Simulations ab initio et DFT des propriétés électroniques et thermodynamiques de deux isomères du dibromodinitrofluorescéine.

Abstract

In this thesis, we use ab initio and DFT methods to investigate the electronic and thermodynamic properties of 4,5-dibromo-2,7-dinitro-fluorescein (compound 1 or eosin B dye) and 2,7-dibromo-4, 5-dinitro-fluorescein (compound 2), as well as the influence of solvents onto their properties, by using the default method IEF-PCM of window’s version of Gaussian 09 W suit of program. We use the RHF and DFT (PBE1PBE, MPW1PW91, B3PW91 and B3LYP) approaches to calculate the properties of eosin B dye such as: structural and nonlinear optical parameters, energy bandgap (Egap), Zero-point vibrational energy (ZPVE), total electronic energy (Etot), Gibbs free energy(G), Enthalpy(H), molar heat capacity at constant volume (Cv) and Entropy(S) with cc-pVDZ basis set. We justify the choices of the methods used for eosin B dye and finally use them to investigate the properties of compound 2. At the end of this justification, we retain the RHF method and B3LYP level of approximation that we use to predict and analyze electronic and thermodynamic properties of compound 2 and look at the effect of solvation on both compounds. From our results, we observe that the effect of electron correlation and solvation have little or no effect on some of the properties of these compounds. The negative values of binding energy on the both compounds obtained from our results equally show that these compounds have potential applications in medicine, as well as in linear and nonlinear optical devices with their large values of electric parameters. The large values of βmol and μ of these compounds permit us to conclude that they have potential applications in the field of optoelectronic and medicine for the conception of antimalaria and coronavirus drugs.