Computational Investigation on Interactions Between Some Munitions Compounds and Humic Substances

2021 ◽  
Author(s):  
Timothy C. Schutt ◽  
Manoj K. Shukla
Keyword(s):  
Humic Acid ◽  
Electron Affinity ◽  
Density Functional ◽  
Model Compound ◽  
Water Solution ◽  
Natural Soil ◽  
Computational Investigation ◽  
Binding Ability ◽  
Functional Theory ◽  
Insensitive Munitions

Humic acid substances (HAs) in natural soil and sediment environments effect the retention and degradation of insensitive munitions compounds and legacy high explosives (MCs): DNAN, DNi- NH4+, nMNA, NQ, NTO (neutral and anionic forms), TNT, and RDX.A humic acid model compound has been considered using molecular dynamics, thermodynamic integration, and density functional theory to characterize the munition binding ability, ionization potential, and electron affinity compared to that in the water solution. Humic acids bind most compounds and act as both a sink and source for electrons. Ionization potentials suggest HAs are more susceptible to oxidation than the MCs studied. The electron affinity of HAs are very conformation-dependent and spans the same range as the munition compounds. When HAs and MCs are complexed the HAs tend to radicalize first thus buffering MCs against reductive as well as oxidative attacks.

Exploring chemistry features of favipiravir in octanol/water solutions

2021 ◽  
pp. 1-12
Author(s):  
Halimeh Rajabzadeh ◽  
Ayla Sharafat ◽  
Maryam Abbasi ◽  
Maryam Eslami Gharaati ◽  
Iraj Alipourfard
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Partition Coefficients ◽  
Density Functional ◽  
Water Solution ◽  
Peptide Group ◽  
Functional Theory ◽  
Water Solutions ◽  
Group Rotations ◽  
Heterocyclic Structure

Favipiravir (Fav) has become a well-known drug for medication of patients by appearance of COVID-19. Heterocyclic structure and connected peptide group could make changes for Fav yielding different features from those required features. Therefore, it is indeed a challenging task to prepare a Fav compound with specific features of desired function. In this work, existence of eight Fav structures by tautomeric formations and peptide group rotations were obtained using density functional theory (DFT) optimization calculations. Gas phase, octanol solution, and water solution were employed to show impact of solution on features of Fav besides obtaining partition coefficients (LogP) for Fav compounds. Significant impacts of solutions were seen on features of Fav with the obtained LogP order: Fav-7 >  Fav-8 >  Fav-4 >  Fav-3 >  Fav-2 >  Fav-5 >  Fav-1 >  Fav-6. As a consequence, internal changes yielded significant impacts on features of Fav affirming its carful medication of COVID-19 patients.

Computational investigation of NH3 adsorption and dehydrogenation on a W-modified Fe(111) surface

2015 ◽  
Vol 17 (45) ◽  
pp. 30598-30605 ◽  
Author(s):  
Ming-Kai Hsiao ◽  
Chia-Hao Su ◽  
Ching-Yang Liu ◽  
Hui-Lung Chen
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Computational Investigation ◽  
Functional Theory ◽  
Nh3 Adsorption ◽  
Tungsten Metal

We employed monolayer tungsten metal to modify the Fe(111) surface, denoted as W@Fe(111), and calculated the adsorption and dehydrogenation behaviors of NH3 on W@Fe(111) surface via first-principles calculations based on density functional theory (DFT).

scholarly journals Н-комплексы 1,2-нафтохинона с молекулами воды в водном растворе и их влияние на сдвиги полос поглощения

2021 ◽  
Vol 129 (5) ◽  
pp. 599
Author(s):  
С.Н. Цеплина ◽  
E.E. Цеплин
Keyword(s):  
Quantum Chemical ◽  
Continuum Model ◽  
Density Functional ◽  
Water Solution ◽  
Polarizable Continuum Model ◽  
Water Molecules ◽  
Absorption Bands ◽  
Functional Theory ◽  
Polarizable Continuum ◽  
Polar Water

Optical absorption spectra of 1,2-naphthoquinone in non-polar (n-hexane) and polar (water) solvents were obtained. It is shown that the use of quantum chemical calculations based on time-dependent density functional theory (TDDFT B3LYP/6-311+G(d, p)) with the polarizable continuum model (PCM) for calculating 1,2-naphthoquinone in a solution of n-hexane and hydrogen complex of 1,2-naphthoquinone with two water molecules in an aqueous medium describes well the shifts of the absorption bands of 1,2-naphthoquinone in a water solution compared to a solution in n-hexane. Based on the analysis of deviations of the calculated band shifts from the experimental ones, the question of the formation of 1,2-naphthoquinone hydrogen complexes with n water molecules (n = 1-4) in an aqueous solution is considered.

scholarly journals Theoretical Study on Influence of Cobalt Oxides Valence State Change for C6H5COOH Pyrolysis

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 197
Author(s):  
Si-Mei Fu ◽  
Yue Zhao ◽  
Jiang-Tao Liu ◽  
Wen-Sheng Liang ◽  
Gang-Sen Li ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Valence State ◽  
Energy Barrier ◽  
Density Functional ◽  
Model Compound ◽  
Theoretical Study ◽  
Cobalt Oxides ◽  
State Change ◽  
Pyrolysis Process ◽  
Functional Theory

Benzoic acid (C6H5COOH) is selected as coal-based model compound with Co compounds (Co3O4, CoO and Co) as the catalysts, and the influence of the valence state change of the catalyst for pyrolysis process is investigated using density functional theory (DFT). DFT results shows that the highest energy barrier of C6H5COOH pyrolysis is in the following order: Ea(CoO) <Ea(Co3O4) <Ea(no catalyst) <Ea(Co). In general, Co3O4 catalyst accelerates C6H5COOH pyrolysis. Then, the catalytic activity further increases when Co3O4 is reduced to CoO. Finally, Co shows no activity for C6H5COOH pyrolysis due to the reduction of CoO to metallic Co.

scholarly journals Computational investigation of Zn-doped and undoped SrEu2Fe2O7 as potential mixed electron and proton conductors

RSC Advances ◽  
2020 ◽  
Vol 10 (66) ◽  
pp. 39988-39994
Author(s):  
Zongzi Jin ◽  
Ranran Peng ◽  
Yunpeng Xia ◽  
Zhenbin Wang ◽  
Wei Liu
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Oxygen Vacancies ◽  
Density Functional Theory Calculations ◽  
Proton Conductors ◽  
Computational Investigation ◽  
Functional Theory ◽  
Proton Defects

Density functional theory calculations are employed to investigate the formation and conducting behaviors of oxygen vacancies and proton defects in Ruddlesden–Popper oxide SrEu2Fe2O7.

scholarly journals The Antioxidant Capability of Higenamine: Insights from Theory

Antioxidants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 358
Author(s):  
Isabella Romeo ◽  
Angela Parise ◽  
Annia Galano ◽  
Nino Russo ◽  
Juan Raúl Alvarez-Idaboy ◽  
...  
Keyword(s):  
Density Functional ◽  
Water Solution ◽  
Protective Action ◽  
Molar Fraction ◽  
Hydrogen Atom Transfer ◽  
Scavenging Activity ◽  
Ros Scavenging ◽  
Working Mechanism ◽  
Functional Theory ◽  
Ph Values

Density functional theory was employed to highlight the antioxidant working mechanism of higenamine in aqueous and lipid-like environments. Different reaction mechanisms were considered for the reaction of higenamine with the •OOH radical. The pH values and the molar fraction at physiological pH were determined in aqueous solution. The results show that the preferred reaction mechanism was the hydrogen atom transfer from the catecholic ring. The computed kinetic constants revealed that, in order to obtain reliable results, it is important to consider all the species present in water solution derived from acid–base equilibria. From the present investigation, it emerges that at physiological pH (7.4), the scavenging activity of higenamine against the •OOH radical is higher than that of Trolox, chosen as a reference antioxidant. Furthermore, higenamine results to be more efficient for that purpose than melatonin and caffeine, whose protective action against oxidative stress is frequently associated with their reactive oxygen species (ROS) scavenging activity.

Can silylenes rival transition metal systems in bond-strengthening π-back donation? A computational investigation

2014 ◽  
Vol 50 (62) ◽  
pp. 8522-8525 ◽  
Author(s):  
Amrita Pal ◽  
Kumar Vanka
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Density Functional ◽  
Computational Investigation ◽  
Functional Theory ◽  
Silylene Complexes ◽  
Back Donation ◽  
Full Quantum

Full quantum chemical calculations with density functional theory (DFT) show that bond-strengthening back-donation to a π-diborene, recently discovered for transition metal systems (Braunschweig and co-workers, Nat. Chem., 2013, 5, 115–121), would be just as favored for Main Group silylene complexes.

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