Immobilizedcatalysts are most often bound to oxide surfaces by bifunctional phosphinelinkers. Their success is always crucially dependent on the nature of thephosphine linkers. Flexible linkers, such as Ph2P(CH2)3Si(OEt)3,however, can lead to catalyst deactivation by dimerization and by contact ofthe metal center with the reactive oxide surface. Here we demonstrate thattetraphosphine linkers with a rigid tetraphenylelement (E = C, Si, Sn) backbonecan easily be synthesized and immobilized on oxide supports via phosphoniumgroups, leading to catalysts with prolonged lifetimes. Multinuclear solid-stateNMR shows that catalyst dimerization and metal/surface contacts are preventedmechanically, and immobilized Rh hydrogenation complexes, for example, can berecycled in a batchwise manner more than 30 times.

Rigid tetraphenylelement linker scaffolds that
prevent interactions of catalysts with oxide supports

241st National Meeting (2011)

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Rigid tetraphenylelement linker scaffolds that prevent interactions of catalysts with oxide supports