Comparison of cationic, anionic and neutral hydrogen bonded dimers

Area of Science:

• Physical Chemistry
• Biophysics
• Computational Chemistry

Background:

• Short Strong Hydrogen Bonds (SSHBs) are vital in physics, chemistry, and biology.
• SSHBs are particularly significant in enzyme catalysis, metabolism, protein folding, and proton transport.

Purpose of the Study:

• To investigate the characteristics of neutral, anionic, and cationic hydrogen bonds.
• To explore diverse homogeneous and heterogeneous hydrogen-bonded dimers.

Main Methods:

• Density Functional Theory (DFT) and Møller-Plesset second order perturbation (MP2) calculations for geometry optimization and frequency analysis.
• First principles Car-Parrinello molecular dynamics (CPMD) simulations to generate IR spectra.
• Analysis of velocity and dipole autocorrelation functions.

Main Results:

• Hydrogen bond energy shows an inverse fourth-power relationship with the r(O/N-H) distance.
• Proton acceptor atom polarization significantly contributes to the binding energy across various hydrogen bond types.
• Detailed insights into the nature of hydrogen-bonded dimers, including SSHBs.

Conclusions:

• The findings deepen the understanding of hydrogen bond dynamics and energy contributions.
• This research provides a foundation for further studies on SSHBs in complex systems.
• The inverse relationship between bond energy and distance offers a predictive model for hydrogen bond strength.