Homogeneous palladium catalysts are used extensively in organic synthesis, particularly in carbon-carbon coupling reactions, but have substantial drawbacks including difficulty removing the catalyst from reaction products and the lack of catalyst recyclability. Many of the issues with homogeneous cross-coupling catalysts can be addressed by attaching the catalyst to a solid support. However, many of these materials are composed of a mixture of surface species that are difficult to characterize, and the structure of their active sites is not well-understood. Because of this, synthesizing well-defined surface-supported palladium catalysts and developing robust surface-attachment chemistries is important.<br/>            A series of novel immobilization strategies will be used to support N-heterocyclic carbene (NHC)-functionalized molecular palladium complexes on both polymer and metal oxide supports, and their reactivity in cross-coupling reactions will be discussed. Attachment chemistries investigated include tetrazine-norbornene cycloaddition click chemistry, incorporation via ring-opening metathesis polymerization (ROMP) into a poly(norbornene) polymer, and immobilization onto metal oxide surfaces via both silyl ether and phosphonate linkages. The interplay between catalyst stability and recyclability will be addressed to highlight the importance of robust immobilization strategies in the preparation of functional and truly surface-supported molecular catalysts.<br/><br/>

Immobilization strategies for surface-supported molecular palladium cross-coupling catalysts

253rd National Meeting (2017)

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