Computational and Spectral Means for Characterizing the Intermolecular Interactions in Solutions and for Estimating Excited State Dipole Moment of Solute

Abstract

The results obtained both in quantum chemical computation and in solvatochromic study of pyridinium di-carbethoxy methylid (PCCM) are correlated in order to estimate the electric dipole moment in the excited state of this molecule. This estimation is made by a variational method in the hypothesis that the molecular polarizability does not change in time of the absorption process. Ternary solutions of PCCM in protic binary solvents are used here, both establishing the contribution of each type of interaction to the spectral shift and to characterize the composition of the first solvation shell of PCCM. Results are compared with those obtained before for other binary solvents. The difference between the interaction energies in molecular pairs of PCCM-active solvent and PCCM-less active solvent was also estimated based on the cell statistical model of the ternary solutions.

Solvatochromic Study of Two Carbanion Monosubstituted 4-Tolyl-1,2,4-triazol-1-ium Phenacylids in Binary Hydroxyl Solvent Mixtures

“…The values from Table 6 show weak differences between the formation energies of hydrogen bonds between TTPY/TTNPY and the hydroxylic components of the solution [ 11 , 17 , 25 ]. Similar results (of the same order of magnitude) were obtained for the binary hydroxylic solvent mixtures water + ethanol and water + methanol and different probes in previous studies [ 15 , 17 , 22 , 38 ].…”

“…As relation (1) suggests, the sign plus of the correlation coefficients reflects a spectral shift to high wavenumbers (blue shift) in the electronic spectra. All coefficients are positive, showing a hypsochromic effect both of universal interactions (described by the π *, the polarity/polarizability parameter of the solvent) and of the specific interactions (described by the solvent parameters α and β ) [ 21 , 22 , 23 ]. This tendency has been observed in other binary hydroxylic solvent mixture solutions of some cycloimmonium ylids [ 22 , 38 ].…”

“…Some correlations [ 21 , 22 , 23 ] between the wavenumber in the maximum of the electronic absorption band and the solvent parameters, such as the hydrogen bond donor (HBD, noted by α ), hydrogen bond acceptor (HBA, noted by β ), and polarity/dipolarity number ( ), known as KAT parameters, were established: …”

Optimized Synthesis of New N-Mustards Based on 2-Mercaptobenzoxazole Derivatives with Antitumor Activity

“…The polar surface area (PSA) [ 47 , 48 , 49 , 50 , 51 ] defined as the sum of the polar atoms’ surfaces in a molecule is a useful parameter for prediction of drug transport properties. The values of PSA are between 28.490 and 29.781 Å 2 , these molecules being able to cross both the cell membranes and the blood-brain barrier.…”

“…The log P [ 47 , 48 , 49 , 50 , 51 ] value is a measure of lipophilicity or hydrophobicity. The chemical structures of the studied molecules are hydrophobic because the values of logP are positive.…”