Oxygen-Generating Gel Systems Induced by Visible Light and Application to Artificial Photosynthesis

2012 ◽  
Vol 1418 ◽  
Author(s):  
Kosuke Okeyoshi ◽  
Ryo Yoshida
Keyword(s):  
Visible Light ◽  
Functional Groups ◽  
Electrostatic Interactions ◽  
Artificial Photosynthesis ◽  
Polymer Network ◽  
Steric Effects ◽  
Colloidal Nanoparticles ◽  
Graft Polymer ◽  
Hierarchical Network ◽  
Novel Strategy

ABSTRACTToward complete artificial photosynthesis systems to generate hydrogen and oxygen using visible light and water, we firstly design and fabricate oxygen-generating gel systems using the electrostatic interactions of ionic functional groups and steric effects of a polymer network. By using a graft polymer chain with Ru(bpy)32+ units as sensitizers to closely arrange RuO2 nanoparticles as catalyst, the functional groups transmit multiple electrons cooperatively to generate oxygen. In this study, a novel strategy is shown to design a hierarchical network structure using colloidal nanoparticles and macromonomers.

Visible Light-Promoted Catalytic Ring-Opening Isomerization of 1,2-Disubstituted Cyclopropanols to Linear Ketones

2019 ◽  
Author(s):  
Marharyta V. Laktsevich-Iskryk ◽  
Nastassia A. Varabyeva ◽  
Volha V. Kazlova ◽  
Vladimir N. Zhabinskii ◽  
Vladimir A. Khripach ◽  
...  
Keyword(s):  
Visible Light ◽  
Functional Groups ◽  
Ring Opening ◽  
Radical Intermediates ◽  
Reaction Proceeds

In this article, we report a photocatalytic protocol for the isomerization of 1,2-disubstituted cyclopropanols to linear ketones. The reaction proceeds <i>via</i> radical intermediates and tolerates various functional groups.

Visible Light-Promoted Catalytic Ring-Opening Isomerization of 1,2-Disubstituted Cyclopropanols to Linear Ketones

2019 ◽  
Author(s):  
Marharyta V. Laktsevich-Iskryk ◽  
Nastassia A. Varabyeva ◽  
Volha V. Kazlova ◽  
Vladimir N. Zhabinskii ◽  
Vladimir A. Khripach ◽  
...  
Keyword(s):  
Visible Light ◽  
Functional Groups ◽  
Ring Opening ◽  
Radical Intermediates ◽  
Reaction Proceeds

In this article, we report a photocatalytic protocol for the isomerization of 1,2-disubstituted cyclopropanols to linear ketones. The reaction proceeds <i>via</i> radical intermediates and tolerates various functional groups.

Visible Light-Mediated Oxidative Debenzylation

2020 ◽  
Author(s):  
Cristian Cavedon ◽  
Eric T. Sletten ◽  
Amiera Madani ◽  
Olaf Niemeyer ◽  
Peter H. Seeberger ◽  
...  
Keyword(s):  
Reaction Time ◽  
Visible Light ◽  
Functional Groups ◽  
Continuous Flow ◽  
Protecting Groups ◽  
Benzyl Ether ◽  
Complex Molecules ◽  
Protective Groups ◽  
Benzyl Ethers ◽  
Harsh Conditions

Protecting groups are key in the synthesis of complex molecules such as carbohydrates to distinguish functional groups of similar reactivity. The harsh conditions required to cleave stable benzyl ether protective groups are not compatible with many other protective and functional groups. The mild, visible light-mediated debenzylation disclosed here renders benzyl ethers orthogonal protective groups. Key to success is the use of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as stoichiometric or catalytic photooxidant such that benzyl ethers can be cleaved in the presence of azides, alkenes, and alkynes. The reaction time for this transformation can be reduced from hours to minutes in continuous flow. <br>

Hydration Free Energies of Organic Molecules in the FreeSolv Database Calculated with Polarized Atom In Molecules Atomic Charges and the GAFF Force Field.

2018 ◽  
Author(s):  
Maximiliano Riquelme ◽  
Alejandro Lara ◽  
David L. Mobley ◽  
Toon Vestraelen ◽  
Adelio R Matamala ◽  
...  
Keyword(s):  
Force Field ◽  
Functional Groups ◽  
Electrostatic Interactions ◽  
Organic Molecules ◽  
Force Fields ◽  
Chemical Elements ◽  
Atomic Charges ◽  
Free Energies ◽  
Molecular Systems ◽  
Solvent Model

<div>Computer simulations of bio-molecular systems often use force fields, which are combinations of simple empirical atom-based functions to describe the molecular interactions. Even though polarizable force fields give a more detailed description of intermolecular interactions, nonpolarizable force fields, developed several decades ago, are often still preferred because of their reduced computation cost. Electrostatic interactions play a major role in bio-molecular systems and are therein described by atomic point charges.</div><div>In this work, we address the performance of different atomic charges to reproduce experimental hydration free energies in the FreeSolv database in combination with the GAFF force field. Atomic charges were calculated by two atoms-in-molecules approaches, Hirshfeld-I and Minimal Basis Iterative Stockholder (MBIS). To account for polarization effects, the charges were derived from the solute's electron density computed with an implicit solvent model and the energy required to polarize the solute was added to the free energy cycle. The calculated hydration free energies were analyzed with an error model, revealing systematic errors associated with specific functional groups or chemical elements. The best agreement with the experimental data is observed for the MBIS atomic charge method, including the solvent polarization, with a root mean square error of 2.0 kcal mol<sup>-1</sup> for the 613 organic molecules studied. The largest deviation was observed for phosphor-containing molecules and the molecules with amide, ester and amine functional groups.</div>

Naked-Eye Detection of Hg(II) Ions by Visible Light-Induced Polymerization Initiated by a Hg(II)-Selective Photoredox Catalyst

2021 ◽  
Author(s):  
Hyungwook Kim ◽  
Young Jae Jung ◽  
Jungkyu K. Lee
Keyword(s):  
Visible Light ◽  
Signal Amplification ◽  
Eye Detection ◽  
Naked Eye ◽  
Turn On ◽  
Novel Strategy ◽  
Amplification Strategy ◽  
Naked Eye Detection

We developed a novel strategy for signal amplification strategy using a visible light-induced photopolymerization, initiated by a selective turn-on photoredox catalyst. As photoredox catalysts, fluorescein derivatives are able to initiate...

Visible light responsive metalloporphyrin- sensitized TiO2 nanotube arrays for artificial photosynthesis of methane production

2022 ◽  
Author(s):  
Tongxin Xiao ◽  
Ying Chen ◽  
Yuning Liang
Keyword(s):  
Global Warming ◽  
Visible Light ◽  
Methane Production ◽  
Artificial Photosynthesis ◽  
Tio2 Nanotube Arrays ◽  
Tio2 Nanotube ◽  
Energy Sources ◽  
Nanotube Arrays ◽  
Sunlight Irradiation

The conversion of CO2 and water into valuable chemicals under sunlight irradiation is of great significance for solving the widespread problems of both lacking energy sources and global warming. In...

Protection of menhaden oil from oxidation in Pickering emulsion-based delivery systems with α-lactalbumin-chitosan colloidal nanoparticle

2021 ◽  
Author(s):  
Jiang Yi ◽  
Qingyu He ◽  
Yuting Fan
Keyword(s):  
Electrostatic Interactions ◽  
Hydrophobic Surface ◽  
Pickering Emulsion ◽  
Delivery Systems ◽  
Colloidal Nanoparticles ◽  
Menhaden Oil

In this study, α-lactalbumin-chitosan (ALA-CHI) colloidal nanoparticles were spontaneously formed mainly through electrostatic interactions for stabilizing Pickering emulsion. The film of ALA-CHI colloidal nanoparticles had more hydrophobic surface in nature...

scholarly journals Exploration of an Extracellular Polymeric Substance from Earthworm Gut Bacterium (Bacillus licheniformis) for Bioflocculation and Heavy Metal Removal Potential

2020 ◽  
Vol 10 (1) ◽  
pp. 349 ◽  
Author(s):  
Jayanta Kumar Biswas ◽  
Anurupa Banerjee ◽  
Binoy Sarkar ◽  
Dibyendu Sarkar ◽  
Santosh Kumar Sarkar ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Functional Groups ◽  
Bacillus Licheniformis ◽  
Extracellular Polymeric Substance ◽  
Electrostatic Interactions ◽  
Metal Removal ◽  
Metal Sorption ◽  
Polymeric Substance ◽  
13C Nuclear Magnetic Resonance ◽  
Earthworm Gut

The present study shows the potential of an extracellular polymeric substance (EPS) produced by Bacillus licheniformis strain KX657843 isolated from earthworm (Metaphire posthuma) gut in the sorption of Cu(II) and Zn(II) and in flocculation. After harvesting bacterial cells from sucrose supplemented denitrifying culture medium, the EPS was extracted following ethanolic extraction method. The Fourier Transform Infrared Spectroscopy (FTIR) and 1H and 13C Nuclear Magnetic Resonance (NMR) of EPS revealed its functional groups, electronegative constituents, unsaturated carbon, and carbonyl groups. The negatively charged functional groups of carbohydrates and protein moiety of the EPS endowed it with heavy metal binding capacity through electrostatic interactions. The highest flocculation activity (83%) of EPS was observed at 4 mg L−1 and pH 11. The metal sorption by EPS increased with increasing pH. At pH 8, the EPS was able to remove 86 and 81% Cu(II) and Zn(II), respectively, from a 25 mg L−1 metal solution. 94.8% of both the metals at 25 mg L−1 metal solutions were removed by EPS at EPS concentration of 100 mg L−1. From Langmuir isotherm model, the maximum sorption capacities of EPS were calculated to be 58.82 mg g−1 for Cu(II) and 52.45 mg g−1 for Zn(II). The bacterial EPS showed encouraging flocculating and metal sorption properties. The potential to remove Cu(II) and Zn(II) implies that the EPS obtained from the earthworm gut bacteria can be used as an effective agent for environmental remediation of heavy metals and in bioflocculation.

A novel strategy for LED re-utilization for visible light communications

Optik ◽  
2017 ◽  
Vol 151 ◽  
pp. 88-97 ◽  
Author(s):  
F. Seguel ◽  
A. Dehghan Firoozabadi ◽  
P. Adasme ◽  
I. Soto ◽  
N. Krommenacker ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Communications ◽  
Novel Strategy

scholarly journals A Theoretical Study of the Adsorption Process of B-aflatoxins Using Pyracantha koidzumii (Hayata) Rehder Biomasses

Toxins ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 283
Author(s):  
Abraham Méndez-Albores ◽  
René Escobedo-González ◽  
Juan Manuel Aceves-Hernández ◽  
Perla García-Casillas ◽  
María Inés Nicolás-Vázquez ◽  
...  
Keyword(s):  
Functional Groups ◽  
Electrostatic Interactions ◽  
Density Functional ◽  
Ph Value ◽  
Theoretical Calculations ◽  
Basis Set ◽  
Hydroxyl Group ◽  
Biosorption Process

Employing theoretical calculations with density functional theory (DFT) using the B3LYP/6-311++G(d,p) functional and basis set, the interaction of the aflatoxin B1 (AFB1) molecule and the functional groups present in the Pyracantha koidzumii biosorbent was investigated. Dissociation free energy and acidity equilibrium constant values were obtained theoretically both in solution (water) and gas phases. Additionally, the molecular electrostatic potential for the protonated molecules was calculated to verify the reactivity. Thus, methanol (hydroxyl group), methylammonium ion (amino group), acetate ion (carboxyl group), and acetone (carbonyl group), were used as representatives of the substrates present in the biomass; these references were considered using the corresponding protonated or unprotonated forms at a pH value of 5. The experimental infrared spectrophotometric data suggested the participation of these functional groups in the AFB1 biosorption process, indicating that the mechanism was dominated by electrostatic interactions between the charged functional groups and the positively charged AFB1 molecule. The theoretical determination indicated that the carboxylate ion provided the highest interaction energy with the AFB1 molecule. Consequently, an enriched biosorbent with compounds containing carboxyl groups could improve the yield of the AFB1 adsorption when using in vitro and in vivo trials.

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