Solvatochromic analysis

P. A., Testa, B. Solvatochromic analysis of the retention mechanism of two novel stationary phases used for measuring lipophilicity by RP-HPLC./. Liquid Chromatogr. 1992, 35, 2133-2151. 

Stella, C., Galland, A., liu, X., Testa, B., Rudaz, S., Veuthey, J. L, Carrupt, P. A. Novel RPLC stationary phases for lipophilicity measurement solvatochromic analysis of retention mechanisms for neutral and basic compounds. /. Sep. Sci. 2005, 28, 2350-2362. 

I. 2-dichloroethane-water partition coefficients. A solvatochromic analysis,... 

Use of Solvatochromic Equations Solvatochromic analysis for log P calculations appears to be one of the more useful approach built using linear free energy relationship (LEER) described by the general Equation (5.6) [58] ... 

Pagliara, A., Caron, G., Lisa, G., Fan, W, Gaillard, R, Carrupt, P.-A., Testa, B. and Abraham, M.H. (1997a). Solvatochromic Analysis of di-n-butyl EtherAVater Partition Coefficients as Compared to Other Solvent Systems. J.Chem.Soc.Perkin Trans.2,2639-2643. 

Steyaert, G., lisa, G., Gaillard, P, Boss, G., Reymond, E, Girault, H.H., Carrupt, P.-A. and Testa, B. (1997). Intermolecular Forces Expressed in 1,2-Dichloroethane-Water Partition Coefficients. A Solvatochromic Analysis. J.Chem.Soc.Faraday Trans., 93,401-406. 

Vallat, R, Fan, W., El Tayar, N., Carrupt, P.-A. and Testa, B. (1992). Solvatochromic Analysis of the Retention Mechanism of TVo Novel Stationary Phases Used for Measuring Lipophilicity by RP-HPLC. J.Liquid Chromat., 15,2133-2151. 

Nucleophilic substitution reactions of dansyl chloride with anilines (entry 16)128 are reported in various protic solvents. Interestingly, the Px values are in parallel with the rates, which are dependent on the dielectric constant (e)49 of the solvent as can be seen from the data presented for each solvent in the order [e k2 (xlO4 M 1 s 1 at 30 °C for X = H) px], MeOH [32.66 107 0.67], EtOH [24.55 37.7 0.55], w-PrOH [20.45 8.71 0.50], 2-PrOH [19.92 5.33 0.41], n-BuOH [17.51 3.07 0.34], MeCN [35.94 13.7 0.72]. In the aprotic solvent MeCN, the rate is somewhat slow despite the largest s and Px values. Since the reactivity changes in parallel to the selectivity, the RSP is violated, and a stepwise mechanism through an intermediate can be excluded. Solvatochromic analysis also suggested that the reaction proceeds via an associative S 2 mechanism. 

Both absorption and emission electronic transitions are acceptably described by our scales, as shown by a recent study on the solvation of a series of probes containing an intramolecular hydrogen bond, so no further comment is made here other than the following even if one is only interested in evaluating the change in dipole moment upon electronic excitation via solvatochromic analysis, a multi-parameter analysis must be conducted in order to isolate the shifts corresponding to the pure dipolar effect of the solvent. ... 

These scales have also been widely used in the solvatochromic analysis of a variety of compounds. Worth special note here are the studies of Low et a/." on coumarins, Boens et on BODlPYs, Abelt et al on PRODAN derivatives and Spange et... 

A. de Juan, G. Fonrodona and E. Casassas, Solvent classification based on solvatochromic parameters a comparison with the Snyder approach. Trends Anal. Chem., 16(1) (1997) 52-62. T. Naes, The design of calibration in near infra-red reflectance analysis by clustering. J. Chemom., 1 (1987) 129-134. 

This solvatochromic solvent effect equation has been probably the most widely used one in the analysis of solvent effects40 and it has been applied to literally hundreds of processes in solution and for the correlation of all kinds of solvents effects39-43. 

As mentioned in Section 4, the analysis of rate data resulting from unimolecular reactions is considerably easier than the analysis of such data for bimolecular reactions, and the same is true for pseudounimolecular reactions. Kinetic probes currently used to study the micellar pseudophase showing first-order reaction kinetics are almost exclusively compounds undergoing hydrolysis reactions showing in fact pseudofirst-order kinetics. In these cases, water is the second reactant and it is therefore anticipated that these kinetic probes report at least the reduced water concentration (or better water activity in the micellar pseudophase. As for solvatochromic probes, the sensitivity to different aspects of the micellar pseudophase can be different for different hydrolytic probes and as a result, different probes may report different characteristics. Hence, as for solvatochromic probes, the use of a series of hydrolytic probes may provide additional insight. 

Solvatochromism Solvent polarity Analysis, sensors, monitoring of polymers and polymerisation... 

For example, dissolving the betaine (1.98) or another negative solvatochromic dye in PMM and spin coating the solution to give a film on a sensor tip provides a product suitable for the analysis, in visible absorption or transmission mode, of alcohols and ethers in gasoline. 

Transition moments, ioi> to the first excited state can be calculated from the integrated absorption of the linear electronic spectrum. This can be used to calculate -Af poi n the first term (defined here as yc) of the two-level model. The second term (Af p.oiAjioi m) from Equation (12) (defined here yn) involves Ajioi, which can be determined directly from solvatochromism( 19), or from a two-level analysis of a molecular EFISH measurement of p. 

There have been other phenomenological approaches to rationalize (or even predict) the experimentally observed solvent effect on the chemical shift. Many chemists use the Kamlet-Abbout-Taft (KAT) set of solvatochromic parameters it, a and 8 [31], KAT parameters can be used together with the multiple linear analysis to describe the variation in the chemical shift of the solute as the solvent is varied. An extensive study of this type was conducted by Witanowski et al. to interpret the solvent effects on the shielding of l4N in a large set of compounds (see ref. [32] and references cited therein). For a nitroso aliphatic and aromatic series, solvent-induced shielding was indeed found to depend on the polarity of the solvent. However, other experience with this model suggests the need for caution. 

The computational and experimental analysis of time dependent solvatochromic shift in fluorescence spectra of solutes is used by Ladanyi to achieve an accurate description of solvation dynamics, i.e., the rate of solvent reorganization in response to a perturbation in solute-solvent interaction. 

The Kamlet-Taft scheme [189, 203, 204] represents a LEER for the analysis of a solvent environment via solvatochromic effects. The Kamlet-Taft model is similar to the form of Eq. (10), but is simplified... 

A number of studies have attempted to characterize ionic liquids through their dielectric constant, and all have observed inconsistencies between the measured dielectric constant and the solvation properties of the liquid. Recent experiments making use of dielectric reflectance spectroscopy [214] indicate dielectric constants in the range of 10-15 for a series of imidazolium-based ILs, substantially lower than those for molecular solvents observed to possess comparable polarities as estimated by solvatochromism. Weingartner [215] has recently published a series of static dielectric constants obtained from dielectric reflectance spectroscopy, and compared them with those of common molecular liquids. The analysis includes comparison with the Kamlet-Taft ji parameter for the liquids from Eq. (11) we have prepared a plot of n versus dielectric constant in Fig. 6. The relationship between n and e for molecular liquids... 

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