Solute Specific Perturbations to Water Structure and Dynamics in Tertiary Aqueous Solution.

Area of Science:

• Physical Chemistry
• Solution Chemistry
• Biophysical Chemistry

Background:

• Water's role as a universal solvent is well-established.
• Understanding complex solutions is crucial for biological and chemical processes.
• Binary solutions' solute effects are known, but complex solutions remain challenging.

Purpose of the Study:

• To investigate solute-induced perturbations in tertiary aqueous solutions.
• To deconvolute the competing effects of trimethylamine N-oxide (TMAO) and magnesium perchlorate (Mg(ClO4)2) on water structure and dynamics.

Main Methods:

• Correlative Nuclear Magnetic Resonance (NMR) and neutron diffraction study.
• Analysis of a tertiary solution containing TMAO and Mg(ClO4)2.
• Introduction of a weighting parameter to quantify solute perturbation effectiveness.

Main Results:

• TMAO and Mg(ClO4)2 exhibit opposing effects on water structure.
• Both solutes demonstrate an additive effect on slowing water dynamics.
• TMAO was found to be 1.54 times more effective than Mg(ClO4)2 in perturbing water.

Conclusions:

• Combined NMR, neutron diffraction, and computational modeling provide deep insights into complex aqueous solutions.
• This approach allows for the deconvolution of specific solute perturbations.
• Understanding these interactions is vital for comprehending water's behavior in relevant environments.