyl derivative (DTBSB R = t-butyl) represented by Equation 4.8. 

Hard (protonic) acidity (partial correlation of log T, (as preceding) vs. H Comparison of solvatochromism of an unhindered with a sterically hindered stilbazolium betaine dye. 

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