Designing, Probing and Utilizing Weak Attractive Ligand–Polymer Interactions in Catalysis

We have developed fluorinated chelating σ-aryl Group 4 precatalysts that display spectroscopically (NMR) and structurally (including neutron diffraction) discernible intramolecular C–H···F–C interactions. Advanced multinuclear NMR experiments have revealed a substantial scalar component for the observed ¹H-¹⁹F coupling, thus confirming that these C−H···F−C interactions occur with chemical connectivity and are genuine. These complexes can be considered as synthetic models of ‘weak attractive ligand–polymer interactions’ (WALPI), a new strategy in olefin polymerization that offers the capability to control and manipulate the reactivity of the polymer chain during catalysis. For example, these interactions may be harnessed to stabilize hitherto unstable intermediates as well as impede undesirable processes, and can pave the way towards new polymerization reactions. In this context, reports have appeared that point to the applicability and generality of the WALPI concept for modulating polymerization processes. A shape-persistent bimetallic design approach for the catalytic production of valuable feedstock (from sustainable resources) and polymers will be presented.