Reactions of cation radicals of EE systems. 10. The influence of ion association on cation radical disproportionation

Abstract

Disproportionation equilibria of the cation radicals of 10-phenylphenothiazine, thianthrene, and 9,10-diphenylanthracene have been voltammetrically characterized in acetonitrile, butyronitrile, nitrobenzene, and methylene chloride containing hexafluorophosphate, tetrafluoroborate, and perchlorate supporting electrolytes. Disproportionation was observed to be significantly influenced by associative interactions between the oxidized forms of the substrates and the anions of the supporting electrolytes. Disproportionation was found to be favored by anions of greater ionic potential. This anion effect in associated systems was observed to be "leveled" by solvents of increased polarity. In the absence of ion association, disproportionation was found to be favored by more polar solvents.

Assembly and Stepwise Oxidation of Interpenetrated Coordination Cages Based on Phenothiazine

“…As shown in Figure 5, [6] 8 C + hydrolyses much faster than [3]C + , a fact that we assign to the possibility of an intramolecular, hence faster, disproportionation pathway to give phenothiazine dications, which are known intermediates in the reaction with water to give phenothiazine-5-oxide. [15] Furthermore, ESI mass spectrometric examination of the hydrolysis products [Pd 4 (3) 8Àn (4) n ] (0 n 8) showed a deviation of the signal pattern from the statistical expectation, which further supports the prevalence of an intramolecular disproportionation pathway. The use of H 2 18 O confirmed water as the oxygen source (see the Supporting Information).…”

“…[12] The pharmaceutically important heterocycle phenothiazine (1) [13] serves as a promising candidate for the preparation of such materials because of its beneficial redox behavior of readily undergoing a reversible one-electron oxidation to its radical cation (E 0 =+ 0.73 V in acetonitrile versus SCE) [14] with the possibility of further oxidation or disproportionation processes. [15] Consequently, monomeric phenothiazine species have been widely used as electron-donor components in systems capable of photoinduced charge separation, [16] as charge carriers in light-powered molecular machines, [17] and as redox shuttles in lithium-ion batteries. [18] To enhance the electro-and photochemical properties and to be able to study cooperative phenomena, Müller and co-workers have prepared phenothiazine-based conjugated oligomers [19] and rings [20] by using a covalent approach based on CÀC crosscoupling reactions.…”

Spectrophotometric Kinetic and Mechanistic Investigation of Chlorpromazine Radical Cation with Hexachloroiridate (IV) in Catalyzed Aqueous Acid Medium

“…In late years, there has been significant interest in these drugs due to the reactivity of phenothiazine as neutral as well as radical cationic [4][5][6] form, and some interesting mechanistic approaches of these radical with nucleophiles have been investigated. [7][8][9][10][11][12] The mainly used Phenothiazine based drugs are substituted at the position 2 and 10, [13] and the types of substituent have chemical and reactivity properties of these compounds governing their uses.…”

Promazine π-mers formation at a 1,2-dichloroethane/water interface

“…They are easily oxidized photochemically [29][30][31][32][33] or electrochemically [34], resulting in the formation of a stable cation radical as an intermediary of the final product, the corresponding sulfone.…”