Using Atomic Layer Deposition (ALD) to Immobilize Molecular Catalysts on Solid Powder Supports

While homogeneous molecular catalysts are valued for their high reaction specificity, they are not as easily recoverable at industrial scales as heterogeneous catalyst powders that can be rapidly separated from the reaction solution. Here, we will discuss a new approach using atomic layer deposition (ALD) to immobilize molecular catalysts onto heterogeneous powder supports to achieve this combination of selectivity and recoverability. In this presentation, we demonstrate applicability using a non-noble metal (nickel) molecular catalyst to do Suzuki carbon-carbon cross-coupling reactions. Due to extremely short catalyst lifetimes caused by dimerization, this catalyst exhibits limited catalytic reactivity under homogeneous conditions. However, when heterogenized and immobilized, product yields of over 90% can be achieved in aqueous conditions, and the catalytic activity is preserved through over five hundred recovery and wash cycles. Following this work, we will also report on how modification of the ALD surface chemistry and number of ALD cycles affect catalytic performance.