Tetraalkylammonium superoxide

Tetraalkylammonium superoxide, 736 1,1,2,2-Tetraarylcyclopropanes, photooxygenation, 205-6 Tetrachloroethene, jr-complex with ozone, 731-2... 

Oxygen is reduced at the mercury cathode in a dipolar aprotic solvent containing a quaternary ammonium salt to form the superoxide ion, 02 , in a reversible one-electron transfer process 165 166 The reduction takes place at -0.8 V (SCE) and concentrations of tetraalkylammonium superoxide of at least 0.1 M can be obtained (the half life of the superoxide ion in dimethylformamide is about 40 min at room temperature). 

Chemical studies have employed either electrogenerated 02 or solutions or suspensions of K02 Dipolar aprotic solvents are usually used in either case as 62 is quite sensitive to proton sources. The electrogenerated tetraalkylammonium superoxides are both soluble and stable in a variety of dipolar aprotic solvents (DMSO, DMF, CH CN, pyridine, acetone) ( 2). The... 

If a tetraalkylammonium salt is used as supporting electrolyte, this process is either reversible or quasi-reversible and occurs at around -0.8 V vs aqueous SCE in various aprotic solvents and with various electrode materials (Hg, Pt, GC). If a Bmisted acid is added to the solution, the first step is converted to a two-electron process 0 produced in the first step is protonated to form 02H, which is more reducible than 02. Thus, 02H is further reduced to 02H at the potential of the first step. According to detailed polarographic studies in H20-DMS0 mixtures, about 30% v/v water is needed to convert the one-electron process to the two-electron process [41]. A metal ion, M+, interacts with 02 to fonn an ion-pair M+-02 (often insoluble) and shifts the half-wave potential of the first wave in a positive direction [42]. Electrogenerated superoxide 02 can act either as a nucleophile or as an electron donor and has been used in organic syntheses [43],... 

---