Solute--water interactions: do polyhydroxy compounds after the properties of water?

Area of Science:

• Physical Chemistry
• Solution Chemistry
• Biophysical Chemistry

Background:

• Interactions between polyhydroxy compounds (PHCs) and water are crucial for understanding solution behavior.
• Hydrogen bonding governs the interactions between PHCs and water molecules.
• The arrangement of -OH groups on PHC molecules significantly impacts these interactions.

Purpose of the Study:

• To elucidate the role of hydrogen bonding in PHC-water interactions.
• To explain the preferential solvation of specific PHC conformers by aqueous solvents.
• To investigate the origins of macroscopic phenomena like bound water and gel formation in PHC solutions.

Main Methods:

• Analysis of hydrogen bonding interactions between PHCs and water.
• Conformational analysis of PHC molecules in aqueous solution.
• Investigation of hydration forces and their range of influence.
• Correlation of molecular interactions with macroscopic solution properties.

Main Results:

• Aqueous solvents favor PHC conformers with equatorial -OH groups due to spatial compatibility.
• This preferential solvation leads to supersaturation and incomplete freezing (bound water).
• Hydration forces, decaying exponentially within 3 nm, govern water structure perturbation.
• Marginal single hydrogen bond effects collectively cause macroscopic phenomena.

Conclusions:

• Hydrogen bonding and hydration forces dictate PHC-water interactions and solution properties.
• The concept of 'bound water' arises from preferential solvation of specific PHC conformers.
• These molecular interactions are responsible for observable phenomena such as gel formation and dehydration protection in PHC solutions.