The Experts below are selected from a list of 33 Experts worldwide ranked by ideXlab platform
Gennady I Nikishin - One of the best experts on this subject based on the ideXlab platform.
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a rearrangement of 1 hydroperoxy 2 oxabicycloalkanes into lactones of ω acyloxy ω 3 hydroxyalkanoic acids related to the Criegee Reaction
Tetrahedron Letters, 2002Co-Authors: Yuri N Ogibin, A O Terentev, A V Kutkin, Gennady I NikishinAbstract:Abstract 1-Hydroperoxy-2-oxabicyclo[ n .4.0]alkanes ( n =3, 4, 5 and 10) on heating with formic or acetic acid containing a catalytic amount of sulfuric acid undergo a rearrangement into lactones of ω-acyloxy-(ω-3)-hydroxyalkanoic acids by a mechanism related to the Criegee Reaction.
Joseph S. Francisco - One of the best experts on this subject based on the ideXlab platform.
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Heteroatom Tuning of Bimolecular Criegee Reactions and Its Implications.
Angewandte Chemie, 2016Co-Authors: Manoj Kumar, Joseph S. FranciscoAbstract:High-level quantum-chemical calculations have been performed to understand the key reactivity determinants of bimolecular Reactions of Criegee intermediates and H2X (X=O, S, Se, and Te). Criegee intermediates are implicated as key intermediates in atmospheric, synthetic organic, and enzymatic chemistry. Generally, it is believed that the nature and location of substituents at the carbon of the Criegee intermediate play a key role in determing the reactivity. However, the present work suggests that it is not only the substitution of the Criegee intermediate, but the nature of the heteroatom in H2X that also plays a crucial role in determining the reactivity of the interaction between the Criegee intermediate and H2X. The barriers for the Reactions of Criegee intermediates and H2X satisfy an inverse correlation with the bond strength of X−H in H2X, and a direct correlation with the first pKa of H2X. This heteroatom tuning causes a substantial barrier lowering of 8–11 kcal mol−1 in the Criegee Reaction barrier in going from H2O to H2Te. An important implication of these results is that the Reaction of the Criegee intermediate and H2S could be a source of thioaldehydes, which are important in plantery atmospheres and synthetic organic chemistry. By performing the Reaction of Criegee intermediates and H2S under water or acid catalysis, thioladehydes could be detected in a hydrogen-bonded complexed state, which is significantly more stable than their uncomplexed form. As a result, simpler aliphatic thioaldehydes could be selectively synthesized in the laboratory, which, otherwise, has been a significant synthetic challenge because of their ability to oligomerize.
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New Mechanistic Pathways for Criegee-Water Chemistry at the Air/Water Interface
Journal of the American Chemical Society, 2016Co-Authors: Manoj Kumar, Jie Zhong, Lei Li, Joseph S. Francisco, Xiao Cheng ZengAbstract:Understanding Criegee chemistry has become one of central topics in atmospheric research recently. The Reaction of Criegee intermediates with gas-phase water clusters has been widely viewed as a key Criegee Reaction in the troposphere. However, the effect of aerosols or clouds on Criegee chemistry has received little attention. In this work, we have investigated the Reaction between the smallest Criegee intermediate, CH2OO, and water clusters in the gas phase, as well as at the air/water surface using ab initio quantum chemical calculations and adaptive buffered force quantum mechanics/molecular mechanics (QM/MM) dynamics simulations. Our simulation results show that the typical time scale for the Reaction of CH2OO with water at the air/water interface is on the order of a few picoseconds, 2–3 orders of magnitude shorter than that in the gas phase. Importantly, the adbf-QM/MM dynamics simulations suggest several Reaction pathways for the CH2OO + water Reaction at the air/water interface, including the loo...
Manoj Kumar - One of the best experts on this subject based on the ideXlab platform.
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Heteroatom Tuning of Bimolecular Criegee Reactions and Its Implications.
Angewandte Chemie, 2016Co-Authors: Manoj Kumar, Joseph S. FranciscoAbstract:High-level quantum-chemical calculations have been performed to understand the key reactivity determinants of bimolecular Reactions of Criegee intermediates and H2X (X=O, S, Se, and Te). Criegee intermediates are implicated as key intermediates in atmospheric, synthetic organic, and enzymatic chemistry. Generally, it is believed that the nature and location of substituents at the carbon of the Criegee intermediate play a key role in determing the reactivity. However, the present work suggests that it is not only the substitution of the Criegee intermediate, but the nature of the heteroatom in H2X that also plays a crucial role in determining the reactivity of the interaction between the Criegee intermediate and H2X. The barriers for the Reactions of Criegee intermediates and H2X satisfy an inverse correlation with the bond strength of X−H in H2X, and a direct correlation with the first pKa of H2X. This heteroatom tuning causes a substantial barrier lowering of 8–11 kcal mol−1 in the Criegee Reaction barrier in going from H2O to H2Te. An important implication of these results is that the Reaction of the Criegee intermediate and H2S could be a source of thioaldehydes, which are important in plantery atmospheres and synthetic organic chemistry. By performing the Reaction of Criegee intermediates and H2S under water or acid catalysis, thioladehydes could be detected in a hydrogen-bonded complexed state, which is significantly more stable than their uncomplexed form. As a result, simpler aliphatic thioaldehydes could be selectively synthesized in the laboratory, which, otherwise, has been a significant synthetic challenge because of their ability to oligomerize.
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New Mechanistic Pathways for Criegee-Water Chemistry at the Air/Water Interface
Journal of the American Chemical Society, 2016Co-Authors: Manoj Kumar, Jie Zhong, Lei Li, Joseph S. Francisco, Xiao Cheng ZengAbstract:Understanding Criegee chemistry has become one of central topics in atmospheric research recently. The Reaction of Criegee intermediates with gas-phase water clusters has been widely viewed as a key Criegee Reaction in the troposphere. However, the effect of aerosols or clouds on Criegee chemistry has received little attention. In this work, we have investigated the Reaction between the smallest Criegee intermediate, CH2OO, and water clusters in the gas phase, as well as at the air/water surface using ab initio quantum chemical calculations and adaptive buffered force quantum mechanics/molecular mechanics (QM/MM) dynamics simulations. Our simulation results show that the typical time scale for the Reaction of CH2OO with water at the air/water interface is on the order of a few picoseconds, 2–3 orders of magnitude shorter than that in the gas phase. Importantly, the adbf-QM/MM dynamics simulations suggest several Reaction pathways for the CH2OO + water Reaction at the air/water interface, including the loo...
Yuri N Ogibin - One of the best experts on this subject based on the ideXlab platform.
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a rearrangement of 1 hydroperoxy 2 oxabicycloalkanes into lactones of ω acyloxy ω 3 hydroxyalkanoic acids related to the Criegee Reaction
Tetrahedron Letters, 2002Co-Authors: Yuri N Ogibin, A O Terentev, A V Kutkin, Gennady I NikishinAbstract:Abstract 1-Hydroperoxy-2-oxabicyclo[ n .4.0]alkanes ( n =3, 4, 5 and 10) on heating with formic or acetic acid containing a catalytic amount of sulfuric acid undergo a rearrangement into lactones of ω-acyloxy-(ω-3)-hydroxyalkanoic acids by a mechanism related to the Criegee Reaction.
A O Terentev - One of the best experts on this subject based on the ideXlab platform.
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a rearrangement of 1 hydroperoxy 2 oxabicycloalkanes into lactones of ω acyloxy ω 3 hydroxyalkanoic acids related to the Criegee Reaction
Tetrahedron Letters, 2002Co-Authors: Yuri N Ogibin, A O Terentev, A V Kutkin, Gennady I NikishinAbstract:Abstract 1-Hydroperoxy-2-oxabicyclo[ n .4.0]alkanes ( n =3, 4, 5 and 10) on heating with formic or acetic acid containing a catalytic amount of sulfuric acid undergo a rearrangement into lactones of ω-acyloxy-(ω-3)-hydroxyalkanoic acids by a mechanism related to the Criegee Reaction.