The partial molar volumes of hydrated proton and electron determined with time-resolved photoacoustic

Photoinduced charge-transfer reactions in solution produce the formation or destruction of ionic species. Therefore, important structural rearrangements in the solutes and their solvent spheres can be expected, with a net (positive or negative) reaction volume change, $\delta$V$_R$, which in turn represents the difference between the individual partial molar volume, V$^o$, of the products and reactants. The partial molar volume is an important thermodynamic magnitude used in solution chemistry. In this presentation, the $\delta$V$_R$ information obtained with time-resolved photoacoustics (TRP) for a couple of photoinduced charge-transfer processes was used to estimate the V$^o$ of fundamental ionic species in aqueous solutions, such as the hydrated proton and electron

Probing second-sphere hydrogen-bonding interactions in metal complexes with time-resolved photoacoustic

Depending on the Lewis acid-base properties of the ligand moiety and the surrounding molecules, some coordination metal complexes can interact with the solvent molecules through second-sphere donor-acceptor (SSDA) interactions. In aqueous media, hydrogen bonding governs the solute-solvent interactions. In this report, the enthalpy content, $\delta$H$_{\rm MLCT}$, and the structural volume change, $\delta$V$_{\rm MLCT}$, associated with the formation and decay of the metal-to-ligand charge-transfer triplet state ($^3$MLCT) of ruthenium (II) bipyridine cyano complexes were determined using time-resolved photoacoustics (TRP), in water, water pools of reverse micelles, and in the presence of polyammonium macrocycle [32]ane-[N$_8$H$_8$]$^{8+}$, for the formation of supercomplexes. The results are explained as function of the structure and properties of the hydrogen-bonding interactions between the metal complexes and the surrounding molecules