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Current issue   Ukr. J. Phys. 2014, Vol. 59, N 3, p.226-232

    Paper

Closca V.1, Zelinschi C.B.2, Babusca D.1, Dorohoi D.O.1

1 Alexandru Ioan Cuza University, Faculty of Physics
(11, Carol I Blvd., Iasi RO-700506, Romania)
2 Vasile Adamachi College for Agricultural and Food Industry
(41, M. Sadoveanu All., Iasi, Romania)

Solvent Empirical Scales for Electronic Absorption Spectra

Section: Atoms and molecules
Original Author's Text: English

Abstract: Linear correlation between the Emax (kcal/mol) of the visible electronic absorption band of four pyridazinium ylids and the empirical polarities Z (kcal/mol) defined by Kosower are established, proving the intramolecular charge transfer nature of this band. The slopes of the lines are smaller for the carbanion monosubstituted ylids, compared with those of the carbanion disubstituted ylids. This fact emphasizes the prevalence of the dipolar interactions in ylid solutions.
The blue shifts recorded in the protic solvents suggest the hydrogen bond formation between the –OH of these solvents and the ylid carbanion. A linear dependence exists between the values of Emax (kcal/mol) recorded for two studied ylids.
This fact demonstrates that the solvents can be arranged on the empirical scale describing their action on similar chemical compounds, in which electronic transitions of the same nature take place.

Key words: electronic absorption spectra, ylids, 1-ethyl-4-carbomethoxy-pyridinium iodide.