Palladium ion-induced supramolecular gel formation of tris-urea molecules

Abstract

A multicomponent supramolecular gel constructed from the self-assembly of pyridyl-substituted tris-urea 1 and Pd(OAc) 2 is reported. A mixture of 1 and Pd(OAc) 2 in dimethyl sulfoxide provided a supramolecular gel after brief ultrasound irradiation. The supramolecular gel changed into a sol/solution upon addition of chelating agents such as diamines and bidentate phosphine ligands. Dissociation of the coordination bonds between 1 and the palladium ion via addition of a chelating agent caused the phase transition. The Wacker oxidation of styrene was performed in the supramolecular gel. The reaction in the gel phase required a longer induction period to produce acetophenone than did the reaction in the homogeneous solution.