Solvent effects on chemical phenomena (rates; equilibria; spectroscopic transitions) are analyzed in terms of solvation free-energy relationships, including solvent (S) �acidity, SA�, �basicity, SB�, dipolarity, SD, and polarizability, SP. These properties are calculated from the spectra of solvatochromic probes. The probe required for the determination of SP is a polyene, ttbP9, whose synthesis involves 15 steps! Results of this probe are also required for the determination of SD. Based on DFT/B3LYP calculations for 23 solvents, and experimental data for 80 molecular solvents and ionic liquids, ILs, we show that the green, inexpensive dye beta-carotene can be conveniently employed instead of ttbP9. The natural dye has been employed, along with 2-(N,N-dimethylamino)-7-nitrofluorene in order to determine SD; the total number of solvents is 103. The dependence of both solvent properties on the number of carbon atoms in the solvent, aliphatic alcohols; 2-alkoxyethanols; carboxylic anhydrides and esters; ILs will be discussed. Acknowledgements     We thank FAPESP for financial support, and the following for research fellowships: Petrobr�s, C. Loffredo); CNPq, O. A. El Seoud; CNPq/ TWAS, M. Imran.

Beta-Carotene: A green, inexpensive, and convenient solvatochromic probe for the determination of solvent dipolarity and polarizability

245th National Meeting (2013)

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