One of the main challenges facing quantum information science (QIS) is the development of robust qubits that can be operated under ambient conditions. Current state-of-the-art anionic nitrogen-vacancy...

Redox mediators continue to emerge as powerful tools for driving electrochemical reactions, preventing electrode surface fouling and/or facilitating redox processes at milder operating potentials than direct electrolysis requires. In this study, we demonstrate a tandem electrocatalytic approach using a Cp2Co redox mediator and (dppe)CoCl2 precatalyst to selectively hydrogenate a variety of alkynes to cis-alkenes. Controlled potential electrolysis (CPE) at the potential of the mediator (Eapp = −1.45 V vs Fc+/0) successfully generates a variety of terminal and internal alkenes in moderate to good yields. Notably, substrates with tethered Lewis bases further drive selectivity almost exclusively for the Z isomer. Mechanistic investigation of the tandem catalytic reaction via CV and DFT point toward a multisite proton-coupled electron transfer (MS-PCET) step involving a hydride-free pathway where Cp2Co facilitates the reduction of alkyne- and acid-bound (dppe)Co(I)/(0). This developed methodology can be applied toward the synthesis of cis-stilbenoid natural products, as demonstrated with combretastatin A-4. It is also amenable to more practical gram-scale setup and proceeds with up to 99% Faradaic efficiency.

Anodic oxidation unlocks C─N bond formation in electron-rich fluoroarenes. Spatial separation of redox events extends the lifetime of active intermediates, expands the scope of nucleophilic aromatic ...

The development of electroreductive Fe-catalyzed processes for organic synthesis has remained scarce compared to other earth-abundant metals despite inherent advantages such as cost, low-toxicity, and accessible redox. Through stability of the Fe center using polydentate and/or redox-active ligand frameworks, pioneering work in reductive chemical catalysis for C–C π-bond hydrogenation and electrocatalytic CO2 reduction sheds light on strategies to harness reduced Fe species electrochemically for organic transformations. Using a tetraphos ligand (P3P), we demonstrate that electroreductive Fe catalysis can be achieved using cobaltocene (Cp2Co) as a redox mediator with alkyne semi-hydrogenation as a model system; the hydrogen evolution reaction (HER) is mitigated by operating at the potential of the redox mediator (Eapp = −1.45 V vs Fc+/0) to access Fe(II/I) reduction as opposed to Fe(II/0) over-reduction. A combination of cyclic voltammetry and controlled potential electrolysis (CPE) studies support a rate-limiting electron transfer step to generate a crystallographically characterized (P3P)Fe(I) which can engage in a nonstereoselective reductive protonation step with internal aryl alkynes and acid. Stoichiometric studies involving a related (P3P)Fe(II)-H ligand suggest that this tandem electrocatalytic system does not operate through a canonical Fe–H mechanism. Lastly, a small survey of diaryl alkynes with unique functional group tolerance is conducted, giving stilbene products with up to 8 turnovers per Fe.

Selective semi-hydrogenation to generate alkenes from alkynes is an invaluable method to access olefins for materials, pharmaceuticals, and nat-ural products. Electrochemical transition-metal-catalyze...

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Electrochemical systems with increasing complexity are gaining importance in catalytic energy conversion applications. Due to the interplay between transport phenomena and chemical kinetics, predicting optimization is a challenge, with numerous parameters controlling the overall performance. Zone diagrams provide a way to identify specific kinetic regimes and track how variations in the governing parameters translate the system between either adverse or optimal kinetic states. However, the current procedures for constructing zone diagrams are restricted to simplified systems with a minimal number of governing parameters. We present a computationally based method that maps the entire parameter space of multidimensional electrochemical systems and automatically identifies kinetic regimes. Once the current output over a discrete set of parameters is interpreted as a geometric surface, its geometry encodes all of the information needed to construct a zone diagram. Zone boundaries and limiting zones are defined by curved and flat regions, respectively. This geometric framework enables a systematic exploration of the parameter space, which is not readily accessible by analytical or direct numerical methods. This will become increasingly valuable for the rational design of electrochemical systems with intrinsically high complexity.

ConspectusFuel-forming reactions such as the hydrogen evolution reaction (HER) and CO2 reduction (CO2R) are vital to transitioning to a carbon-neutral economy. The equivalent oxidation reactions are a...

Shono-type oxidation to generate functionalized heterocycles is a powerful method for late-stage diversification of relevant pharmacophores; however, development beyond oxygen-based nucleophiles remai...