DEVELOPING QUINOLINE PYRIDINE IMINE IRON COMPLEXES FOR UPGRADING FEEDSTOCK OLEFINS

Abstract

Petrochemical and biomass-derived hydrocarbons, specifically those of butadiene and linear -olefins, are abundant synthetic feedstocks for transformations yielding commercially valuable materials. Redox-active (PDI) iron complexes are widely used for catalyzing hydrovinylation and [2+2] cycloaddition reactions to achieve new hydrocarbon architectures. This work reports a new class of modulable, redox-active quinoline pyridine imine (QPI) ligands originally targeted to access diasteroselective [2+2] cycloaddition reactions. Preliminary studies of these complexes in the Chirik group show that despite the similar electronic and structural properties of (QPI) iron methyl and (PDI) iron methyl complexes, reactivity diverges when under catalytic conditions with butadiene and ethylene. Namely, (QPI) iron methyl complexes favor hydrovinylation products, while (PDI) favors [2+2] cycloaddition complexes. Stability and activity deactivation pathways were also encountered while attempting to access (QPI) iron(0) species, known precatalysts for [2+2] cycloaddition and hydrovinylation reactions. This project synthesizes a library of (QPI) ligands of varying substituents to prevent catalyst deactivation pathways and elucidate the interesting hydrovinylation reactivity observed with these complexes.