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.

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.

Tracing absorption and emission characteristics of halogen-bonded ion pairs involving halogenated imidazolium species

2021 ◽  
Vol 23 (12) ◽  
pp. 7480-7494
Author(s):  
Sarah Karbalaei Khani ◽  
Bastian Geissler ◽  
Elric Engelage ◽  
Patrick Nuernberger ◽  
Christof Hättig
Keyword(s):  
Ion Pairs ◽  
Ion Pairing ◽  
Emission Characteristics ◽  
Absorption And Emission ◽  
Spectroscopic Signatures

Spectroscopic signatures of ion-pairing are identified by variation of counterion and substitution and comparison with theory.

Electric condensation of divalent counterions by humic acid nanoparticles

2016 ◽  
Vol 13 (1) ◽  
pp. 76 ◽  
Author(s):  
Herman P. van Leeuwen ◽  
Raewyn M. Town
Keyword(s):  
Humic Acid ◽  
Charge Density ◽  
Double Layer ◽  
Ion Pairs ◽  
Ion Pairing ◽  
Counterion Condensation ◽  
Counterion Binding ◽  
Satisfactory Description ◽  
Poisson Boltzmann ◽  
Very High

Environmental context Humic acids are negatively charged soft nanoparticles that play a governing role in the speciation of many ionic and molecular compounds in the environment. The charge density in the humic acid nanoparticle can be very high and the binding of divalent cations such as Ca2+ appears to go far beyond traditional ion pairing or Poisson–Boltzmann electrostatics. A two-state approach, combining counterion condensation in the intraparticulate double layer and classical Donnan partitioning in the bulk of the particle, provides a satisfactory description of the physicochemical speciation. Abstract Experimental data for divalent counterion binding by soil humic acid nanoparticles are set against ion distributions as ensuing from continuous Poisson–Boltzmann electrostatics and a two-state condensation approach. The results demonstrate that Poisson–Boltzmann massively underestimates the extent of binding of Ca2+ by humic acid, and that electric condensation of these counterions within the soft nanoparticulate body must be involved. The measured stability of the Ca2+–humic acid associate is also much greater than that predicted for ion pairing between single Ca2+ ions and monovalent negative humic acid sites, which also points to extensive electrostatic cooperativity within the humic acid particle. At sufficiently high pH, the charge density inside the humic acid entity may indeed become so high that the bulk particle attains a very high and practically flat potential profile throughout. At this limit, all the intraparticulate Ca2+ is at approximately the same electrostatic potential and the status of individual ion pairs has become immaterial. A two-state model, combining counterion condensation in the charged intraparticulate part of the double layer at the particle–medium interface and Donnan partitioning in the uncharged bulk of the humic acid particle, seems to lead the way to adequate modelling of the divalent counterion binding for various particle sizes and different ionic strengths.

Elektronentransfer und Ionenpaare, 15 [ 1– 3] Radikalanion und Radikal-Kontakt-Ionenpaare von Dimesityl-tetraketon / Electron Transfer and Ion Pairing, 15 [1-3] Radical Anion and Radical Ion Pairs of Dimesityl Tetraketone

1990 ◽  
Vol 45 (8) ◽  
pp. 1197-1204 ◽  
Author(s):  
H. Bock ◽  
P. Hänel ◽  
H.-F. Herrmann
Keyword(s):  
Electron Transfer ◽  
Radical Anion ◽  
Ion Pairs ◽  
Ion Pairing ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Temperature Dependent ◽  
Contact Ion Pairs

The radical anion of dimesityltetraketone (ERed, I = -0.40 V) is easily generated in THF by potassium mirror/[2.2.2]-cryptand reduction. Its contact ion pairs with Na⊕, Cs⊕ and Ba⊕⊕ counter cations, prepared in THF solution by single electron transfer from the respective metals, are characterized by their ESR/ENDOR spectra, which exhibit temperature-dependent metal couplings of aNa⊕ = 0.061 mT (190 K), aCs⊕ = 0.021 mT (190 K), and aBa⊕⊕ = 0.145 mT (295 K).

scholarly journals First decade of π-electronic ion-pairing assemblies

2020 ◽  
Vol 5 (4) ◽  
pp. 757-771
Author(s):  
Yohei Haketa ◽  
Kazuki Urakawa ◽  
Hiromitsu Maeda
Keyword(s):  
Liquid Crystals ◽  
Ion Pairs ◽  
Ion Pairing

The prologue and progress of π-electronic ion-pairing assemblies, including synthesis of π-electronic ions, preparation of ion pairs, fabrication of assemblies as crystals, gels and liquid crystals and their characteristic properties, are summarized.

Absorption of 2,4-D, Dicamba, and Glyphosate by Excised Honeyvine Milkweed (Cynanchum Laeve) Leaves

Weed Science ◽  
1983 ◽  
Vol 31 (2) ◽  
pp. 271-274 ◽  
Author(s):  
John K. Soteres ◽  
Don S. Murray ◽  
Eddie Basler
Keyword(s):  
Surface Tension ◽  
Soil Conditions ◽  
Leaf Position ◽  
Drying Time ◽  
Leaf Surfaces ◽  
Anisic Acid ◽  
Dry Soil ◽  
The Difference ◽  
Dichlorophenoxy Acetic Acid ◽  
Reduced Surface

Absorption of 2,4-D [(2,4-dichlorophenoxy) acetic acid], dicamba [3,6-dichloro-o-anisic acid], and the isopropylamine salt of glyphosate [N-(phosphonomethyl) glycine] by excised honeyvine milkweed [Cynanchum laeve(Michx.) Pers.] leaves was determined. Experimental variables included leaf position (terminal vs. basal), a surfactant, 4-isopropenyl-1-methylcyclohexane plus unspecified emulsifiers (SA-77), and leaf collection dates. Absorption of the three herbicides by terminal and basal leaves was increased by the addition of the surfactant. However, the surfactant increased absorption into basal leaves more than into terminal leaves. The surfactant reduced surface tension and increased drying time of water droplets on adaxial leaf surfaces by 50%. The pH of the herbicide solutions was reduced from about 5.8 to about 3.9 by SA-77. Absorption of all three herbicides was greater into terminal than into basal leaves when the surfactant was not present, but the difference disappeared when the surfactant was added. Generally, no differences were observed in the absorption of 2,4-D and dicamba. Glyphosate absorption was greater in terminal leaves collected after a period of adequate moisture than after a period of dry soil conditions.

scholarly journals Mass Transport of Gases across the Air–Water Interface: Implications for Aldehyde Emissions in the Uinta Basin, Utah, USA

Atmosphere ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1057
Author(s):  
Marc L. Mansfield
Keyword(s):  
Mass Transport ◽  
Vapor Phase ◽  
Current Model ◽  
Molecular Forms ◽  
Water Interface ◽  
Uinta Basin ◽  
Transport Models ◽  
Air Water Interface ◽  
The Difference ◽  
Pass Through

When they dissolve in water, aldehydes become hydrated to gem-diols: R−COH+H2O↔RCH(OH)2. Such reactions can complicate air–water transport models. Because of a persistent belief that the gem-diols do not exist in the vapor phase, typical models do not allow them to pass through the air–water interface, but in fact, they do. Therefore, transport models that allow both molecular forms to exist in both phases and to pass through the interface are needed. Such a model is presented here as a generalization of Whitman’s two-film model. Since Whitman’s model has fallen into disuse, justification of its use is also given. There are hypothetical instances for which the flux predicted by the current model is significantly larger than the flux predicted when models forbid the diol form from passing through the interface. However, for formaldehyde and acetaldehyde, the difference is about 6% and 2%, respectively.

scholarly journals Hydroxide promotes ion pairing in the NaNO2–NaOH–H2O system

2021 ◽  
Vol 23 (1) ◽  
pp. 112-122
Author(s):  
Trent R. Graham ◽  
Mateusz Dembowski ◽  
Hsiu-Wen Wang ◽  
Sebastian T. Mergelsberg ◽  
Emily T. Nienhuis ◽  
...  
Keyword(s):  
Sodium Hydroxide ◽  
Sodium Nitrite ◽  
Ion Pairing ◽  
System P ◽  
Insight Into

The solubility and spectroscopy of sodium nitrite in sodium hydroxide solutions are detailed to provide insight into processes underlying solubility.

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