Electron transport via metalloporphyrins

1978 ◽  
Vol 56 (10) ◽  
pp. 1381-1388 ◽  
Author(s):  
Eugene C. Johnson ◽  
Tony Niem ◽  
David Doolphin
Keyword(s):  
Electron Transfer ◽  
Electron Transport ◽  
Heme Proteins ◽  
Room Temperature ◽  
Cation Radical ◽  
Cation Radicals ◽  
Controlled Potential Electrolysis ◽  
Controlled Potential ◽  
Internal Electron

The controlled potential electrolysis of Ni(II) meso-tetraphenylporphyrin (Ni(II)TPP) gives at room temperature the corresponding metalloporphyrin π-cation radical [Ni(II)TPP]+ •. Upon freezing a solution of the π-cation radical to 77 K an internal electron transfer occurs to give [Ni(III)TPP]+. A discussion of the routes of electron transport in heme proteins is given, and the roles of metalloporphyrin π-cation radicals in electron transport is evaluated.

Study of the Influence of Water on Oxidative Properties of Fe3+ in ZSM-5 Zeolite Channels

2002 ◽  
Vol 67 (12) ◽  
pp. 1743-1759 ◽  
Author(s):  
Gabriel Čík ◽  
Milada Hubinová ◽  
František Šeršeň ◽  
Vlasta Brezová
Keyword(s):  
Ion Exchange ◽  
Room Temperature ◽  
Cation Radical ◽  
Organic Substrates ◽  
Cation Radicals ◽  
Influence Of Water

The interactions of phenol and thiophene with Fe3+ ions have been studied in ZSM-5 zeolite channels in the presence of water. The Fe-ZSM-5 was prepared by the ion exchange of Fe3+ for Na+. The Fe3+ ions in zeolite channels have unsaturated co-ordination spheres and oxidize organic substrates (phenol, thiophene) at room temperature. The interaction of Fe3+ with phenol gives rise to the stabilized cation-radical PhOH•+ and thiophene forms low oligomers (2-6 monomeric units). The oligomers are present in the neutral as well as oxidized form as cation-radicals (polarons). The formation of dications (bipolarons) has not been observed.

scholarly journals Studies of Biologically Active Heterocycles: Synthesis, Characterization and Antimicrobial Activity of Some 5-Substitutd-2-Amino-1,3,4-Oxadiazoles

1970 ◽  
Vol 9 (1) ◽  
pp. 53-59
Author(s):  
Sanjeev Kumar
Keyword(s):  
Antifungal Activity ◽  
Electrochemical Oxidation ◽  
Room Temperature ◽  
Antibacterial Agents ◽  
Antimicrobial Agents ◽  
Biologically Active ◽  
Structural Assignment ◽  
Platinum Anode ◽  
Controlled Potential Electrolysis ◽  
Controlled Potential

In the present study, 5-substituted-2-amino-1,3,4-oxadiazoles (4a-k) have been synthesized by the electrochemical oxidation of semicarbazones (3a-k) using platinum anode at room temperature under controlled potential electrolysis in an undivided cell assembly. The structural assignment of these compounds (4a-k) has been made on the basis of elemental analysis, IR, 1H NMR and 13C NMR. The synthesized compounds were screened for their inhibiting activity against Klebsilla penumoniae, Escherichia coli, Bassilus subtilis and Streptococcus aureus and antifungal activity against Aspergillus niger and Crysosporium pannical and results have been compared with the standard antibacterial agents, Streptomycin and antifungal drug, Griseofulvin. The Compounds exhibited significant antibacterial activity and antifungal activity. Key words: Electrochemical oxidation; controlled potential; 5-substituted-2-amino-1,3,4-oxadiazole; semicarbazone; antimicrobial agents DOI: 10.3329/dujps.v9i1.7434 Dhaka Univ. J. Pharm. Sci. 9(1): 53-59 2010 (June)

Regioselective S—O vs. C—O bond cleavage in sulfenate ester radical anions

2005 ◽  
Vol 83 (9) ◽  
pp. 1473-1482 ◽  
Author(s):  
Donald LB Stringle ◽  
Mark S Workentin
Keyword(s):  
Electron Transfer ◽  
Bond Cleavage ◽  
Electrochemical Techniques ◽  
Radical Anions ◽  
Peak Potential ◽  
Dissociative Mechanism ◽  
Dissociative Electron Transfer ◽  
Controlled Potential Electrolysis ◽  
Controlled Potential ◽  
Singly Occupied Molecular Orbitals

The electron transfer (ET) reduction of benzyl benzenesulfenate ester (1) and tert-butyl benzenesulfenate ester (2) was investigated using electrochemical techniques. Analysis of the cyclic voltammetry of each compound suggests that the ET reduction proceeds via a stepwise dissociative mechanism. The voltammograms of 1 are similar to those of diaryl disulfides and it was found through controlled potential electrolysis (CPE) product studies that ET reduction leads to S—O bond cleavage. The voltammograms of 2 are dramatically different with a sharper dissociative wave occurring at a more negative peak potential. CPE experiments indicate products that result from ET leading to C—O bond cleavage in this case. DFT calculations of the singly occupied molecular orbitals (SOMOs) of 1 and 2 were performed and offer a rationale for the different reactivity of the two radical anions.Key words: sulfenate esters, dissociative electron transfer, electrochemistry, radical anions.

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