Polarographic reduction of 1-(p-substituted benzyl)-3-cyanopyridinium chlorides

1983 ◽  
Vol 48 (8) ◽  
pp. 2273-2283
Author(s):  
Františka Pavlíková-Raclová ◽  
Josef Kuthan
Keyword(s):  
Substituent Effects ◽  
Polarographic Reduction

Reduction of 3-cyanopyridinium salts has been studied on the mercury dropping electrode. Solvent and substituent effects and pH of the medium have been shown to modify in a certain extent differently the polarographic characteristics as compared with analogous 3-carbamoyl derivatives, which is due to higher electronegativity of the studied cations.

Substituent effects on polarographic reduction of some photographic color intermediates

1976 ◽  
Vol 54 (8) ◽  
pp. 1205-1210 ◽  
Author(s):  
Ahmad S. Shawali ◽  
Bahgat E. El-Anadouli
Keyword(s):  
Dissociation Constants ◽  
Substituent Effects ◽  
Protonated Form ◽  
Acid Dissociation ◽  
Polarographic Reduction ◽  
Substituent Constant ◽  
Acid Dissociation Constants ◽  
Controlled Potential Electrolysis ◽  
Half Wave ◽  
Controlled Potential

Polarographic reduction of two series of benzoylacetanilides has been investigated in 40% (by volume) ethanolic Britton–Robinson buffers. One series (A) contains substituents on the anilide moiety, and the second (B) has substituents on both the anilide and benzoyl moieties. Polarographic controlled-potential electrolysis data indicate that the electroactive species in both series is the protonated form (ArCOCH2CONHAr′)H+. The reduction half-wave potentials of anilides of series A were found to be independent of the nature of the substituent, whereas those of series B show a good linear relationship when plotted vs. the σ substituent constant of the substituent on the benzoyl moiety (ρ = 0.284, r = 0.995). Values of the acid dissociation constants of the keto (K1) and enol (K2) tautomers of the anilides of series A were calculated; unlike their E1/2 values, the pK1 data show a linear correlation with the Hammett substituent constant, σ. The pK2 values show, however, little variation with σ.

Substituent effects on electroreduction of the carbon-halogen bond

1981 ◽  
Vol 34 (11) ◽  
pp. 2331 ◽  
Author(s):  
RS Abeywickrema ◽  
EW Della
Keyword(s):  
Reduction Potential ◽  
Halogen Bond ◽  
Substituent Effects ◽  
High Yield ◽  
Polarographic Reduction ◽  
Electric Field Effects ◽  
Controlled Potential Electrolysis ◽  
Half Wave ◽  
Controlled Potential ◽  
Substituted 1

Polarographic reduction of a series of 4-substituted 1-iodobicyclo[2,2,2]octanes has been examined in an attempt to assess the effect of substituents on the half-wave reduction potential. It is found that the values of E� do not show a linear correlation with the relevant σ1 constants; the deviations are discussed in terms of the relative importance of the steric and electric field effects of the substituent. Controlled-potential electrolysis of a number of the substrates reveals that the hydrocarbon corresponding to fission of the carbon-iodine bond is formed in high yield.

scholarly journals Substituent Effects of Sulfur Groups. II. The Polarographic Reduction of the -S-O- Linkage, with Special Reference to Methyl Benzenesulfenate.

1970 ◽  
Vol 24 ◽  
pp. 1110-1112 ◽  
Author(s):  
Bernt J. Lindberg ◽  
Gunnar Samuelsson ◽  
Kauko K. Mäkinen ◽  
L. Kääriäinen ◽  
S. E. Rasmussen ◽  
...  
Keyword(s):  
Special Reference ◽  
Substituent Effects ◽  
Polarographic Reduction

Spectroscopic and electrochemical properties of intramolecularly hydrogen-bonded compounds. Ortho-hydroxyazobenzenes

1981 ◽  
Vol 59 (5) ◽  
pp. 821-827 ◽  
Author(s):  
Salvatore Millefiori ◽  
Arcangelo Millefiori
Keyword(s):  
Bond Formation ◽  
Substituent Effects ◽  
Lone Pair ◽  
Intramolecular Hydrogen Bonding ◽  
Photoelectron Spectra ◽  
Polarographic Reduction ◽  
Reduction Potentials ◽  
Half Wave ◽  
Experimental Findings ◽  
Intramolecular Hydrogen

The gas-phase uv photoelectron spectra and the half-wave polarographic reduction potentials in acetonitrile solutions of a series of 2-hydroxy-5-methylazobenzene have been determined. The first three IP's and the E1/2 values were linearly correlated with σ+ and σ constants, respectively. E1/2 can also be linearly related to the energy of the lowest unoccupied molecular orbital. Effects of the intramolecular hydrogen bonding on the pe spectra and on the polarographic reduction of the title compounds were evaluated by comparing the experimental findings in 2-hydroxy-5-methylazobenzene, 2-methoxy-5-methylazobenzene, and p-hydroxyazobenzene. On H-bond formation, the antibonding combination of the two nitrogen lone-pairs, n−, and the oxygen lone-pair is ionized at a slightly higher energy and at a lower energy, respectively, than in the non H-bonded compound. The first π-ionization band is slightly lowered in energy in the non H-bonded structure, probably owing to a normal substituent effect. These features are not maintained in the 4'-nitro derivative, where the band encompassing the n− ionization remains at the same potential in both structures, while the first π band in the non H-bonded compound moves toward higher IP. Spectral differences between the bonded and nonbonded structures are the result of a balance of substituent effects, and of both hydrogen bond and orbital interactions. The solution electron affinity of the studied compounds increases on H-bond formation by an amount comparable with the experimental strength of the H-bonding. INDO/S-CI calculations are in qualitative agreement with the experimental results.

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