A long lasting sunscreen controversy of 4-aminobenzoic acid and 4-dimethylaminobenzaldehyde derivatives resolved by ultrafast spectroscopy combined with density functional theoretical study

2020 ◽  
Vol 22 (15) ◽  
pp. 8006-8020
Author(s):  
Chris Tsz-Leung Chan ◽  
Chensheng Ma ◽  
Ruth Chau-Ting Chan ◽  
Hui-Min Ou ◽  
Han-Xin Xie ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Density Functional ◽  
Ultrafast Spectroscopy ◽  
Theoretical Study ◽  
Pivotal Role ◽  
Aminobenzoic Acid ◽  
Sunscreen Agents

Photoprotection or photodamage: a pivotal role of water in regulating dynamics and molecular mechanism for efficacy of DMABA, DMAAP and PABA sunscreen agents.

scholarly journals Theoretical Study of the Microhydration of 1-Chloro and 2-Chloro Ethanol as a Clue for Their Relative Propensity Toward Dehalogenation

2018 ◽  
Author(s):  
George Petsis ◽  
Zoi Salta ◽  
Agnie M. Kosmas ◽  
Oscar Ventura
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Initial Step ◽  
Water Molecules ◽  
Water Solvent ◽  
Functional Methods ◽  
Electronic Distribution ◽  
Standard Reaction ◽  
Hydrogen Bonded

<p>This work reports a computational analysis of hydrogen bonded clusters of mono-, di-, tri- and tetra hydrates of the chlorohydrins CH<sub>3</sub>CHClOH (1ClEtOH) and CH<sub>2</sub>ClCH<sub>2</sub>OH (2ClEtOH). The goal of the study is to assess the role of the water solvent into the facilitation of the initial step for dehalogenation of these compounds, a process of interest in several contexts. Molecular orbital methods (MP2), density functional methods (B3LYP, M06 and wB97X-D) and composite model chemistries (CBS-QB3, G4) were employed to investigate the structure, electronic distribution and hydrogen-bonded structure of 7 monohydrates, 6 dihydrates, 5 trihydrates and 5 tetrahydrates of both species. Standard reaction enthalpy and standard Gibbs free reaction energy were computed for all aggregates with respect to <b><i>n</i></b> independent water molecules and with respect to the dimer, trimer and tetramer of water, respectively, in order to evaluate stability and hydrogen bonding network. The influence of the water chains on the length and vibrational frequencies, especially of the C-Cl and O-H bonds, was evaluated.</p>

Theoretical study of NHC-catalyzed C-S bond cleavage and reconstruction reaction: Mechanism, stereoselectivity, and role of catalyst

2021 ◽  
Author(s):  
Yang Wang ◽  
Yue Liu ◽  
Kaili Gong ◽  
Han Zhang ◽  
Yu Lan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Theoretical Study ◽  
Bond Cleavage ◽  
Functional Theory

A theoretical study of the mechanism of the N-heterocyclic carbene (NHC)-catalyzed C-S bond cleavage and reconstruction reaction of unsaturated thioesters was conducted using density functional theory (DFT). The origin of...

Symmetry-adapted perturbation theory study for some magnesium complexes

2012 ◽  
Vol 90 (10) ◽  
pp. 819-827
Author(s):  
Mehdi D. Esrafili ◽  
Sirous Yourdkhani
Keyword(s):  
Perturbation Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Water Molecules ◽  
Interaction Energies ◽  
Unique Role ◽  
Functional Methods ◽  
Ligand Interactions ◽  
Good Agreement

A systematic theoretical study on Mg–ligand interactions has been carried out employing both ab initio correlated wave function and density functional methods. The interactions of the Mg(CH3N2)2 moiety with BF, CO, N2, NH3, and H2O ligands have been investigated by performing calculations at the B3LYP, MP2, MP4, and CCSD(T)/6–311++G(3df,3pd) levels of theory. Results indicate that the interaction energies of the Mg(CH3N2)2–L complexes increase in the order NH3 > H2O > BF > CO > N2. Symmetry-adapted perturbation theory (SAPT) analysis has been carried out to understand the nature of the forces involved in the bonding. The SAPT results indicate that the stabilities of the Mg–L interactions are attributed mainly to electrostatic effects, while induction and dispersion forces also play a significant role. The evaluated SAPT interaction energies for the Mg(CH3N2)2–L complexes are generally in good agreement with those obtained using the supermolecule CCSD(T) methods, suggesting that SAPT is a proper method to study the intermolecular interactions in these complexes. The results also suggest an explanation for the unique role of Mg2+ as a carrier of water molecules that mediate enzymatic hydrolysis reactions.

Religious Movements in Central Africa: A Theoretical Study

1976 ◽  
Vol 18 (4) ◽  
pp. 458-475 ◽  
Author(s):  
Willy De Craemer ◽  
Jan Vansina ◽  
Renée C. Fox
Keyword(s):  
Theoretical Study ◽  
Central Africa ◽  
Pivotal Role ◽  
Religious Movements ◽  
Sociological Research ◽  
Systemic Feature ◽  
Beliefs And Values ◽  
Role Of Religion

A shared sense of discovery and frustration prompts us to write this article. Independently, from our anthropological, historical and sociological research in Zaire over a period of many years, we have been impressed with the pivotal role of religion and magic in that society. The recurrence and development of religious movements in Zaire throughout its known history is an archetypical expression of that predominance. In our view, these movements are an integral dimension of the cultures common to most parts of Zaire and to contiguous areas in Central Africa. A systemic feature of these cultures is that they are conducive to the emergence and evolution of movements with distinctive symbols, rites, beliefs and values. In turn, these movements constantly enrich the underlying cultures from which they emanate.

Laccase-Mediated Treatment of Pharmaceutical Wastes

2018 ◽  
pp. 213-252 ◽  
Author(s):  
Hamid Forootanfar ◽  
Shokouh Arjmand ◽  
Mina Behzadi ◽  
Mohammad Ali Faramarzi
Keyword(s):  
Nineteenth Century ◽  
Literature Review ◽  
Molecular Mechanism ◽  
Mechanism Of Action ◽  
Critical Review ◽  
Pivotal Role ◽  
Aquatic Environments ◽  
Review Of The Literature ◽  
Molecular Mechanism Of Action

Laccases are versatile multi-copper enzymes belonging to the superfamily of oxidase enzymes, which have been known since the nineteenth century. Recent discoveries have refined investigators' views of the potential of laccase as a magic tool for remarkable biotechnological purposes. A literature review of the capabilities of laccases, their assorted substrates, and their molecular mechanism of action now indicates the emergence of a new direction for laccase application as part of an arsenal in the fight against the contamination of water supplies by a number of frequently prescribed medications. This chapter provides a critical review of the literature and reveals the pivotal role of laccases in the elimination and detoxification of pharmaceutical contaminants in aquatic environments and wastewaters.

Mechanistic insight into H2-mediated Ni surface diffusion and deposition to form branched Ni nanocrystals: a theoretical study

2020 ◽  
Vol 22 (41) ◽  
pp. 23869-23877
Author(s):  
Yan Li ◽  
Ning Liu ◽  
Chengna Dai ◽  
Ruinian Xu ◽  
Bin Wu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Ab Initio ◽  
Surface Diffusion ◽  
Density Functional ◽  
Theoretical Study ◽  
Functional Theory ◽  
Mechanistic Insight ◽  
Insight Into

Present work investigates the kinetic role of H2 during Ni surface diffusion and deposition to generate branched Ni nanostructures by employing density functional theory (DFT) calculations and ab initio molecule dynamic (AIMD) simulations.

scholarly journals Theoretical Study of the Microhydration of 1-Chloro and 2-Chloro Ethanol as a Clue for Their Relative Propensity Toward Dehalogenation

2018 ◽  
Author(s):  
George Petsis ◽  
Zoi Salta ◽  
Agnie M. Kosmas ◽  
Oscar Ventura
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Initial Step ◽  
Water Molecules ◽  
Water Solvent ◽  
Functional Methods ◽  
Electronic Distribution ◽  
Standard Reaction ◽  
Hydrogen Bonded

<p>This work reports a computational analysis of hydrogen bonded clusters of mono-, di-, tri- and tetra hydrates of the chlorohydrins CH<sub>3</sub>CHClOH (1ClEtOH) and CH<sub>2</sub>ClCH<sub>2</sub>OH (2ClEtOH). The goal of the study is to assess the role of the water solvent into the facilitation of the initial step for dehalogenation of these compounds, a process of interest in several contexts. Molecular orbital methods (MP2), density functional methods (B3LYP, M06 and wB97X-D) and composite model chemistries (CBS-QB3, G4) were employed to investigate the structure, electronic distribution and hydrogen-bonded structure of 7 monohydrates, 6 dihydrates, 5 trihydrates and 5 tetrahydrates of both species. Standard reaction enthalpy and standard Gibbs free reaction energy were computed for all aggregates with respect to <b><i>n</i></b> independent water molecules and with respect to the dimer, trimer and tetramer of water, respectively, in order to evaluate stability and hydrogen bonding network. The influence of the water chains on the length and vibrational frequencies, especially of the C-Cl and O-H bonds, was evaluated.</p>

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