Trimethylammonium Ions Research Articles

A proton magnetic resonance investigation of solid mono-, di-, tri- and tetra-methylammonium chlorides

The proton magnetic resonance spectrum has been measured over a wide temperature range for polycrystalline mono-, di-, tri-, and tetramethylammoniumn chlorides, which are found to exhibit a diversity of ionic motions. Only the dimethylammonium ion exhibits spectral narrowing by rotational tunnelling of the methyl groups at 4°K. At higher temperatures the other three ions exhibit methyl group reorientation. The monomethylammonium ion also shows reorientation of the N +H 3 group, the dimethylammonium ion reorients about its diad axis, and the trimethylammonium ion about its triad axis. The tetramethylammonium ion exhibits quasi-isotropic reorientation. None of the compounds shows diffusional narrowing at the highest temperatures of measurement.

Rate and equilibrium constants for each step in the reaction of trimethylammonium ions with formaldehyde to give formocholine cations in aqueous solution

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRate and equilibrium constants for each step in the reaction of trimethylammonium ions with formaldehyde to give formocholine cations in aqueous solutionJack Hine and Fritz C. KokeshCite this: J. Am. Chem. Soc. 1970, 92, 14, 4383–4388Publication Date (Print):July 1, 1970Publication History Published online1 May 2002Published inissue 1 July 1970https://doi.org/10.1021/ja00717a040RIGHTS & PERMISSIONSArticle Views196Altmetric-Citations12LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (746 KB) Get e-Alerts Get e-Alerts

Proton transfer in methylammonium salts: a comparison of water and acetonitrile as solvents

The rate of deprotonation of trimethylammonium ion by its conjugate base is 103 smaller in acetonitrile than in water.

Intermolecular Interaction in Montmorillonites: NH-Co Systems

AbstractThe mechanism of interaction between cationic organic molecules satisfying exchange sites in montmorillonite and organic molecules with carbonyl groups was investigated. Dialkyl amides adsorbed on trimethyl-ammonium- and tetramethylammonium-montmorillonite were studied by i.r. spectroscopy. The electronegativity or basicity of the amides, expressed as a summation of the Taft polar factors (Σσ*), was found to be linearly related to the C-O stretching frequency after adsorption on trimethyl-ammonium-montmorillonite. Furthermore, the changes in the C—O and N—H stretching frequencies of the amides and trimethylammonium ion respectively, exhibited a direct linear relationship. Thus, the dialkyl amides were shown to be hydrogen bonded through the oxygen of the carbonyl group to the hydrogen of the trimethylammonium. The (001) spacing of trimethyl-ammonium-montmorillonite was 12·9 Å Only after the adsorption of amide molecules of the size of N,N-diethylacetamide or larger did this spacing change. Dialkyl amides were adsorbed on tetramethylammonium-montmorillonite, but less energetically than on trimethylammonium-clay. The (001) spacing of tetramethylammonium-montmorillonite was 13·8 Å and remained the same after adsorption of the dialkyl amides. Evidence of hydrogen bonding between the hydrogen of trimethylammonium-ion and some other carbonyl compounds was also noted.

Kinetics of proton exchange of trimethylammonium ion by NMR: A laboratory experiment

In this experiment several plausible reactions for the hydration of pyruvic acid are suggested and the student makes use of the data collected to select the most probable ones.

Effects of Magnesium Ions, Adenosine Triphosphate, Palmitoylcarnitine, and Palmitoyl Coenzyme A on Acetyl Coenzyme A Carboxylase

Acetyl coenzyme A carboxylase is activated strongly by incubation with magnesium ions in the absence of citrate and by incubation with citrate in the absence of magnesium ions. The activation by magnesium ions is concentration- and time-dependent. Under optimum conditions the effects of citrate and magnesium ions are not additive. Although the activation by magnesium ions occurs in the absence of citrate, the enzyme requires citrate for the complete reaction. Addition of adenosine triphosphate to the activation medium containing either magnesium ions or citrate or both strongly inhibits the activation of acetyl coenzyme A carboxylase. The inhibition is not due to removal of magnesium ions by chelation with adenosine triphosphate. Enzyme which has been activated with magnesium ions sediments at about the same rate as the inactive enzyme. Palmitoyl carnitine and cetyl trimethylammonium ions also stimulate the activity of the enzyme. This type of activation occurs rapidly, unlike the activation of the rat liver enzyme by magnesium ions and citrate. The maximum degree of stimulation by palmitoyl carnitine is observed when acetyl coenzyme A carboxylase has not been fully activated with other activators, but a 2- to 3-fold stimulation is observed even with enzyme which has been activated optimally with magnesium ions and citrate.

Proton exchange between ammonium ion, trimethyl-ammonium ion, and water. Speed of the dehydration step that precedes bimolecular proton transfer

Proton exchange between ammonium ion, trimethyl-ammonium ion, and water. Speed of the dehydration step that precedes bimolecular proton transfer

The Effect of Univalent Cation Salts on the Stability and on Certain Physical Properties of Pyruvate Kinase

Abstract The effects of a series of univalent cation salts on certain properties of pyruvate kinase, including sedimentation behavior, perturbation of tryptophan residues, and stability of the enzyme, have been investigated. Ultraviolet difference spectra of pyruvate kinase in 0.1 m solutions of activator univalent cation chlorides (K+, NH4+, or Na+) in comparison with enzyme in 0.1 m nonactivator univalent cation chlorides (Li+, or trimethylammonium ion, or tris(hydroxymethyl)aminomethane cation) were determined. Tryptophanyl difference spectra with absorbance peaks at 286 mµ and 295 mµ were obtained under these conditions only when the nonactivator cation Tris+ was included in the experiment. Difference spectra of pyruvate kinase in 0.1 m KCl versus enzyme in 0.1 m LiCl with or without various substrates and Mg++ in the reaction showed no absorbance differences characteristic of the perturbation of tryptophan residues. In contrast, different comparisons of univalent cation chlorides at concentrations of 0.5 to 0.86 m showed capacities to perturb tryptophan residues of pyruvate kinase that were inversely correlated with the known capacities of univalent cations to activate the enzyme. A study of the stability of pyruvate kinase in a series of univalent cation salt solutions showed a positive correlation between the capacities of cations to protect against inactivation and known capacities to activate. In addition to the effect of univalent cations, different anion species influenced the extent of perturbation of tryptophan residues and the stability of the enzyme. The perturbation of the tryptophan residues in the presence of Tris+ (cation) was inhibited by the addition of multivalent anions, phosphate, arsenate, and sulfate. Also, the enzyme consistently showed greater stability in buffer solutions containing the multivalent anions phosphate, arsenate, or sulfate than in buffer solutions in which the predominant anions were acetate, chloride, or nitrate. The sedimentation behavior of pyruvate kinase in the ultracentrifuge was not greatly affected by type of univalent cation salt in the environment, with the exception that the s020,w value was lower in a solution of Tris-Cl than in other salts.

Rate constants for deuterium exchange of trimethylammonium ion in heavy water.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRate constants for deuterium exchange of trimethylammonium ion in heavy waterRobert J. Day and Charles N. ReilleyCite this: J. Phys. Chem. 1967, 71, 6, 1588–1595Publication Date (Print):May 1, 1967Publication History Published online1 May 2002Published inissue 1 May 1967https://doi.org/10.1021/j100865a007RIGHTS & PERMISSIONSArticle Views61Altmetric-Citations6LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (808 KB) Get e-Alerts

A nuclear magnetic resonance study of acid dissociation and proton exchange of trimethylammonium ion in methanol

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA nuclear magnetic resonance study of acid dissociation and proton exchange of trimethylammonium ion in methanolErnest GrunwaldCite this: J. Phys. Chem. 1967, 71, 6, 1846–1850Publication Date (Print):May 1, 1967Publication History Published online1 May 2002Published inissue 1 May 1967https://doi.org/10.1021/j100865a048RIGHTS & PERMISSIONSArticle Views43Altmetric-Citations6LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (462 KB) Get e-Alerts

Polar group orientation and the electrical properties of lecithin bimolecular leaflets

The first part of this paper is concerned primarily with the question of whether the phosphate and trimethylammonium ions in the head groups of a lecithin bimolecular leaflet are oriented in lines normal to, or in a plane parallel to the leaflet. This problem has been approached by comparing the measured electrokinetic potentials with those to be expected theoretically from these two orientations. In order to calculate the potentials the equations have been derived for parallel sheets of fixed positive and negative charges freely perfused by an aqueous solution of univalent ions. It has been concluded, from comparison of the theoretical and measured electrokinetic potentials that the phosphate and trimethylammonium groups are in a plane parallel to the leaflet. In the second part of the paper the frequency dependence of the capacitance of the lecithin bimolecular leaflet in aqueous solution has been considered in terms of a three-phase dielectric, i.e. layers of hydrocarbon, phosphatidyl chorine and aqueous solution. Previously obtained experimental results have been extended to show that between approximately 5 × 10 −3 and 10 7 c/s the capacitance of the leaflet is constant. Taking into consideration the polar group orientation deduced from the first part of this paper, probable values for the capacitance and conductance of the phosphatidyl choline layer were estimated. Substitution of these values into the electrical equations for the three phase dielectric gives capacitances and conductances for the whole system which are consistent with the observed results. It is concluded that the capacitance and conductance (measured normal to their surfaces) of the lecithin leaflets are controlled almost entirely by the hydrocarbon region and that the polar groups make a negligible contribution.

Nuclear Magnetic Resonance Study of the Protolysis of Trimethylammonium Ion in Aqueous Solution—Order of the Reaction with Respect to Solvent

It was found previously that the proton-transfer reaction between trimethylammonium ion and trimethylamine in aqueous solution takes place via water. In the present investigation the number of water molecules involved in this reaction was determined. Proton exchange rates were determined from NMR measurements in trimethylamine—trimethylammonium chloride buffer solutions in O17-enriched water. It is concluded that one water molecule is involved in the transfer reaction. In the appendix, theoretical equations are derived for the dependence of the observed spin-echo decay rate on the 180° pulse rate for the case of fast exchange.

Boron Hydrides. IV. Concerning the Geometry of the Activated Complex in the Hydrolysis of Borohydride Ion by Trimethylammonium Ion

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBoron Hydrides. IV. Concerning the Geometry of the Activated Complex in the Hydrolysis of Borohydride Ion by Trimethylammonium IonRobert Earl. DavisCite this: J. Am. Chem. Soc. 1962, 84, 6, 892–894Publication Date (Print):March 1, 1962Publication History Published online1 May 2002Published inissue 1 March 1962https://doi.org/10.1021/ja00865a002RIGHTS & PERMISSIONSArticle Views120Altmetric-Citations23LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (371 KB) Get e-Alerts Get e-Alerts

Rates and Mechanisms of Protolysis of Di- and Trimethylammonium Ions Studied by Proton Magnetic Resonance

A kinetic analysis of the protolysis reactions of di- and trimethylammonium ions in aqueous solution has been carried out using the nuclear magnetic resonance technique. The results complement those of a similar study of methylammonium ion reported on in an earlier paper. In the pH range studied (between 3 and 5) the main mechanism is: RNH++RN⇆RN+RNH+. The reaction involves water in nearly every exchange. The measured rate constants are: 6.0×108 and 3.1×108 sec—1M—1 for di- and trimethylammonium, respectively.

The Overpotential of the Manganese Dioxide Electrode

The overpotential of electrodeposited electrodes can be measured with fair reproducibility. Overpotential is a linear function of the logarithm of the ammonium ion concentration, at constant pH, but not of the logarithm of the apparent current density. It varies much less with the hydrogen ion than with the ammonium ion concentration. When ammonium ion in the electrolyte is replaced by methylammonium, dimethylammonium, or trimethylammonium ion the overpotential is increased. The change of overpotential with temperature was measured. The bearing of the results on the theory of the discharge mechanism is considered.

Mechanism of hydrolysis II. New evidence for an acylated enzyme as intermediate

Acetylcholinesterase catalyzes the hydrolysis of thiolacetic acid. The undissociated acid molecules are the direct reactants. The dissociation constant of the conjugate acid of the basic group of the enzyme calculated from the pH dependence of this reaction is about 3.10 −7. This reaction is very strong evidence that the enzyme catalyzes oxygen exchange between acids and water, a necessary condition for the correctness of the proposed theory of enzymic activity, involving an acylated enzyme as intermediate. Trimethylammonium ion and 1:10-decane bis(trimethylammonium) bromide even in enormous excess only partially inhibit the reaction, whereas ethyl acetate hydrolysis is completely inhibited, thus indicating a spacial and functional separation of the anionic and esteratic enzyme sites. Prostigmine which reacts with both sites completely inhibits thiolacetic acid hydrolysis.