Synthesis and Catalytic Activity of PolyHIPE-Supported NHC-Bearing Ruthenium Initiator for ROMP

Abstract

Although generally the ruthenium based homogeneous catalysts are used to initiate metathesis reactions, immobilization of homogeneous ruthenium metathesis catalysts on various solid supports has attracted a lot of interest from the scientific community in recent years. In this article, the synthesis and applications of highly active polyHIPE-supported N-heterocyclic carbene ligand (NHC)-bearing ruthenium alkylidene metathesis catalysts were described. Open-celled porous polyHIPE foams having surface area of 575 m2/g were synthesized by polymerization of the continuous phase of w/o high internal phase emulsions. Then RuCl2(PCy3)(H2IMes)(=CHPh) complex was attached to porous polyHIPE solid supports via alkylidene exchange reactions to obtain new olefin metathesis catalysts. The amount of initiator loadings was determined by ruthenium analysis via ICP-OES and found to be 0.0336–0.0514 mmol/g. Subsequently, the activity of new catalysts was tested in ring opening metathesis polymerization of norbornene and a series of its derivatives.