APPLICATION OF PALLADIUM ON GRAPHENE/GRAPHENE OXIDE CATALYST SYSTEMS TO CROSS-COUPLING AND

1. APPLICATION OF PALLADIUM ON GRAPHENE/GRAPHENE OXIDE CATALYST SYSTEMS TO CROSS-COUPLING AND C-H ACTIVATION REACTIONS Christopher T. Williams USC Keith C. Ellis VCU B. Frank Gupton VCU M. Samy El-Shall VCU Center for Rational Catalyst Synthesis Planning Grant Workshop University of South Carolina, Columbia, SC June 16, 2014

2. Overview: Understanding the unique performance of heterogenous Pd on graphene/graphene oxide catalysts for cross-coupling and C-H activation reactions • Excellent activity – extremely high TOF (108,000 h-1) • Less than 200 ppb Pd in the reaction product. • Easily recovered and recycled under batch reaction conditions • ➔ How does this work? • ➔ Can we expand to other Pd- • catalyzed reactions?

3. Industrial Relevance • Pd-catalyzed cross-coupling reactions are widely used due to their high atom economy and synthetic versatility • Pharmaceutical drug discovery/development, fine chemicals • Pd-catalyzed C-H activation reactions are an emerging complimentary technology with the same advantages • Palladium-catalyzed reactions are typically run homogeneously: • Significant downsides and liabilities: • Use ligands to stabilize catalyst and broaden reactivity window. • Commercial viability is limited due to product contamination • Proposed Solution: Development of heterogeneous catalysts can provide greater performance, stability, and recyclability with less contamination!

4. Goals of the Proposal • Characteriztion of Cross-Coupling Catalysts: • Use in-situ and ex-situ analytical methods to determine the surface properties of novel Pd/graphene catalysts that impart the remarkable catalytic activities before, during, and after use in cross-coupling reactions. • Expand Scope to C-H Activation Chemistry • Explore the ability of Pd(II)/graphene oxide to catalyze each of six C–H activation reactions

5. Proposed Hypotheses • Increased activity and stability of Pd in this system is related to the unique surface properties of graphene, which if understood, can be further tailored and optimized • Pd electronic properties influenced by graphene • Water is key actor for high activity due to surface interactions • Analytical methods can be applied to graphene surfaces in situ to examine Pd-graphene and Pd-substrate interactions • ATR-IR, HRTEM, AFM, Resonance Raman spectroscopy and flow reactor kinetic measurements • Technique can be employed under reaction conditions • Pd(II)/graphene oxide will catalyze C-H activation reactions, which utilize a novel Pd(II)/Pd(IV) catalytic cycle • We expect this system will exhibit similar catalytic properties that will overcome the current limitations of homogeneous reactions

6. Research Methods/ Techniques • ATR-IR • HRTEM • AFM • Resonance Raman • kinetic measurements • Techniques can be employed under reaction conditions In-Situ ATR-IR of Thin Catalyst Films Optimize reaction parameters, including • Additives • Alternative Oxidants • Chemo-/Regioselectivity • Substrate Scope • Time • Temperature • Heating Method • Solvent Continuous Flow Reactor: Obtain kinetics and stability data under identical conditions to spectroscopic measurements

7. Outcomes/ Deliverables – Year 1 • Successful characterization of surface properties of Pd/graphene under cross-coupling reaction conditions and identification of the critical catalyst properties that drive catalytic activity • Quantify the surface interactions between the metal and graphene support • CO adsorption in EtOH, H2O, and EtOH/H2O mixtures on Pd/graphene • Identification of adsorbed species (coupling reactants/products) on graphene and Pd/graphene in various solvents at room temperature • Obtain detailed kinetics of heterogeneous cross-coupling reactions • Measurement of adsorption behavior (including competitive adsorption) at different concentrations and temperatures in order to develop mechanistic models for these processes • Real-time monitoring of surface during cross-coupling reaction under optimized condition • Successful demonstration that Pd(II)/graphene oxide catalyzes C-H activation reactions • Feasibility studies in each of the six transformations • Optimization of reaction parameters for two of the transformation • Begin to characterize the surface properties of the catalyst in the Pd(II)/Pd(IV) catalytic cycle

8. Impact • Optimization of heterogeneous Pd(0)/graphene catalyst synthesis based on increased mechanistic understanding • Enhanced reaction performance under continuous flow conditions • Broaden the scope of heterogeneous catalysis by Pd(II)/graphene oxide • Add six additional heteroatom functionalizations to the toolkit of available reactions Duration of Project and Proposed Budget • One Year • $60,000