Aqueous trifluoroacetic acid as a medium for organic reactions. I. Acidity functions and the identity of the manganese(VII) species found in powerfully acidic media

1976 ◽  
Vol 54 (3) ◽  
pp. 440-447 ◽  
Author(s):  
Udo A. Spitzer ◽  
Trevor W. Toone ◽  
Ross Stewart
Keyword(s):  
Trifluoroacetic Acid ◽  
Water System ◽  
Visible Spectrum ◽  
Pair Formation ◽  
Acidity Function ◽  
Acidic Media ◽  
Uv Visible ◽  
Acidity Functions ◽  
Trifluoroacetate Complex

The HR acidity function has been determined for the trifluoroacetic acid–water system, and extended beyond 100% acid by the addition of trifluoroacetic anhydride, to 99.5 wt.% anhydride. The existing H0 acidity function is corrected and extended to 100% trifluoroacetic acid, confirming Eaborn's observation that H0 attains a minimum value at approximately 97% acid. Comparison of the acidity functions shows that although trifluoroacetic acid is only weakly protonating, it is a strongly protonating-dehydrating medium. Changes in the uv–visible spectrum of potassium permanganate produced by changing acid concentration are used to calculate the degree of further ionization of the permanganate ion; the correlation of this with the HR acidity function further suggests the presence of the permanganyl cation, MnO3+, or its trifluoroacetate complex or ester, MnO3•O2CCF3, in these solutions. A cryoscopic investigation into the mode of ionization of permanganate in trifluoroacetic acid reveals that extensive ion-pair formation occurs in this solvent. Although this effect prevents an unequivocal determination of the number of solute particles being made the results are consistent with the presence of a permanganyl species in solution.

scholarly journals Antibacterial Activity of CuO Nanoparticles Synthesized by Justicia adhatoda Leaf Extract

2021 ◽  
pp. 160-170
Author(s):  
S. Alwin David ◽  
P. Subramanian
Keyword(s):  
Antibacterial Activity ◽  
Leaf Extract ◽  
Visible Spectrum ◽  
Cuo Nanoparticles ◽  
Design Synthesis ◽  
Cuo Nps ◽  
Uv Visible ◽  
Justicia Adhatoda ◽  
Xrd Patterns

Aims: To determine the antibacterial activity of CuO nanoparticles (CuO NPs) synthesized by Justicia adhatoda leaf extract. Study Design:  Synthesis, characterization and antibacterial activity determination of CuO NPs. Place and Duration of Study: PG and Research Department of Chemistry, V.O.Chidambaram College, Tuticorin, Tamilnadu, India, between April 2019 and April 2020. Methodology: CuO NPs were synthesised using Justicia adhatoda leaf extract. UV-Visible spectroscopy was used to characterize CuO NPs. The role of biomolecules in plant extract in the formation of the CuO NPs was identified using Fourier transform infrared spectroscopy. The particle size and lattice properties of CuO NPs were determined using XRD. The surface morphology of CuO NPs was studied using SEM. The presence of Cu and O in CuO NPs was confirmed using EDAX analysis. Bacterial antimicrobial activity was investigated. Results: An absorbance band at 285 nm in the UV–visible spectrum clearly revealed the formation of CuO NPs. In the FTIR, CuO NPs had a distinct absorption peak at 608 cm-1, confirming metal–oxygen stretching in Cu-O nanostructures. The presence of crystalline CuO NPs was confirmed by XRD patterns, and they were found to be spherical in shape with a size range of 23.21–37.57 nm, as evidenced by FESEM. The biosynthesized CuO NPs exhibited a strong antibacterial activity against Staphylococcus epidermidis and Bacillus cereus bacteria. Conclusion: Justicia adhatoda leaf extract mediated CuO NPs have shown significant antibacterial activity and they are considered potent antibacterial agents.

Liquid-liquid extraction of succinate using a dicopper cryptate

2020 ◽  
Author(s):  
Riccardo Mobili ◽  
Sonia La Cognata ◽  
Francesca Merlo ◽  
Andrea Speltini ◽  
Massimo Boiocchi ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Visible Spectrum ◽  
Tca Cycle ◽  
Residual Concentration ◽  
Waste Products ◽  
Liquid Liquid Extraction ◽  
The Tca Cycle ◽  
Quantitative Extraction ◽  
Uv Visible

<div> <p>The extraction of the succinate dianion from a neutral aqueous solution into dichloromethane is obtained using a lipophilic cage-like dicopper(II) complex as the extractant. The quantitative extraction exploits the high affinity of the succinate anion for the cavity of the azacryptate. The anion is effectively transferred from the aqueous phase, buffered at pH 7 with HEPES, into dichloromethane. A 1:1 extractant:anion adduct is obtained. Extraction can be easily monitored by following changes in the UV-visible spectrum of the dicopper complex in dichloromethane, and by measuring the residual concentration of succinate in the aqueous phase by HPLC−UV. Considering i) the relevance of polycarboxylates in biochemistry, as e.g. normal intermediates of the TCA cycle, ii) the relevance of dicarboxylates in the environmental field, as e.g. waste products of industrial processes, and iii) the recently discovered role of succinate and other dicarboxylates in pathophysiological processes including cancer, our results open new perspectives for research in all contexts where selective recognition, trapping and extraction of polycarboxylates is required. </p> </div>

scholarly journals Effect of methyl substituent on the solubility of 1,4-benzoquinone derivatives in n-octanol/water system

2020 ◽  
Vol 23 (5) ◽  
pp. 142-146
Author(s):  
Siti Mariyah Ulfa ◽  
Fath Dwisari ◽  
Ade Cintyia Sally ◽  
Mohammad Farid Rahman
Keyword(s):  
Shake Flask ◽  
Water System ◽  
Insertion Reaction ◽  
Log P ◽  
Methyl Substituent ◽  
Promising Candidate ◽  
New Drug ◽  
Alkyl Bromides ◽  
Ft Ir ◽  
Uv Visible

The solubility of the compound is a crucial task for new drug design. Quinone is a promising candidate to develop as a new drug. In this research, the synthesis of 1,4-benzoquinone derivatives, that is, 2-(5-bromoamyl)-3,5-dimethyl-1,4-benzoquinone (2a) and 2-(5-bromoamyl)-5-methyl-1,4-benzoquinone (2b) were carried out by decarboxylation and insertion reaction of alkyl bromides. The product 2a and 2b are purified using SiO2 gel column chromatography and analyzed by UV-Visible, FT-IR, and NMR. The yield of 2a is 13.75%, and 2b is 4.04%. The solubility of 2a and 2b, expressed by log P, is measured in the n-octanol/water (3:7 (v/v)) system by the shake flask method. The log P of 2a and 2b are 2.99 and 1.36, respectively. It is showed that the log P of 2a is higher compared to 2b. The presence of two methyl substituents on the quinone ring of 2a supports the increase of hydrophobicity of the compound in the n-octanol/water system.

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