Convenient solvatochromic probes for the determination of solvent properties: β-carotene and 2-chloro-7-nitro-9H-fluorene

• Autor(a) principal: Seoud,Omar A. El
• Data de Publicação: 2013
• Outros Autores: Pires,Paulo A. R., Loffredo,Carina, Imran,Muhammad, Pulcini,Paolo D., Corrêa,Michelle F., Mustafa,Rizwana
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532013000700001
• topic: solvatochromism; solvent dipolarity/polarizability; solvent dipolarity; solvent polarizability; β-carotene

Solvent dipolarity/polarizability (SDP) has been previously calculated from the UV-Vis spectra of 2-(N,N-dimethylamino)-7-nitro-9H-fluorene and 2-fluoro-7-nitro-9H- fluorene. Based on theoretical calculations (23 solvents) and experimental data (56 solvents), it is shown that 2-chloro-7-nitro-9H-fluorene (commercially available) can be conveniently employed for the calculation of this property, instead of its 2-fluoro-7-nitro counterpart. The splitting of SDP into its components (solvent dipolarity (SD) and polarizability (SP)) requires the use of a synthetic polyene compound whose synthesis is laborious, involving 15 steps. Our research group has recently shown that the natural dye β-carotene can be conveniently employed for the determination of SP, allowing the calculation of SD. Using these solvatochromic probes, SDP, SP and SD for a series of 1-bromoalkanes were calculated. For several homologous series, the dependence of solvent SDP (SD and SP for one series) on the number of carbon atoms in the 1-alkyl- or acyl-group was calculated and discussed.