Theoretical studies on atmospheric chemistry of HFE-245mc and perfluoro-ethyl formate: Reaction with OH radicals, atmospheric fate of alkoxy radical and global warming potential

Lily, Makroni; Baidya, Bidisha; Chandra, Asit K.

doi:10.1016/j.cplett.2016.12.037

Cited by 20 publications

(9 citation statements)

References 33 publications

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“…3(b) shows that of CYTOP. The chemical and physical characteristics of the PMMA are dominated by relatively short, non-polar C-H single covalent bonds with a binding energy of approximately 410 kJ/mol, which are relatively non-polar [35], [36]. However, the C = O groups in the ester bond of the PMMA give the molecule a somewhat polar character, resulting in a dielectric constant measured around 2.6∼3.0 [37], [38].…”

Section: Resultsmentioning

confidence: 99%

Improved Electrical and Temporal Stability of In-Zn Oxide Semiconductor Thin-Film Transistors With Organic Passivation Layer

Heo

Tarsoly

Lee

et al. 2022

IEEE J. Electron Devices Soc.

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Solution-processed In-Zn oxide (IZO) semiconductor thin-film transistors (TFTs) were fabricated with passivation layers of either poly(methyl methacrylate) (PMMA) or cyclic transparent optical polymer (CYTOP). According to the transfer curves obtained on the day of fabrication and after 200 days, the drain-source current of the IZO TFT without a passivation layer decreased by approximately 37 %. For the PMMA-passivated IZO TFT, it decreased by approximately 31 %. The current for the CYTOPpassivated IZO TFT showed significantly lower, only 7 % deterioration. Hence, the CYTOP-passivated IZO TFT exhibited improved electrical stability under long term ambient storage. This was attributed to the difference in the chemical composition of the two polymers, as CYTOP is a fluoropolymer, while PMMA is an ester group containing organic polymer. We show, passivation of the active layer with the proper organic film improves the stability of the high-performance solution-processed IZO TFTs.

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Section: Resultsmentioning

confidence: 99%

Improved Electrical and Temporal Stability of In-Zn Oxide Semiconductor Thin-Film Transistors With Organic Passivation Layer

Heo

Tarsoly

Lee

et al. 2022

IEEE J. Electron Devices Soc.

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“…The kinetics of the corresponding reactions, representing the antioxidant property of each of the investigated drugs, which includes the reactants, transition states, complexes, and the products of the reaction with hydroperoxyl radicals, was investigated with the Minnesota hybrid meta functional M06-2X in conjugation with the 6-31+G(d,p) basis set. M06-2X was employed because of its greater reliability in comparison with the B3LYP functional in kinetic calculations. − In fact, the M06-2X method was specially developed for thermochemistry and kinetic study of chemical reactions and since then has been used extensively for studying H-abstraction reactions. − The rate constant values obtained from the M06-2X method were comparable to the experimental results in a wide temperature range. Only the CCSD(T) method with a reasonably good correlation consistent with the triple zeta basis set (like cc-pVTZ) can provide comparable/better results, but such a method could not be used due to the large size of the systems, and therefore, the M06-2X method was followed throughout in the present study.…”

Section: Computational Methodologymentioning

confidence: 99%

Auxiliary Therapeutic Role of Cholinergic Agents: Mechanistic Insights into the Antioxidant Behavior of Alzheimer’s Disease Drugs

et al. 2022

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Repurposing of existing drugs toward new therapeutic use(s) has become an emergent area of research in current times. In this context, the antioxidant behavior of eight cholinergic drugs used in the treatment of Alzheimer’s disease (AD) was investigated theoretically. The low bond dissociation enthalpy values in all of the compounds advocated for the hydrogen atom transfer mechanism toward the observed antioxidant behavior. The kinetic study for the reaction of the drugs with hydroperoxyl radicals indicated an indirect reaction path owing to the presence of pre- and postreaction complexes. In some cases, the rate constant for the H-abstraction reaction (k = 2.8 × 103 L mol–1 s–1) is found to be close to that of a well-known non-phenolic antioxidant, α-terpinene (k = 4.3 × 103 L mol–1 s–1). Quantification of charge transfer character among the drugs with DNA bases and molecular docking calculations confirmed the groove binding model and predicted the drugs to be safe from DNA damage. A theoretical evaluation of the mechanistic details governing the antioxidant property along with the proven stress reversal ability of these AD drugs provided new insights to design and develop more efficient drugs with dual therapeutic potential.

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“…Geometry optimization and vibrational frequency calculations for stable parent molecules, products, intermediate radicals, and transition state structures for the OH radical reaction with CF 2 CHF were performed using the hybrid density functional theory method at the M06-2X level with the 6-311++G(2d,d,p) and aug-cc-pVDZ basis sets as well as the composite CBS-QB3 method . Previous studies showed that reaction pathways and the kinetic analysis of fluorinated alkanes/alkenes can be determined accurately by the use of the M06-2X level of theory. − The activation barrier computed by M06-2X in this study is in satisfactory agreement with CBS-QB3 calculations. The absence of imaginary frequencies is verified to confirm the stable structures for molecules and radicals at their true minima for each respective level of theory.…”

Section: Methodsmentioning

confidence: 99%

Kinetic Analysis of Unimolecular Reactions Following the Addition of the Hydroxyl Radical to 1,1,2-Trifluoroethene

2021

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Fluorinated olefins are valued chemicals in industry, especially as heat transfer fluids in refrigeration applications. As these volatile compounds are widely used, they may be released into the atmosphere, and investigation of their reactions in the atmosphere are therefore of importance. The kinetic analysis of the reaction mechanisms of trifluoroethene (CF 2 CHF) with hydroxyl radicals is studied using computational chemistry at the M06-2X level with the 6-311+ +G(2d,d,p) and aug-cc-pVDZ basis sets as well as the composite CBS-QB3 method. Rate coefficients for the proposed mechanisms are calculated using transition state theory (TST) with tunneling corrections. The calculated rate constants for OH addition to CF 2 CHF are in excellent agreement with experimental values. Kinetic parameters as a function of temperature and pressure are evaluated for the chemically activated formation and unimolecular dissociation of hydroxylfluoroalkyl intermediates. Important forward reactions result in adduct stabilization, H atoms, hydrogen fluoride (HF) via molecular elimination, and formation of fluorinated carbonyl radicals with CF 2 (O) and CHF(O) product channels. Stabilization of initial adducts along with HF elimination are important reaction pathways under high pressure and low temperatures. Important HF eliminations and H atom transfers primarily involve H atoms from the hydroxyl group, as the C−H bonds on or adjacent to carbons with F atoms are stronger and show high barriers to H atom transfer.

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Theoretical studies on atmospheric chemistry of HFE-245mc and perfluoro-ethyl formate: Reaction with OH radicals, atmospheric fate of alkoxy radical and global warming potential

Cited by 20 publications

References 33 publications

Improved Electrical and Temporal Stability of In-Zn Oxide Semiconductor Thin-Film Transistors With Organic Passivation Layer

Improved Electrical and Temporal Stability of In-Zn Oxide Semiconductor Thin-Film Transistors With Organic Passivation Layer

Auxiliary Therapeutic Role of Cholinergic Agents: Mechanistic Insights into the Antioxidant Behavior of Alzheimer’s Disease Drugs

Kinetic Analysis of Unimolecular Reactions Following the Addition of the Hydroxyl Radical to 1,1,2-Trifluoroethene

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