UCLA

Multi-step processes, such as catalytic cycles, proceed through one or more intermediates that may participate in unwanted side reactions, leading to inefficiency and waste. Further, these intermediates may have a short shelf life and/or pose a safety concern. Thus, the development of methods to carry out multi-step processes to generate and utilize intermediates in one pass is of great desire. Biology manages its complex reaction network of multi-step, multi-enzyme processes by numerous means, namely spatial control via compartmentalization. By controlling where certain processes occur and the diffusion of key intermediates between reaction sites, biology efficiently carries out multiple concurrent reaction sequences efficiently with minimal competing pathways. For example, carboxysomes enhance the rate of CO2 fixation by co-encapsulating carbonic anhydrase and ribose 1,5-bisphosphate carboxylase-oxygenase while excluding deactivating oxygen (O2). Inspired by spatial control in biology, my research seeks to adapt such methods of spatial control to construct efficient multi-step, multi-catalyst organometallic and electrochemical processes. In this manner, commodity chemicals can be produced from abundant feedstocks while obviating intermediate isolation and work up. Electrochemistry has emerged within the last few decades at the forefront of small molecule activation, particularly of environmental pollutants such as CO2, and organometallic chemistry is apt to further utilize products of electrochemical small molecule activation owing to decades of rich literature in homogeneous catalyst development. However, it is highly likely that catalyst - catalyst, catalyst - substrate, or substrate - substrate interference may impede the integration of multiple processes. Potential undesired interference may be circumvented by spatially separating while co-localizing the electro- and organometallic (or any type) catalysts in one reactor system allowing the transport of intermediates between them. The projects outlined below demonstrate the critical role spatial control and mass transport have in constructing efficient multi-step, multi-catalyst electro- and/or organometallic processes.