Determination of Solute-Solute and Solute-Solvent Interaction of Pyrimidine-5-Carbonitrile in Aqueous DMSO at 298.15 K

Introduction: In this reported work, we have used 80 % aqueous dimethyl sulphoxide (DMSO) for density and viscosity measurement of pyrimidine-5-carbonitrile at 298.15 K. The obtained experimental results show that as concentration increases density and viscosity increases. From the results of density and viscosity, we have found apparent molar volume, limiting apparent molar volume, semi-empirical parameters, Falkenhagen coefficients and Jones Dole coefficients. Methods: The apparent molar volume and limiting apparent molar volume having negative values indicated electostrictive solvation of ions and weak or absence of ion solvent interactions, respectively. Results & Discussion: Falkenhagen coefficients are independent of concentration and possess positive values that shows strong solute-solute interactions. Jones-Dole coefficient with negative value shows weak solute-solvent interactions. The strong solute-solute interactions were present in A-1 as compared to A-2 compound because of the high electronegativity of oxygen atom. These parameters provides information about the type of the molecular interactions such as solute-solute, solute-solvent and solvent-solvent. Conclusion: We have reported density and viscosity study of 4-amino-2-hydroxy-6- phenylpyrimidine-5-carbonitrile and 4-amino-2-mercapto-6-phenylpyrimidine-5-carbonitrile in 80 % aqueous DMSO solution at 298.15 K. A stronger molecular association is observed in A-2 than A-1 shown by negative values of Øv.