Synthesis and protonation studies of a meso-unsubstituted surfactant porphyrin

1985 ◽  
Vol 63 (9) ◽  
pp. 2420-2424 ◽  
Author(s):  
Michel Ringuet ◽  
Jacques Gagnon
Keyword(s):  
Chloroform Solution ◽  
Spectroscopic Studies ◽  
Side Chain ◽  
Carboxyl Groups ◽  
Free Base ◽  
Base Form

A meso-unsubstituted surfactant porphyrin has been synthesized. Spectroscopic studies show that intermolecular protonation occurs between the side-chain carboxyl groups and the inner nitrogen atoms of the porphyrin, leading to the formation of a porphyrin dication. In 5 × 10−5 M chloroform solution, 27% of the porphyrin molecules are in the dicationic form and they are self-associated with some remaining molecules in the free base form.

Thermochromism of Metal Exchange Reaction between Zinc(II) and Mercury(II) Porphyrins

1995 ◽  
Vol 50 (4) ◽  
pp. 545-550 ◽  
Author(s):  
Masaaki Tabata ◽  
Masahiro Ide ◽  
Kentaro Kaneko
Keyword(s):  
Aqueous Solution ◽  
Exchange Reaction ◽  
Thermodynamic Parameters ◽  
Distribution Curve ◽  
Equilibrium Constants ◽  
Metal Exchange ◽  
Free Base ◽  
Temperature Range ◽  
Base Form ◽  
Metal Exchange Reaction

Thermochromism was observed for an aqueous solution containing zinc(II) and mercury( II) cations and N-p-nitrobenzyl-5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin anion (NO2Bz(Htpps)4-) in the temperature range 10 to 70 °C. The equilibrium constants and the thermodynamic parameters of Zn(NO2Bztpps)3- and Hg(NO2Bztpps)3- have been determined spectrophotometrically to elucidate the thermochromism at 10, 15, 20, 25 and 30 °C in 0.1 mol dm-3 NaNO3. The protonation and metalation constants of NO2Bz(Htpps)4- are defined as K2 = [H2P][H+]-1[HP]-1, K3 = [H3P][H+]-1[H2P]-1 and KMP = [M P][H+][M2+]-1[HP]-1, where HP and MP denote the free base form of the prophyrin and the metalloporphyrins of zinc(II) and mercury(II), respectively. Charges of the prophyrin and metalloporphyrins are omitted for simplicity. The following values were found: logK2 = 7.75 ±0.02 (25 °C), ΔH°/kJmol-1 = -21.2±0.5 and ΔS°/Jmol-1K-1 = 77±1, logK3 = 2.55±0.02 (25 °C), ΔH°/kJmol-1 = -25±0.8 and ΔS°/Jmol-1K-1 = -35±3 and log KZnP = 0.63±0.03 (25 °C), ΔH°/kJmol-1 = 31.0±0.8 and ΔS°/Jmol-1K-1 = 116±3, logKHgP = 6.22±0.03 (25 °C), ΔH°/kJmol-1 = 4.5±0.7 and ΔS°/Jmol-1K-1 = 134±2. The distribution curve calculated from the thermodynamic parameters sufficiently agrees with the observed metal exchange reaction between the metalloporphyrins.

scholarly journals Distribution of Methanol-Water and Ethanol-Water Mixtures in Strongly Basic Polystyrene Anion Exchangers in Free Base Form.

1962 ◽  
Vol 16 ◽  
pp. 392-402 ◽  
Author(s):  
Eero Sjöström ◽  
Lalli Nykänen ◽  
Pekka Laitinen ◽  
G. A. Sim ◽  
Olof Theander ◽  
...  
Keyword(s):  
Free Base ◽  
Anion Exchangers ◽  
Base Form

Na+/NH4+, Na+/H+ Exchanges and NH3 Movement Across the Gill of Carassius Auratus

1973 ◽  
Vol 58 (1) ◽  
pp. 255-275 ◽  
Author(s):  
J. MAETZ
Keyword(s):  
Carassius Auratus ◽  
External Medium ◽  
Ammonia Excretion ◽  
Alkaline Media ◽  
Ionic Balance ◽  
Free Base ◽  
Acid Media ◽  
Base Form ◽  
Monovalent Ions ◽  
The Law

1. Sodium exchange, ammonia excretion and H+ ion movement across the gill were measured in sodium-depleted Carassius auratus. Sodium uptake and ammonia excretion are considerably enhanced by sodium depletion. In this respect sodium-depleted fish behave as ammonia-loaded fish. 2. A decrease of the external pH by one unit results in a 50-60% decrease in both influx and efflux of sodium. A transient augmentation of the rate of ammonia excretion is observed upon acidification, suggesting an increased permeability of the gill to the free-base form of ammonia. 3. The ionic balance sheet of the movements of the monovalent ions across the gill was drawn up when a permeant co-ion for sodium was absent from the external medium. In both acid and alkaline media the ionic balance was achieved in accordance with the law of electroneutrality of external and internal solutions. 4. Net Na+ uptake was only found to be correlated to NH4+ excretion if H+ ion movements across the gill were taken into account. 5. Ammonia-gradient experiments were performed to test the ability of the gill to excrete ammonia against a gradient of ammonia partial pressure. Ammonia excretion is independent of this gradient in alkaline media when sodium ions are present. In these conditions ammonia moves in the ionic form. In acid media, with Na present in the external medium, ammonia movement is correlated with the pNH3 gradient but uphill movement still occurs. Ammonia moves in both the free-base and the ionized forms. In the absence of external sodium, movements of ammonia obey the law for passive transfer and ammonia moves exclusively in the free-base form, even though the external medium is alkaline.

scholarly journals Chiral Amphiphilic Secondary Amine-Porphyrin Hybrids for Aqueous Organocatalysis

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3420 ◽  
Author(s):  
Aitor Arlegui ◽  
Pol Torres ◽  
Victor Cuesta ◽  
Joaquim Crusats ◽  
Albert Moyano
Keyword(s):  
Catalytic Activity ◽  
High Yield ◽  
Aldol Reactions ◽  
Free Base ◽  
Reaction Products ◽  
Chirality Transfer ◽  
Base Form ◽  
Low Degree ◽  
Acidic Conditions ◽  
Ph Dependent

Two chiral proline-derived amphiphilic 5-substituted-10,15,20-tris(4-sulfonatophenyl)porphyrins were prepared, and their pH-dependent supramolecular behavior was studied. In neutral aqueous solutions, the free-base form of the hybrids is highly soluble, allowing enamine-based organocatalysis to take place, whereas under acidic conditions, the porphyrinic protonated core of the hybrid leads to the formation of self-assembled structures, so that the hybrids flocculate and their catalytic activity is fully suppressed. The low degree of chirality transfer observed for aqueous Michael and aldol reactions strongly suggests that these reactions take place under true “in water” organocatalytic conditions. The highly insoluble catalyst aggregates can easily be separated from the reaction products by centrifugation of the acidic reaction mixtures, and after neutralization and desalting, the sodium salts of the sulfonated amine-porphyrin hybrids, retaining their full catalytic activity, can be recovered in high yield.

Colorimetric assay for the rapid determination of free-base nicotine in e-liquid

2020 ◽  
Vol 12 (2) ◽  
pp. 193-199
Author(s):  
Yan-Jun Huang ◽  
Qi-Xin Deng ◽  
Hong-Qiao Lan ◽  
Zheng-Zhong Fang ◽  
Hui Chen ◽  
...  
Keyword(s):  
Rapid Determination ◽  
Colorimetric Assay ◽  
Water Soluble ◽  
Free Base ◽  
Base Form

Nicotine exists in e-liquids primarily as the monoprotonated form and free-base form. The free-base form could be evaluated by use of a water-soluble indicator.

LINGCOD MUSCLE NUCLEASE

1959 ◽  
Vol 37 (8) ◽  
pp. 945-952 ◽  
Author(s):  
Neil Tomlinson
Keyword(s):  
Ribonucleic Acid ◽  
Free Base ◽  
Ophiodon Elongatus ◽  
Base Form ◽  
Nitrophenyl Phosphate ◽  
Diethylaminoethyl Cellulose ◽  
Cyclic Phosphates ◽  
Low Rate

A nuclease from muscle of lingcod (Ophiodon elongatus) has been purified by chromatography on diethylaminoethyl cellulose in the free-base form by stepwise elution with increasing concentrations of tris(hydroxymethyl)aminomethane. HCl, pH 7.0. The nuclease has been shown to hydrolyze ribonucleic acid, adenosine 3′-benzyl phosphate, thymidine 3′-p-nitrophenyl phosphate, and thymidine 5′-p-nitrophenyl phosphate. The latter compound was hydrolyzed at a very low rate. It did not hydrolyze adenosine 2′- or 5′- benzyl phosphate or certain nucleoside cyclic phosphates. The enzyme was inhibited by monoiodoacetate but not by heparin.

scholarly journals The Heritage Structure of Sanskrit Compound in Old Javanese Language: A Contrastive Linguistics Study

2017 ◽  
Vol 1 (1) ◽  
pp. 44
Author(s):  
Ni Ketut Ratna Erawati ◽  
I Made Wijana
Keyword(s):  
Theoretical Basis ◽  
Compound Word ◽  
Free Base ◽  
Compound Words ◽  
Base Form ◽  
Methods And Techniques ◽  
Three Stages ◽  
Contrastive Linguistics ◽  
Object Of Study ◽  
Agglutinative Languages

Sanskrit and Old Javanese language are not cognate language. In a language comparative study, the language that has no geneologis relationship could be analyzed contrastively. In typological morphological, Sanskrit is classified into flective language, while the Old Javanese language is classified agglutinative languages. The aim of this writing is to describe and explain the grammatical process of Sanskrit compound word that orbed into Old Javanese. The data tabulation belonging to the compound words were analyzed explanative descriptively according to the nature of the data and the methods and techniques that relevant to the object of study. The methods and techniques used were framed into three stages, namely the data providing, data analysis, and presenting analysis. The theoretical basis of language comparison is similarity or semblance of form and meaning. Based on the analysis, the compound word in Old Javanese language largely derived from the Sanskrit in free base form or derivation form. The forms are borrowed intact and some are accompanied by grammatical processes in the Old Javanese. The similarity and resemblance of these forms are inherited as a loan. The Old Javanese compounding process has the structure: Sanskrit + Sanskrit, Sanskrit + Old Javanese, Old Javanese + Sanskrit. Grammatical processes that occurred are affixation appropriate rules of Old Javanese.

TERPENOIDS: I. THE CONSTITUTION AND STEREOCHEMISTRY OF CEANOTHIC ACID

1962 ◽  
Vol 40 (4) ◽  
pp. 788-795 ◽  
Author(s):  
P. De Mayo ◽  
A. N. Starratt
Keyword(s):  
Methyl Ester ◽  
Acid Methyl Ester ◽  
Spectroscopic Studies ◽  
Carboxyl Groups ◽  
Keto Ester ◽  
Acid Methyl

Ceanothic acid, a substance previously isolated by Julian, Pikl, and Dawson (J. Am. Chem. Soc. 60, 77 (1938)), has been shown to be a triterpenoid related to the lupeol–betulin group, but in which ring A is five-membered. It has been degraded to the keto ester A norbetulonic acid methyl ester, a substance of defined constitution and stereochemistry. The hydroxyl and carboxyl groups attached to ring A have been shown by spectroscopic studies to be trans, the stereochemistry of ceanothic acid being that represented by (XII).

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