Abstract
The solvatochromic characteristics of flavone and 7-hydroxyflavone were investigated in neat and binary solvent mixtures. The spectral shifts of these solutes were correlated with the Kamlet and Taft parameters (α, β and π*) using linear solvation energy relationships. The multiparametric analysis indicates that both specific hydrogen bond donor ability and non-specific dipolar interactions of the solvents play an important role in absorption maxima of flavone in pure solvents. The hydrogen bond acceptor ability of the solvent was the main parameter affecting the absorption maxima of 7-hydroxyflavone. The simulated absorption spectra using a TD-DFT method were in good agreement with the experimental ones for both flavones. Index of preferential solvation was calculated as a function of solvent composition. Preferential solvation by ethanol was detected in cyclohexane-ethanol and acetonitrile-ethanol mixtures for flavone and in acetonitrile-ethanol mixtures for 7-hydroxyflavone. These results indicate that intermolecular hydrogen bonds between solute and solvent are responsible for the non-linear variation of the solvatochromic shifts on the mole fraction of ethanol in the analyzed binary mixtures.
Highlights
The study of solvent effects on the structure and spectroscopic behavior of a solute is essential for the development of solution chemistry [1,2,3,4,5]
An experimental and theoretical study on the solvatochromic effects of flavone (F) and 7-hydroxyflavone (7HF) is carried out in pure solvents as well as in binary mixture solvents using UV-vis spectroscopy and DFT methods in order to describe the solute-solvent interactions that these compounds present
The solvatochromic shifts observed in pure solvent were evaluated using linear solvation energy relationships (LSER) with the Kamlet and Taft parameters, and the electronic transitions were explained with the PCM/TD-DFT treatment
Summary
The study of solvent effects on the structure and spectroscopic behavior of a solute is essential for the development of solution chemistry [1,2,3,4,5]. The presence of specific and non-specific interaction between the solvent and the solute molecules are responsible for the change in the molecular geometry, electronic structure and dipolar moment of the solute. In these kinds of systems, the solute may induce a change in the composition of the solvents in the cybotactic region compared to that in the bulk leading to preferential solvation This situation commonly results from specific (hydrogen bonding) and non-specific (dielectric effects) interactions. An experimental and theoretical study on the solvatochromic effects of flavone (F) and 7-hydroxyflavone (7HF) is carried out in pure solvents as well as in binary mixture solvents using UV-vis spectroscopy and DFT methods in order to describe the solute-solvent interactions that these compounds present
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
