Neutral Radicals in the Reaction of β-Carotene with NO2 and NO: Computational Study and Simulation of the EPR Spectra

Mendiara, S. N.; Perissinotti, L. J.

doi:10.1007/s00723-015-0732-x

Cited by 1 publication

(7 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The stationary point was found but the convergence criteria were reached by only three of the required four cases [10]. In the present work, we have the opportunity of showing and solving the mistake.…”

Section: ○ Cyclic Nitroxides Formed By Internal Cyclization Of the Nimentioning

confidence: 82%

“…Unfortunately, in our 2009 manuscript, the sixth equation had one mistake, we must write P 1 instead of P 2 [9]. In the 2015 manuscript, the rate constants k i (i = 1 to 7) were not written above the arrows [10].…”

Section: Kinetic Measurementsmentioning

confidence: 98%

“…However, the kinetic analysis generated poor concentrations for P 1 , which represented the allylic radical intermediates. In addition, finally, with the aid of the computational methods, the hypothesis of the formation of cyclic nitroxides was favored [10]. On the basis of the kinetic studies, it was reasonable to propose intermediates of the nitroxide type.…”

Section: Carotenoidsmentioning

confidence: 99%

“…The software used allowed to obtain the values of energy of each structure, which permitted to evaluate the relative stability of the radicals. Also, the software provided us the isotropic hfccs of each nucleus of the radical intermediates proposed [10].…”

Section: Carotenoidsmentioning

confidence: 99%

“…and P 43 (nitroxide) from P 10 (9 or 9') , a cyclic nitroxide of eight atoms [10]. Simulations were also carried out considering the contribution of the β-carotene neutral radicals or allylic neutral radicals.…”

Section: ○ Cyclic Nitroxides Formed By Internal Cyclization Of the Nimentioning

confidence: 99%

See 4 more Smart Citations

β‐Carotene and Free Radical Reactions with Nitrogen Oxides

Mendiara¹,

Perissinotti²

2017

Carotenoids

View full text Add to dashboard Cite

The following presentation is based on experimental work we have already developed and published. We investigated the nitrogen oxides in different solvents and analyzed their reaction with β-carotene. The electron paramagnetic resonance spectroscopy (EPR) and ultraviolet and visible (UV-vis) spectroscopy were applied to investigate the reaction of β-carotene with nitrogen dioxide and nitric oxide in both pure dioxane and dioxane/ water solvent. Free radicals were detected and evaluated with the EPR technique, which is highly selective and sensitive. A reaction mechanism was proposed on the basis of the experimental kinetic and EPR results. The validity of the mechanism was checked by applying simulation set up conditions that reproduced the results achieved. The radical intermediates proposed in the reaction: the β-carotene neutral radicals and the cyclic nitroxide neutral radicals were theoretically studied. For that purpose, the density functional theory (DFT) level was applied, selecting the most suitable method, the unrestricted Becke-style 3-parameter with the Lee-Yang-Parr correlation functional (UB3LYP) and the 6-31G(d) basis sets (d orbital functions). We developed an appropriate discussion on the importance of carotenoids compounds and their reactions in biological media. Also, we evaluated the role and the possible reactions of nitroxide intermediates.

show abstract

Section: ○ Cyclic Nitroxides Formed By Internal Cyclization Of the Nimentioning

confidence: 82%

Section: Kinetic Measurementsmentioning

confidence: 98%

Section: Carotenoidsmentioning

confidence: 99%

Section: Carotenoidsmentioning

confidence: 99%

Section: ○ Cyclic Nitroxides Formed By Internal Cyclization Of the Nimentioning

confidence: 99%

See 3 more Smart Citations