Solvent influence on some complexes realized by hydrogen bond

Solvent scales used to study the intermolecular interactions in binary solutions of two p-aryl-pyridazinium methylids

“…In Fig. 6, the dependence between the E max (kcal/mol) in the maximum of the ICT absorption band of the two studied pyridazinium ylids and the normalized E N T of E T (30) values is also linear. The parameters of the linear dependence (4) are listed in Table 5.…”

“…The electronic distribution indicates a high electrophilicity of the pyridazine cycle in HOMO orbital, explaining the direction of the intramolecular charge transfer by excitation (from the ylid carbanion towards the heterocycle. In LUMO orbital, the high electron density is located on the picryl substituent, explaining the ability of this substituent to participate in hydrogen bonds with proton of -OH groups from alcohols, diols or acid solvents [30][31][32].…”

“…This molecule shows an extremely solvatochromic character. The E T (30) parameter is defined by the position (in kcal mol À1 ) of the maximum of the first absorption intramolecular charge transfer (ICT) band for this dye. The dipole moment in the excited state of standard probe is much smaller that than in ground state resulting a strong hypsochromism when the solvent polarity increases.…”

“…All pyridazinium ylids have a visible absorption band due to an intramolecular charge transfer (ICT) from carbanion to heterocycle [30][31][32][33][34]. This band is extremely sensitive to the solvent nature.…”

Variational Method for Estimating the Dipole Moment in the Second Excited State of Fluorescein Molecule from its Electronic UV Absorption Spectra

“…Density Functional method of Spartan'14 program [39,40] was used to compute some theoretical properties of fluorescein. Spartan is a molecular modeling program using permittivity [41,42], respectively, are listed in Table 1, which also contains the Kamlet-Taft solvent parameters hydrogen bond donor (α ) and hydrogen bond acceptor (β) [43][44][45][46]. Ultraviolet electronic absorption spectra of fluorescein were recorded in 14 solvents at room temperature, with QE65000 UV-Vis Ocean-Optics spectrometer.…”