Electrochemical and spectroscopic behavior of trifluoromethylacetophenone in aqueous and micellar medium

1995 ◽  
Vol 73 (9) ◽  
pp. 1488-1496 ◽  
Author(s):  
Elodie Liotier ◽  
Guy Mousset ◽  
Christine Mousty
Keyword(s):  
Electrochemical Behavior ◽  
Ph Dependence ◽  
Asymmetric Induction ◽  
Micellar Medium ◽  
Medium Ph ◽  
Ketone Reduction ◽  
Aromatic Ketones ◽  
Uv Visible ◽  
Chiral Surfactants ◽  
Spectroscopic Behavior

The electrochemical behavior of 4-trifluoromethylacetophenone (TFMA) has been studied in aqueous (2 ≤ pH ≤ 10), micellar, and ethanolic solutions using polarographic techniques. A slow hydration process of the carbonyl group has been observed by means of polarography and UV–visible spectrophotometry. Besides the well-known pH dependence of the electroreduction of aromatic ketones, C—F bond cleavages concomitant to the ketone reduction occur under electrolysis conditions in alkaline medium (pH = 10) at a very negative potential (−1.7 V), leading to the formation of 4-methylacetophenone, which is reduced at this potential with formation of the carbinol and of symmetrical and dissymmetrical pinacols. Finally, the reduction of TFMA has been performed in the presence of chiral surfactants in order to test their ability to induce an asymmetric induction. Keywords: 4-trifluoromethylacetophenone, 4-methylacetophenone, electroreduction, micellar medium, chiral surfactants, hydration, C—F bond fission.

Elektrochemisches Verhalten der Nitrophenole und ihrer Reduktionsprodukte an Graphitelektroden/ Electrochemical Behavior of the Nitrophenols and Their Reduction Products at Graphite Electrodes

1981 ◽  
Vol 36 (7) ◽  
pp. 840-845 ◽  
Author(s):  
Elli Theodoridou ◽  
Dimitrios Jannakoudakis
Keyword(s):  
Aqueous Solutions ◽  
Electrochemical Behavior ◽  
Ph Dependence ◽  
Chemical Oxidation ◽  
Potential Range ◽  
Cyclic Voltammograms ◽  
Hanging Mercury Drop Electrode ◽  
Oxidation Peak ◽  
Graphite Electrodes ◽  
Reduction Potentials

Abstract The electrochemical reduction of the isomeric nitrophenols at graphite electrodes is investigated in aqueous solutions with pH = 1-13 and is compared with the electro-chemical oxidation of their reduction products. o-Nitrophenol and p-nitrophenol are reduced to the corresponding amines, as the observed oxidation peaks in their cyclic voltammograms can be simulated by those of o-and p-aminophenol. m-Nitrophenol is reduced to m-hydroxylaminophenol, as its oxidation peak appears at much more negative » potential than that of m-aminophenol, within the potential range of the oxidation of phenylhydroxylamine. The pH-dependence of the reduction potentials of the nitrophenols at the graphite electrodes is discussed in comparison with that at a hanging mercury drop electrode.

Chiral α-hydroxy acid-coadsorbed TiO2 photocatalysts for asymmetric induction in hydrogenation of aromatic ketones

2018 ◽  
Vol 54 (89) ◽  
pp. 12610-12613 ◽  
Author(s):  
Shigeru Kohtani ◽  
Akira Kawashima ◽  
Fumie Masuda ◽  
Momono Sumi ◽  
Yuichi Kitagawa ◽  
...  
Keyword(s):  
Surface Structure ◽  
Crystalline Phase ◽  
Hydroxy Acid ◽  
Asymmetric Induction ◽  
Tio2 Photocatalysts ◽  
Aromatic Ketones ◽  
Structure And Morphology ◽  
Phase Surface

In enantioselective photohydrogenation of aromatic ketones on TiO2, the enantioselectivity is strongly affected by not only chiral reagents but also the crystalline phase, surface structure, and morphology of TiO2.

Determination of sparfloxacin and besifloxacin hydrochlorides using gold nanoparticles modified carbon paste electrode in micellar medium

RSC Advances ◽  
2016 ◽  
Vol 6 (46) ◽  
pp. 39605-39617 ◽  
Author(s):  
Ali K. Attia ◽  
Amr M. Badawy ◽  
Samr G. Abd-Elhamid
Keyword(s):  
Gold Nanoparticles ◽  
Carbon Paste Electrode ◽  
Electrochemical Behavior ◽  
Modified Carbon Paste Electrode ◽  
Micellar Medium ◽  
Carbon Paste ◽  
Paste Electrode

Determination of sparfloxacin and besifloxacin hydrochlorides using gold nanoparticles modified carbon paste electrode in micellar medium AuCPE was used to study the electrochemical behavior of SPAR and BESI using CV and DPV in presence of SDS.

Unique electrochemical behavior of tantalum(V) phthalocyanine

2006 ◽  
Vol 10 (02) ◽  
pp. 69-75 ◽  
Author(s):  
Prudence Tau ◽  
Tebello Nyokong
Keyword(s):  
Electrochemical Behavior ◽  
Nmr Spectra ◽  
Square Wave ◽  
Electron Reduction ◽  
Spectroscopic Behavior

The electrochemical and spectroscopic behavior of tantalum(V) phthalocyanine are presented. The NMR spectra is consistent with the lack of symmetry of the complex. Cyclic (CV) and square wave (SWV) voltammetries, and spectroelectrochemistry, were employed in the study of the complex. Two one-electron reductions and a simultaneous 4-electron reduction were observed. Reduction occurs first at the metal to form a Ta (IV) species, followed by ring based processes.

Tetra-2,3-pyrazinoporphyrazines with externally appended pyridine rings 14: UV-visible spectral and electrochemical behavior of homo/heterobinuclear neutral and hexacationic macrocycles

2013 ◽  
Vol 17 (08n09) ◽  
pp. 896-904 ◽  
Author(s):  
Maria Pia Donzello ◽  
Daniela Vittori ◽  
David Futur ◽  
Zhen Fu ◽  
Claudio Ercolani ◽  
...  
Keyword(s):  
Electrochemical Behavior ◽  
Bathochromic Shift ◽  
Electronic System ◽  
Spectral Changes ◽  
Electronic Distribution ◽  
Low Concentrations ◽  
Half Wave ◽  
Visible Spectra ◽  
Uv Visible

Detailed UV-visible, electrochemical and spectroelectrochemical studies were carried out in DMSO on two known series of homo/heterobimetallic pyrazinoporphyrazine compounds, i.e.[( M′Cl 2) LM ] and [( PtCl 2)( CH 3)6 LM ]( I )6, where L = tetrakis-2,3-[5,6-di(2-pyridyl)pyrazino]porphyrazinato anion, M = Zn II , Mg II ( H 2 O ) or Pd II and M′ = Pd II or Pt II . The [( M′Cl 2) LM ] compounds, as obtained from the mononuclear species [LM], undergo only subtle UV-visible spectral changes and exhibit practically unchanged half wave potentials for reduction; thus, peripheral coordination to the [LM] macrocycles of a single PdCl 2 or PtCl 2 unit at one of the external dipyridinopyrazine fragments only minimally disturbs the σ/π electronic distribution within the entire porphyrazine unit. In contrast, quaternization by CH 3 I of the six unligated pyridine N atoms of the species [( PtCl 2) LM ] leading to formation of the hexacations [( PtCl 2)( CH 3)6 LM ]6+ results in a significant bathochromic shift (5–15 nm) of the Q-band positions, thus suggesting an enhanced electron-withdrawing effect determined by an incremented displacement of the σ/π electronic system towards the periphery of the macrocycle. Accordingly, there is a facilitated thermodynamic uptake of electrons upon going from [( PtCl 2)( CH 3)6 LM ]6+ to [( PtCl 2)( CH 3)6 LM ] n (n = 5+ → 2+). Noteworthy, the UV-visible spectra of the salt-like species [( PtCl 2)( CH 3)6 LM ]( I )6 in water at c = 5 × 10-5 M ) indicate the presence of a monomer-dimer equilibrium, persistent even at very low concentrations (ca. 5 × 10-7 M).

Photochemical studies on acyclic alkyl aromatic ketones in the solid state: asymmetric induction and increased chemoselectivity

Tetrahedron ◽  
2012 ◽  
Vol 68 (43) ◽  
pp. 8875-8879 ◽  
Author(s):  
Manling Ma ◽  
Wei Feng ◽  
Fang Guo ◽  
Chao Yang ◽  
Wujiong Xia
Keyword(s):  
Solid State ◽  
Asymmetric Induction ◽  
Aromatic Ketones

scholarly journals Mn(III)acetate-Induced Electron Transfer in Pentaammine Cobalt(III)Complexes of α-Amino Acids in Micellar Medium

2012 ◽  
Vol 9 (2) ◽  
pp. 912-917
Author(s):  
S. Udhayavani ◽  
K. Subramani
Keyword(s):  
Amino Acids ◽  
Electron Transfer ◽  
Sulphuric Acid ◽  
Carbonyl Compound ◽  
Carbonyl Compounds ◽  
Acidic Medium ◽  
Micellar Medium ◽  
Uv Visible ◽  
Experimental Findings ◽  
Catalyzed Oxidation

A micellar catalyzed oxidation of pentaamminecobalt(III) complexes of α-amino acids by Mn(III)acetate in acidic medium yielding nearly 100% Co(II) and about 100% carbonyl compounds are ultimate products. The unbound amino acids yield about 100% of carbonyl compound in presence of micelles. The effect of variation of sulphuric acid has been carried. The decrease in UV-Visible absorbance at λ=502 nm for Co(III) complex corresponds to nearly 100% of the initial absorbance. In spite of the stoichiometry of Mn(III) to unbound ligand is 2:1, the ratio of Mn(III) to cobalt(III) complex is 1:1 accounting for about 100% reduction at the cobalt(III) centre. The kinetic and stoichiometric results have been accounted. A suitable mechanism consistent with the experimental findings has been proposed by involving a radical cation intermediate.

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