Electrochemical Investigation of N-(Arylthio)phthalimides and Arylmethylphthalimidosulfonium Hexachloroantimonate Salts
A series of N-(arylthio)phthalimides was synthesized. The electrochemical reduction of N-(arylthio)phthalimides follows a stepwise mechanism, generating a radical anion intermediate. Computational analysis suggests the nitro derivative follows a different radical anion dissociation mechanism, meaning the substituent effect should be opposite to that observed. Rigorous application of dissociative electron transfer theory and gas phase calculations allow the rationalization of this phenomena. The N-(arylthio)phthalimides were also investigated as precursors for self assembled monolayer formation (SAM) on Au, where the nitro derivative showed excellent activity as a precursor. A series of arylmethylphthalimidosulfonium hexachloroantimonate salts was synthesized. The electrochemical reduction of the series follows a concerted mechanism. The investigation revealed a change in regioselectivity as a function of the aromatic substituent. For all species except the nitro derivative the S+―N cleavage was observed. For the nitro derivative the S+―CH3 cleavage was observed. The regioselectivity was rationalized on the basis of the gas phase calculations.