On the effect of ion pairing of Keggin type polyanions with quaternary ammonium cations on redox potentials in organic solvents

2016 ◽  
Vol 18 (32) ◽  
pp. 22487-22493 ◽  
Author(s):  
Bo Chen ◽  
Ronny Neumann
Keyword(s):  
Electrochemical Properties ◽  
Organic Solvents ◽  
Quaternary Ammonium ◽  
Ion Pairing ◽  
Redox Potentials ◽  
Quaternary Ammonium Cations ◽  
Keggin Type

The electrochemical properties of polyoxometalates in organic solvents show an interrelation between redox potentials, solvents and ion pairing.

scholarly journals Rational Design of Molecularly Imprinted Polymers Using Quaternary Ammonium Cations for Glyphosate Detection

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 296
Author(s):  
Mashaalah Zarejousheghani ◽  
Alaa Jaafar ◽  
Hendrik Wollmerstaedt ◽  
Parvaneh Rahimi ◽  
Helko Borsdorf ◽  
...  
Keyword(s):  
Molecularly Imprinted Polymers ◽  
Quaternary Ammonium ◽  
Photoelectron Spectroscopy ◽  
Rational Design ◽  
Water Soluble ◽  
Trimethylammonium Chloride ◽  
Molecularly Imprinted ◽  
Functional Monomers ◽  
Imprinted Polymers ◽  
Quaternary Ammonium Cations

Molecularly imprinted polymers have emerged as cost-effective and rugged artificial selective sorbents for combination with different sensors. In this study, quaternary ammonium cations, as functional monomers, were systematically evaluated to design imprinted polymers for glyphosate as an important model compound for electrically charged and highly water-soluble chemical compounds. To this aim, a small pool of monomers were used including (3-acrylamidopropyl)trimethylammonium chloride, [2-(acryloyloxy)ethyl]trimethylammonium chloride, and diallyldimethylammonium chloride. The simultaneous interactions between three positively charged monomers and glyphosate were preliminary evaluated using statistical design of the experiment method. Afterwards, different polymers were synthesized at the gold surface of the quartz crystal microbalance sensor using optimized and not optimized glyphosate-monomers ratios. All synthesized polymers were characterized using atomic force microscopy, contact angle, Fourier-transform infrared, and X-ray photoelectron spectroscopy. Evaluated functional monomers showed promise as highly efficient functional monomers, when they are used together and at the optimized ratio, as predicted by the statistical method. Obtained results from the modified sensors were used to develop a simple model describing the binding characteristics at the surface of the different synthesized polymers. This model helps to develop new synthesis strategies for rational design of the highly selective imprinted polymers and to use as a sensing platform for water soluble and polar targets.

A Conformational Analysis of the Spirocyclic Quaternary Ammonium Cation [(CH2)4N(CH2)4]+ in its Bromide and Picrate Salts

2004 ◽  
Vol 59 (3) ◽  
pp. 259-263 ◽  
Author(s):  
Uwe Monkowius ◽  
Stefan Nogai ◽  
Hubert Schmidbaur
Keyword(s):  
Gas Phase ◽  
Quaternary Ammonium ◽  
Point Group ◽  
High Yield ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quaternary Ammonium Cations ◽  
Twist Conformation ◽  
Twist Form ◽  
Group D

High-yield syntheses of the bromide (1a) and picrate salts (1b) of the 5-azonia-spiro[4]nonane cation [(CH2)4N(CH2)4]+ are reported. In the single crystal X-ray diffraction analyses of the two salts the spirocyclic quaternary ammonium cations have their five-membered rings in envelop and twist conformations modified by packing forces. The conformation found experimentally for 1a has C2-symmetry as predicted for the gas phase by quantum-chemical calculations (RI-DFT, RI-MP2), but the five-membered rings are intermediate between the expected envelop and the twist form. For 1b, both of the two independent cations can be described as a combination of rings in an envelop and a twist conformation. According to the NMR spectra, in solution the cations are highly flexible and pseudosymmetrical (point group D2d)

scholarly journals The atypical cation-conduction and gating properties of ELIC underscore the marked functional versatility of the pentameric ligand-gated ion-channel fold

2015 ◽  
Vol 146 (1) ◽  
pp. 15-36 ◽  
Author(s):  
Giovanni Gonzalez-Gutierrez ◽  
Claudio Grosman
Keyword(s):  
Quaternary Ammonium ◽  
Time Course ◽  
Three Dimensional ◽  
Mouse Muscle ◽  
Current Decay ◽  
Quaternary Ammonium Cations ◽  
Inward Currents ◽  
Time Courses ◽  
Extracellular Side ◽  
Invariant Functional

The superfamily of pentameric ligand-gated ion channels (pLGICs) is unique among ionotropic receptors in that the same overall structure has evolved to generate multiple members with different combinations of agonist specificities and permeant-ion charge selectivities. However, aside from these differences, pLGICs have been typically regarded as having several invariant functional properties. These include pore blockade by extracellular quaternary-ammonium cations in the micromolar-to-millimolar concentration range (in the case of the cation-selective members), and a gain-of-function phenotype, which manifests as a slower deactivation time course, as a result of mutations that reduce the hydrophobicity of the transmembrane pore lining. Here, we tested this notion on three distantly related cation-selective members of the pLGIC superfamily: the mouse muscle nicotinic acetylcholine receptor (nAChR), and the bacterial GLIC and ELIC channels. Remarkably, we found that, whereas low millimolar concentrations of TMA+ and TEA+ block the nAChR and GLIC, neither of these two quaternary-ammonium cations blocks ELIC at such concentrations; instead, both carry measurable inward currents when present as the only cations on the extracellular side. Also, we found that, whereas lidocaine binding speeds up the current-decay time courses of the nAChR and GLIC in the presence of saturating concentrations of agonists, the binding of lidocaine to ELIC slows this time course down. Furthermore, whereas mutations that reduce the hydrophobicity of the side chains at position 9′ of the M2 α-helices greatly slowed the deactivation time course of the nAChR and GLIC, these mutations had little effect—or even sped up deactivation—when engineered in ELIC. Our data indicate that caution should be exercised when generalizing results obtained with ELIC to the rest of the pLGICs, but more intriguingly, they hint at the possibility that ELIC is a representative of a novel branch of the superfamily with markedly divergent pore properties despite a well-conserved three-dimensional architecture.

Mono- and tri-β-substituted unsymmetrical metalloporphyrins: synthesis, structural, spectral and electrochemical properties

RSC Advances ◽  
2015 ◽  
Vol 5 (82) ◽  
pp. 66824-66832 ◽  
Author(s):  
Kamal Prakash ◽  
Ravi Kumar ◽  
Muniappan Sankar
Keyword(s):  
Electrochemical Properties ◽  
Dramatic Reduction ◽  
Redox Potentials ◽  
Electrochemical Redox ◽  
Spectral And Electrochemical Properties ◽  
Homo Lumo

Mono-/tri-β-substituted metalloporphyrins have been synthesized and characterized. Dramatic reduction in the HOMO–LUMO gap with tunable electronic, spectral and electrochemical redox potentials were observed as the number of electron withdrawing groups increased.

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