Electrochemical crystallization of tetraphenylphosphonium and tetraphenylarsonium fullerides

Abstract

The electrocrystallization of tetraphenylphosphonium and tetraphenylarsonium halide double salts of the C^– ₆₀ and C^– ₇₀ fulleride anions has been investigated. The mechanism of precipitation, growth of single crystals and application to separation and generation of various reduced states of the fullerenes are discussed. Electrochemical methods have demonstrated an initial dissolution–precipitation mechanism exhibiting a high level of supersaturation, followed by growth of a solid phase of low solubility in 1,2-dichlorobenzene. Single crystals with at least 400 µm face dimensions have been grown. Methods for generation of fluxes of either the doubly charged anions or of the fullerene precursors from the salts are described.