Rational Design of Double Tethered Metallacyclobutane Complexes

Courtney Sever, Parker Boeck, Ushnish Mandal, Adam Veige

University of Florida

Double tethered metallacyclobutane catalysts are a new and promising class of catalysts. Two tethering ligands attached to a metallacyclobutane core allows for greater control over the stereoselectivity and activity in polymerizations of both alkene and alkyne substrates.  With rational design choices, significant progress has been made in improving the performance of these catalysts.  Changing the imido ligand from an aromatic group to more of a three-dimensional adamantyl group, cis selectivity in polynorbornene improved by 10%. Redesigning the tethering ligand to have chirality, the activity of the resulting catalyst is unmatched when compared to other double tethered metallacyclobutane complexes.