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Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
The theoretical comparison between two model NO carriers, MeSNO and MeSeNO
1Department of Chemistry, National Taiwan University, 106, Taipei, Taiwan, Republic of China. chinhunglai@ntu.edu.tw
Journal of Molecular Modeling
|October 18, 2007
Summary
Selenium-nitrososelenols (MeSeNO) are less stable than sulfur-nitrosothiols (MeSNO) in decomposition. However, MeSeNO has a higher transnitrosation barrier than MeSNO in gas phase, but becomes barrierless in water.
Area of Science:
- Computational chemistry
- Quantum chemistry
- Organic chemistry
Background:
- S-nitrosothiols (SNO) and Se-nitrososelenols (SeNO) are important in biological systems.
- Understanding their reactivity is crucial for biological and chemical applications.
- Previous studies have explored their decomposition and transnitrosation reactions.
Purpose of the Study:
- To compare the stability and reactivity of MeSNO and MeSeNO using computational methods.
- To investigate the reaction mechanisms of transnitrosation in both gas and aqueous phases.
- To elucidate the influence of solvent effects on reaction pathways and energy barriers.
Main Methods:
- Hybrid DFT functional (MPW1LYP) was employed for theoretical calculations.
- Unimolecular decomposition and transnitrosation reactions were studied.
- Polarizable Continuum Model (PCM) was used to simulate water solvent effects.
Main Results:
- Se-nitrososelenols exhibit greater instability in unimolecular decomposition compared to S-nitrosothiols due to electronic effects.
- In the gas phase, MeSeNO shows a higher transnitrosation barrier than MeSNO, irrespective of the nucleophile.
- In aqueous solution, transnitrosation reactions proceed via concerted pathways, unlike the two-step mechanism in the gas phase.
- Transnitrosation barriers for MeSNO decrease from gas to aqueous phase, while MeSeNO reactions become nearly barrierless in water.
Conclusions:
- Electronic effects significantly influence the stability of SNO and SeNO compounds.
- Reaction mechanisms for transnitrosation differ substantially between the gas and aqueous phases.
- Solvent effects play a critical role in modulating the reactivity and energetics of these nitroselenols and nitrosothiols.
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