Functionalised microgels: novel stabilisers for catalytically active metal colloids

Microgel stabilised palladium colloids have been prepared by a novel strategy based on the synthesis of microgels upon radical solution copolymerisation of suitable functional monomers containing sulfonic acid groups. These microgels can be conveniently loaded with Pd2+ ions which are subsequently reduced. The resulting metal colloids (10-20 nm diameter) can be precipitated from the reaction mixture and redispersed in suitable solvents. Preliminary tests indicate that microgel stabilised palladium colloids are active catalysts for the vinylation of aryl iodides and bromides (Heck reaction).