Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/11/17 19:08:37」(JST)

wiki en

In chemistry, protonation is the addition of a proton (H⁺) to an atom, molecule, or ion, forming the conjugate acid.^[1] Some examples include

the protonation of water by sulfuric acid:

the protonation of isobutene in the formation of a carbocation:

=

the protonation of ammonia in the formation of ammonium chloride from ammonia and hydrogen chloride:

Protonation is a fundamental chemical reaction and is a step in many stoichiometric and catalytic processes. Some ions and molecules can undergo more than one protonation and are labeled polybasic, which is true of many biological macromolecules. Protonation and deprotonation occur in most acid-base reactions; they are the core of most acid-base reaction theories. A Bronsted-Lowry acid is defined as a chemical substance that protonates another substance. Upon protonating a substrate, the mass and the charge of the species each increase by one unit. Protonating or deprotonating a molecule or ion alters many chemical properties beyond the change in the charge and mass: hydrophilicity, reduction potential, optical properties, among others. Protonation is also an essential step in certain analytical procedures such as electrospray mass spectrometry.

Rates of protonation and deprotonation

Protonations are often rapid, in part because of the high mobility of protons in many solvent. The rate of protonation is related to the acidity of the protonating species, in that protonation by weak acids is slower than protonation of the same base by strong acids. The rates of protonation and deprotonation can be especially slow when protonation induces significant structural changes.^[2]

Reversibility and catalysis

Usually, protonations are reversible and the conjugate base is unchanged by being protonated. In some cases protonation induces isomerization, however. Cis-alkenes can be converted to trans-alkenes using a catalytic amount of protonating agent. Many enzymes, such as the serine hydrolases, operate by mechanisms that involve reversible protonations of substrates.

References

^ Zumdahl, S. S. “Chemistry” Heath, 1986: Lexington, MA. ISBN 0-669--04529-2.
^ Kramarz, K. W.; Norton, J. R. (1994). "Slow Proton Transfer Reactions in Organometallic and Bioinorganic Chemistry". Progress in Inorganic Chemistry 42: 1–65. doi:10.1002/9780470166437.ch1.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. メタノールおよびエチレングリコール中毒 methanol and ethylene glycol poisoning

English Journal

Fluorescent imaging of acidic compartments in living cells with a high selective novel one-photon ratiometric and two-photon acidic pH probe.

Miao F, Song G, Sun Y, Liu Y, Guo F, Zhang W, Tian M, Yu X.SourceCenter of Bio & Micro/Nano Functional Materials, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, PR China.
Biosensors & bioelectronics.Biosens Bioelectron.2013 Dec 15;50:42-9. doi: 10.1016/j.bios.2013.05.060. Epub 2013 Jun 18.
Fluorescent imaging of acidic compartments in living cells was carried out successfully by a novel molecule (CAE) that contained a pyridine unit and a carbazole core. As the protonation of the pyridine N atom of CAE, pH-dependent absorption and fluorescence properties were shown with a pKa of 5.47 w
PMID 23835215

Micellization of true amphoteric surfactants.

Li Y, Holmberg K, Bordes R.SourceChalmers University of Technology, Department of Chemical and Biological Engineering, Applied Surface Chemistry, SE-412 96 Göteborg, Sweden.
Journal of colloid and interface science.J Colloid Interface Sci.2013 Dec 1;411:47-52. doi: 10.1016/j.jcis.2013.08.048. Epub 2013 Sep 10.
The physical chemical behavior of a series of N-alkyl amino acid-based surfactants has been investigated. The series comprises four different types of amino acids as polar headgroups: glycine, aminomalonic acid, aspartic acid and glutamic acid, and for each type three homologues were synthesized: th
PMID 24112839

Fast assembly of non-thiolated DNA on gold surface at lower pH.

Jiang H, Materon EM, Sotomayor Mdel P, Liu J.SourceState Key Laboratory of Bioelectronics, Southeast University, 2 Sipailou, Nanjing 210096, PR China.
Journal of colloid and interface science.J Colloid Interface Sci.2013 Dec 1;411:92-7. doi: 10.1016/j.jcis.2013.08.043. Epub 2013 Sep 3.
In a typical protocol for attaching DNA to a gold electrode, thiolated DNA is incubated with the electrode at neutral pH overnight. Here we report fast adsorption of non-thiolated DNA oligomers on gold electrodes at acidic pH (i.e., pH ∼3.0). The peak-to-peak potential difference and the redox pea
PMID 24050641

Japanese Journal

A 2,2'-Bipyridine Dipalladium(II) Coordination System That Shows Three Different Coordination Modes of 3-Aminopropanethiol on Deprotonation

Kouno Masahiro,Miyashita Yoshitaro,Yoshinari Nobuto,Konno Takumi
Chemistry Letters advpub(0), 2015
… It was found that Hapt can adopt three different coordination modes (Hapt-κ2S, apt-κN,κ2S, H–1apt-κ2N,κ2S) dependent on its protonation states in this coordination system. …
NAID 130005094014

Creation of Kinetically Stabilized Porphyrin Microfilms through Synchronized Hydrogen-bonding Interactions in Microflow

Numata Munenori,Nishino Yuri,Sanada Yusuke,Sakurai Kazuo
Chemistry Letters 44(6), 861-863, 2015
… Fine hydrogen-bonded networks over the micrometer scale were spontaneously constructed in microflow through the synchronized protonation of porphyrin having four carboxylic acid groups. …
NAID 130005074588

Effect of Protonation on the Single-molecule-magnet Behavior of a Mixed (Phthalocyaninato)(porphyrinato)terbium Double-decker Complex

Tanaka Daisuke,Sumitani Nobuto,Inose Tomoko,Tanaka Hirofumi,Ishikawa Naoto,Ogawa Takuji
Chemistry Letters 44(5), 668-670, 2015
The crystal structure of a protonated phthalocyaninato–porphyrinato Tb(III) double-decker complex, [Tb(TPP)(HPc)] (1) (TPP: 5,10,15,20-tetraphenylporphyrin, Pc: phthalocyanine), was determined. Crysta …
NAID 130005067974