Cyclic Voltammetric Studies of Charge Transfer Reactions at Highly Boron-Doped Polycrystalline Diamond Thin-Film Electrodes

1995 ◽  
Vol 67 (17) ◽  
pp. 2812-2821 ◽  
Author(s):  
Shokoofeh. Alehashem ◽  
Fred. Chambers ◽  
Jerzy W. Strojek ◽  
Greg M. Swain ◽  
Rajeshuni. Ramesham
Keyword(s):  
Thin Film ◽  
Charge Transfer ◽  
Polycrystalline Diamond ◽  
Transfer Reactions ◽  
Cyclic Voltammetric ◽  
Diamond Thin Film ◽  
Boron Doped ◽  
Voltammetric Studies ◽  
Charge Transfer Reactions ◽  
Cyclic Voltammetric Studies

Electron transfer reactions. Reaction of nitrogen heterocycles with potassium

1990 ◽  
Vol 68 (6) ◽  
pp. 969-975 ◽  
Author(s):  
Mohammed Muneer ◽  
Prashant V. Kamat ◽  
Manapurathu V. George
Keyword(s):  
Benzoic Acid ◽  
Pulse Radiolysis ◽  
Nitrogen Heterocycles ◽  
Transfer Reactions ◽  
Radical Ions ◽  
Cyclic Voltammetric ◽  
Reduction Potentials ◽  
Potassium Superoxide ◽  
Voltammetric Studies ◽  
Cyclic Voltammetric Studies

The results of our studies on potassium-induced transformations of some selected nitrogen heterocycles are presented. The substrates under investigation include 2,3-diphenylindole (1a), 2,3-diphenyl-1-methylindole (1b), 1,2,3-triphenylindole (1c), 2,3,4,5-tetraphenylpyrrole (5a), 1,2,3,5-tetraphenylpyrrole (5b), 1-benzyl-2,3,5-triphenylpyrrole (5c), 2,4,5-triphenyloxazole (15a), 4,5-diphenyl-2-methyloxazole (15b), 2,4-diphenyl-5-methyloxazole (15c), and 2,4,5-triphenylimidazole (19). Treatment of 1a with potassium in THF gave 9H-dibenzo[a,c]carbazole (3a), whereas 1c gave a mixture of 9-phenyl-9H-dibenzo-[a,c]carbazole (3c) and 2,3-diphenylindole (1a). Under identical conditions, 1b gave only the cleavage product 1a. In contrast, when the reactions of 1a,c were carried out with potassium in THF saturated with oxygen, and with potassium superoxide in benzene containing 18-crown-6, a mixture of 2-benzamidobenzophenone (4a), the carbazoles 3a,c, and 1a was formed. Although no product was isolated on treatment of 5a with potassium in THF, the reaction of 5a with potassium in THF saturated with oxygen gave a mixture of tetraphenylpyrazine (7a), the benzoylaminostilbene 8a, the lactam 12a, benzamide (11a), and benzoic acid (14). Similar results were obtained in the reaction of 5a with potassium superoxide. The reaction of N-substituted pyrroles such as 5b,c with potassium gave the NH pyrrole 9b in each case, whereas the reaction of 5b,c with potassium in THF, saturated with oxygen, gave a mixture of 9b, the butanone 10b, the 1,4-dione 13b, the lactam 12b, the amides 11a–c, and benzoic acid (14). Attempted reactions of 5b,c with potassium superoxide did not give any isolable product; most of the starting material could be recovered unchanged in each case. A mixture of N-(1,2-diphenylethyl)benzamide (18a) and benzoic acid (14) was formed in the reaction of the oxazole 15a with potassium, whereas 15b,c, under analogous conditions, gave the N-vinylamides 17b,c and benzoic acid (14). In contrast, treatment of the imidazole 19 with potassium in THF did not give any product; however, when the reaction of 19 was carried out with potassium in THF saturated with oxygen, and with potassium superoxide, dibenzamide (21) was isolated, in each case.Radical ions have been invoked as intermediates in the transformation of the different substrates to the observed products. Cyclic voltammetric studies have been carried out to measure the reduction potentials of these radical anion intermediates. These radical anions have also been generated by pulse radiolysis in methanol, and their absorption spectra recorded. Keywords: nitrogen heterocycles, radical ions, potassium-induced transformations, pulse radiolysis, cyclic voltammetry.

Electron transfer reactions. Reaction of nitrones with potassium

1987 ◽  
Vol 65 (9) ◽  
pp. 2039-2049 ◽  
Author(s):  
Konda Ashok ◽  
Pallikkaparambil M. Scaria ◽  
Prashant V. Kamat ◽  
Manapurathu V. George
Keyword(s):  
Electron Transfer ◽  
Transfer Reactions ◽  
Radical Anions ◽  
Cyclic Voltammetric ◽  
Electron Transfer Reactions ◽  
Reduction Potentials ◽  
Dimeric Product ◽  
Voltammetric Studies ◽  
Electron Transfer Processes ◽  
Cyclic Voltammetric Studies

Treatment of nitrones (1a–d, 26a,b, 34, 49) with potassium in tetrahydrofuran (THF) gives rise to radical anion (2a–d, 27a,b, 35, 50) and dianion intermediates (3a–d, 28a,b, 36) through electron transfer reactions. These intermediates undergo further transformations to give a variety of products. Thus, the aldehydonitrones (1a–d) give the corresponding aldehydes (10a–c), carboxylic acids (25a–c), and azobenzenes (19a,d), whereas the ketonitrones (26a,b) give deoxygenation products (31a,b). The nitrone 34 gave a mixture of products consisting of benzoic acid (25a), dibenzyl (48), the dimeric product 38, and tetraphenylpyrazine (46), whereas 49 did not give any isolable product. Cyclic voltammetric studies have been employed to measure the reduction potentials for both one-electron and two-electron transfer processes, leading to the radical anions and dianions respectively. These intermediates have been characterized through their electronic spectra and they were quenched by oxygen. Pulse radiolysis of the nitrones 1a–d, 26a,b, 34, and 49 also gave the corresponding radical anions 2a–d, 27a,b, 35, and 50, characterized by their spectra.

Voltammetric and amperometric study of electrochemical activity of boron-doped polycrystalline diamond thin film electrodes

1996 ◽  
Vol 333 (1-2) ◽  
pp. 125-130 ◽  
Author(s):  
Jiali Wu ◽  
Jianzhong Zhu ◽  
Lei Shan ◽  
Nianyi Cheng
Keyword(s):  
Thin Film ◽  
Polycrystalline Diamond ◽  
Electrochemical Activity ◽  
Diamond Thin Film ◽  
Boron Doped ◽  
Thin Film Electrodes

Cyclic voltammetric studies. II. Substituted anilines in acetonitrile

1974 ◽  
Vol 27 (11) ◽  
pp. 2495 ◽  
Author(s):  
M Mohammad ◽  
AY Khan ◽  
M Afzal ◽  
A Nisa ◽  
R Ahmed
Keyword(s):  
Charge Transfer ◽  
Chemical Reaction ◽  
Substituted Anilines ◽  
Cyclic Voltammetric ◽  
Triangular Wave ◽  
Irreversible Chemical Reaction ◽  
Multistep Process ◽  
Voltammetric Studies ◽  
Cyclic Voltammetric Studies

Results of single sweep triangular wave cyclic voltammetric studies on some substituted anilines in acetonitrile are reported. It has been found that, while the first reduction steps of nitroanilines are reversible that of chloroaniline is irreversible. The second reduction steps were found to be irreversible and the overall picture emerged of a multistep process involving reversible charge-transfer steps followed by an irreversible chemical reaction.

Electrochemical characterization of boron-doped polycrystalline diamond thin-film electrodes

1995 ◽  
Vol 353 (2) ◽  
pp. 171-173 ◽  
Author(s):  
Peilin Zhu ◽  
Jianzhong Zhu ◽  
Shenzhong Yang ◽  
Xikang Zhang ◽  
Guoxiong Zhang
Keyword(s):  
Thin Film ◽  
Polycrystalline Diamond ◽  
Electrochemical Characterization ◽  
Diamond Thin Film ◽  
Boron Doped ◽  
Thin Film Electrodes

Effect of sp[sup 2]-Bonded Nondiamond Carbon Impurity on the Response of Boron-Doped Polycrystalline Diamond Thin-Film Electrodes

2004 ◽  
Vol 151 (9) ◽  
pp. E306 ◽  
Author(s):  
Jason A. Bennett ◽  
Jian Wang ◽  
Yoshiyuki Show ◽  
Greg M. Swain
Keyword(s):  
Thin Film ◽  
Polycrystalline Diamond ◽  
Carbon Impurity ◽  
Diamond Thin Film ◽  
Boron Doped ◽  
Nondiamond Carbon ◽  
Thin Film Electrodes

Standard Electrochemical Behavior of High-Quality, Boron-Doped Polycrystalline Diamond Thin-Film Electrodes

2000 ◽  
Vol 72 (16) ◽  
pp. 3793-3804 ◽  
Author(s):  
Michael C. Granger ◽  
Malgorzata Witek ◽  
Jishou Xu ◽  
Jian Wang ◽  
Mateusz Hupert ◽  
...  
Keyword(s):  
Thin Film ◽  
Electrochemical Behavior ◽  
Polycrystalline Diamond ◽  
High Quality ◽  
Diamond Thin Film ◽  
Boron Doped ◽  
Thin Film Electrodes

The electrochemical activity of boron-doped polycrystalline diamond thin film electrodes

1993 ◽  
Vol 65 (4) ◽  
pp. 345-351 ◽  
Author(s):  
Greg M. Swain ◽  
Rajeshuni. Ramesham
Keyword(s):  
Thin Film ◽  
Polycrystalline Diamond ◽  
Electrochemical Activity ◽  
Diamond Thin Film ◽  
Boron Doped ◽  
Thin Film Electrodes
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