Protic vs Aprotic Solvent Effect on Proton Transfer in 3-Hydroxyisoquinoline: A Theoretical Study

Area of Science:

• Computational chemistry
• Photochemistry
• Molecular modeling

Background:

• 3-hydroxyisoquinoline (3HIQ) is a molecule with interesting structural and electronic properties.
• Understanding its behavior in different environments is crucial for various applications.

Purpose of the Study:

• To theoretically investigate the structures, energetics, and tautomerizations of 3HIQ.
• To elucidate the role of solvent effects (implicit vs. explicit) on 3HIQ properties in both ground and excited states.

Main Methods:

• Utilized advanced computational methods: MP2 for ground state, TDDFT and CASPT2 for excited state.
• Investigated both implicit and explicit solvent models to assess their impact.

Main Results:

• Explicit solvent effects are more significant than implicit solvent effects for 3HIQ.
• Proton transfer in 3HIQ is greatly facilitated in explicit solvents (water, methanol) in the excited state.
• The reactive role of molecular solvents is linked to hydrogen bond formation.

Conclusions:

• Explicit solvent models are essential for accurately describing 3HIQ's behavior, particularly its excited-state proton transfer.
• The findings highlight the importance of considering specific solvent interactions in photochemical studies.