Solvent and ion pairing effects on the reaction entropy for the electroreduction of aromatic molecules

1987 ◽  
Vol 219 (1-2) ◽  
pp. 209-219 ◽  
Author(s):  
Jan S. Jaworski
Keyword(s):  
Ion Pairing ◽  
Aromatic Molecules ◽  
Reaction Entropy

Ion Pairing and Dielectric Decrement in Glycosaminoglycan Brushes

2020 ◽  
Author(s):  
James Sterling ◽  
Wenjuan Jiang ◽  
Wesley M. Botello-Smith ◽  
Yun L. Luo
Keyword(s):  
Molecular Dynamics ◽  
Ion Pairs ◽  
Mean Field ◽  
Salt Bridge ◽  
Ion Pairing ◽  
Donnan Potential ◽  
Mean Field Models ◽  
Ion Exclusion ◽  
Dynamics Simulations ◽  
Contact Ion Pairs

Molecular dynamics simulations of hyaluronic acid and heparin brushes are presented that show important effects of ion-pairing, water dielectric decrease, and co-ion exclusion. Results show equilibria with electroneutrality attained through screening and pairing of brush anionic charges by cations. Most surprising is the reversal of the Donnan potential that would be expected based on electrostatic Boltzmann partitioning alone. Water dielectric decrement within the brush domain is also associated with Born hydration-driven cation exclusion from the brush. We observe that the primary partition energy attracting cations to attain brush electroneutrality is the ion-pairing or salt-bridge energy associated with cation-sulfate and cation-carboxylate solvent-separated and contact ion pairs. Potassium and sodium pairing to glycosaminoglycan carboxylates and sulfates consistently show similar abundance of contact-pairing and solvent-separated pairing. In these crowded macromolecular brushes, ion-pairing, Born-hydration, and electrostatic potential energies all contribute to attain electroneutrality and should therefore contribute in mean-field models to accurately represent brush electrostatics.

Graphene and Graphene Oxide Applications for SERS Sensing and Imaging

2019 ◽  
Vol 26 (38) ◽  
pp. 6878-6895 ◽  
Author(s):  
Anna Jabłońska ◽  
Aleksandra Jaworska ◽  
Mateusz Kasztelan ◽  
Sylwia Berbeć ◽  
Barbara Pałys
Keyword(s):  
Graphene Oxide ◽  
Surface Enhanced Raman Spectroscopy ◽  
Biological Species ◽  
Chemical Mechanism ◽  
Aromatic Molecules ◽  
Sers Enhancement ◽  
Reduced Graphene ◽  
Surface Enhanced Raman ◽  
Active Nanoparticles ◽  
Fluorescence Quencher

: Surface Enhanced Raman Spectroscopy (SERS) has a long history as an ultrasensitive platform for the detection of biological species from small aromatic molecules to complex biological systems as circulating tumor cells. Thanks to unique properties of graphene, the range of SERS applications has largely expanded. Graphene is efficient fluorescence quencher improving quality of Raman spectra. It contributes also to the SERS enhancement factor through the chemical mechanism. In turn, the chemical flexibility of Reduced Graphene Oxide (RGO) enables tunable adsorption of molecules or cells on SERS active surfaces. Graphene oxide composites with SERS active nanoparticles have been also applied for Raman imaging of cells. This review presents a survey of SERS assays employing graphene or RGO emphasizing the improvement of SERS enhancement brought by graphene or RGO. The structure and physical properties of graphene and RGO will be discussed too.

scholarly journals The carbonization of aromatic molecules with three-dimensional structures affords carbon materials with controlled pore sizes at the Ångstrom-level

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Tomoki Ogoshi ◽  
Yuma Sakatsume ◽  
Katsuto Onishi ◽  
Rui Tang ◽  
Kazuma Takahashi ◽  
...  
Keyword(s):  
Porous Carbon ◽  
Carbon Materials ◽  
Carbon Sources ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Thermal Polymerization ◽  
Sodium Ion Battery ◽  
Pore Sizes ◽  
Aromatic Molecules ◽  
Template Methods

AbstractCarbon materials with controlled pore sizes at the nanometer level have been obtained by template methods, chemical vapor desorption, and extraction of metals from carbides. However, to produce porous carbons with controlled pore sizes at the Ångstrom-level, syntheses that are simple, versatile, and reproducible are desired. Here, we report a synthetic method to prepare porous carbon materials with pore sizes that can be precisely controlled at the Ångstrom-level. Heating first induces thermal polymerization of selected three-dimensional aromatic molecules as the carbon sources, further heating results in extremely high carbonization yields (>86%). The porous carbon obtained from a tetrabiphenylmethane structure has a larger pore size (4.40 Å) than those from a spirobifluorene (4.07 Å) or a tetraphenylmethane precursor (4.05 Å). The porous carbon obtained from tetraphenylmethane is applied as an anode material for sodium-ion battery.

Photoisomerization-induced patterning of ion-pairing materials based on anionic azobenzene and its complex with a fluorescent π-electronic system

2021 ◽  
Vol 57 (35) ◽  
pp. 4287-4290
Author(s):  
Ryohei Yamakado ◽  
Issei Kitamura ◽  
Mitsuo Hara ◽  
Shusaku Nagano ◽  
Takahiro Seki ◽  
...  
Keyword(s):  
Surface Tension ◽  
Mass Transport ◽  
Trace Amount ◽  
Ion Pairs ◽  
Ion Pairing ◽  
Electronic System ◽  
Large Mass ◽  
System P ◽  
The Difference

Large mass transport driven by the difference in the photoisomerization-induced surface tension was demonstrated in ion pairs, enabling fluorescence patterning using a trace amount of photoisomerized anions in complexation with a π-electronic system.

Pyrrole-bridged quinones: π-electronic systems that modulate electronic structures by tautomerism and deprotonation

2021 ◽  
Author(s):  
Shinya Sugiura ◽  
Hiromitsu Maeda
Keyword(s):  
Infrared Absorption ◽  
Electronic Structures ◽  
Near Infrared ◽  
Ion Pairing ◽  
Anion Binding ◽  
Electronic Systems

A new series of π-extended quinone derivatives containing a pyrrole bridge exhibited NH/OH-type tautomerization and anion binding along with deprotonation that induced near-infrared absorption and ion-pairing assemblies.

Fluorescence from 3,5-diphenyl-8-CF3-BODIPYs with amino substituents on the phenyl rings: Quenching by aromatic molecules

2021 ◽  
Vol 254 ◽  
pp. 119632
Author(s):  
A.V. Gadomska ◽  
A.V. Nevidimov ◽  
S.A. Tovstun ◽  
O.V. Petrova ◽  
L.N. Sobenina ◽  
...  
Keyword(s):  
Aromatic Molecules ◽  
Phenyl Rings

scholarly journals Synthetic, Spectroscopic, Structural, and Electrochemical Investigations of Ferricenium Derivatives with Weakly Coordinating Anions: Ion Pairing, Substituent, and Solvent Effects

2021 ◽  
Author(s):  
Firoz Shah Tuglak Khan ◽  
Amy L Waldbusser ◽  
Maria C. C. Carrasco ◽  
Hadi Pourhadi ◽  
Shabnam Hematian
Keyword(s):  
Solvent Effects ◽  
Ion Pairing ◽  
Effective Strategy ◽  
Weakly Coordinating Anions ◽  
Weakly Coordinating ◽  
Electron Withdrawing Substituents

A facile and effective strategy for the preparation of a series of ferricenium complexes bearing either electron-donating or electron-withdrawing substituents with weakly coordinating anions such as [B(C6F5)4]– or SbF6– is...

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