Volumetric Properties of the Nucleosides Adenosine, Cytidine, and Uridine in Aqueous Solution at T = (288.15 and 313.15) K and p = (10 to 100) MPa

Abstract

Speeds of sound have been measured for aqueous solutions of the nucleosides adenosine, cytidine, and uridine at the temperatures T = (288.15 and 313.15) K and at the pressures p = (10, 20, 40, 60, 80, and 100) MPa. Using the methods described in our previous work, the partial molar volumes at infinite dilution, $$V_{2}^{\text{o}}$$ , the partial molar isentropic compressions at infinite dilution, $$K_{S,2}^{\text{o}}$$ , and the partial molar isothermal compressions at infinite dilution, $$K_{T,2}^{\text{o}} \left\{ {K_{T,2}^{\text{o}} \, = \, - \left( {\partial V_{2}^{\text{o}} /\partial p)_{T} } \right)} \right\}$$ , for the nucleosides were derived from the speed of sound data at elevated pressures. The thermodynamic properties $$V_{2}^{\text{o}}$$ and $$K_{T,2}^{\text{o}}$$ were combined with those determined previously for T = 298.15 K to create 3D surfaces that display the pressure and temperature dependences of these properties. The purine nucleoside adenosine displays distinctly different trends in these properties from those of the pyrimidine nucleosides cytidine and uridine. A semi-empirical model was used to rationalize the $$K_{T,2}^{\text{o}}$$ results in terms of likely changes in hydration as a function of temperature and pressure.