This grant in the Organic and Macromolecular Chemistry Program supports research by Prof. Ernest Grunwald, which aims at increasing chemical understanding of two important aspects of chemical structure and reactivity in solution: (1) the interionic structure of ion pairs, as analyzed by their electric dipole moments; and (2) hydrophobic interactions and solvent structure in solution, via spectroscopic studies of laser dyes. Both areas of research, though experimentally unrelated, are important for advancing understanding of dynamic chemical phenomena in ionic solutions. The ion-pair project is a continuation of research supported heretofore by Foundation grant CHE-8310130, under which steady progress was made toward creating an experimental and theoretical base of deduction of interionic structures. The principal methodology to be employed in the current work is analysis of electric dipole moments of modified anilinium sulfonates with strategically located substituent groups. The second project will use the comparison of medium effects in absorption and emission spectra of laser dyes at high pressure (up to 7 kbar) to sort out the contribution of hydration energies to transition energies. The interpretation of the results will provide critical information on the structure of the water network in aqueous solutions.
