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Solvent effects on peroxynitrite structure and properties from QM/MM simulations.
Mariano C Gonzalez Lebrero1, Laura L Perissinotti, Darío A Estrin
1Departamento de Química Inorganica, Analítica y Química Física -- INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA, Buenos Aires, Argentina.
The Journal of Physical Chemistry. A
|July 27, 2006
Summary
We used quantum-classical simulations to study peroxynitrite in water. Our method accurately predicts its structure and vibrational spectrum, resolving experimental discrepancies and revealing solvent effects.
Area of Science:
- Computational Chemistry
- Physical Chemistry
- Spectroscopy
Background:
- Peroxynitrite anion is a reactive species with an important role in biological systems.
- Understanding its structure and vibrational spectrum in aqueous solution is crucial for interpreting experimental data.
- Previous studies have faced challenges in accurately predicting its properties due to computational limitations.
Purpose of the Study:
- To investigate the structure and vibrational spectrum of peroxynitrite anion in aqueous solution.
- To clarify discrepancies in experimental spectral assignments.
- To elucidate the interplay between solvation and peroxynitrite properties.
Main Methods:
- Combined quantum-classical (QM/MM) molecular dynamics simulations.
- Density Functional Theory (DFT) for the quantum mechanical part.
- TIP4P and TIP4P-FQ force fields for the molecular mechanics part.
- Validation of computational parameters using isolated peroxynitrite and small complexes.
Main Results:
- DFT methods provide better agreement with high-level ab initio calculations (CCSD(T)) compared to HF methods.
- The QM/MM approach accurately predicts the vibrational spectrum of aqueous peroxynitrite.
- The study clarifies previous experimental spectral assignments.
Conclusions:
- The developed QM/MM computational scheme effectively models aqueous peroxynitrite, including anharmonicity and solvent effects.
- This approach resolves long-standing discrepancies in experimental spectral assignments.
- The findings highlight the significant influence of solvation on peroxynitrite structure and dynamics.