Reductive electrosynthesis has faced long-standing challenges in applications to complex organic substrates at scale. Here, we show how decades of research in lithium-ion battery materials, electrolytes, and additives can serve as an inspiration for achieving practically scalable reductive electrosynthetic conditions for the Birch reduction. Specifically, we demonstrate that using a sacrificial anode material (magnesium or aluminum), combined with a cheap, nontoxic, and water-soluble proton source (dimethylurea), and an overcharge protectant inspired by battery technology [tris(pyrrolidino)phosphoramide] can allow for multigram-scale synthesis of pharmaceutically relevant building blocks. We show how these conditions have a very high level of functional-group tolerance relative to classical electrochemical and chemical dissolving-metal reductions. Finally, we demonstrate that the same electrochemical conditions can be applied to other dissolving metal–type reductive transformations, including McMurry couplings, reductive ketone deoxygenations, and epoxide openings.

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X-ray absorption near-edge structure (XANES) is commonly used to probe the oxidation state of metal-containing nanomaterials; however, as the particle size in the material drops below a few nanometers, it becomes important to consider inherent size effects on the electronic structure of the materials. In this paper, we analyze a series of size-selected Pt n /SiO2 samples, using X-ray photoelectron spectroscopy (XPS), low energy ion scattering, grazing-incidence small-angle X-ray scattering, and XANES. The oxidation state and morphology are characterized both as-deposited in UHV, and after air/O2 exposure and annealing in H2. The clusters are found to be stable during deposition and upon air exposure, but sinter if heated above ∼150 °C. XANES shows shifts in the Pt L3 edge, relative to bulk Pt, that increase with decreasing cluster size, and the cluster samples show high white line intensity. Reference to bulk standards would suggest that the clusters are oxidized; however, XPS shows that they are not. Instead, the XANES effects are attributable to development of a band gap and localization of empty state wave functions in small clusters.

We present a combined experimental/theoretical study of Pt n /SiO 2 and Pt n Sn x /SiO 2 (n = 4, 7) model catalysts for the endothermic dehydrogenation of hydrocarbons, using the ethylene intermediate as a model reactant. Mass-selected Pt n clusters were deposited onto amorphous SiO 2 /Si(100) to make the Pt n SiO 2 model catalysts. To produce Pt n Sn x clusters, size-selected Pt n was used to seed selective deposition of Sn on Pt via a self-limiting H 2 / SnCl 4 /H 2 reaction sequence. Model catalysts were analyzed using C 2 D 4 and CO temperature-programmed desorption (TPD), lowenergy ion scattering (ISS), X-ray photoelectron spectroscopy (XPS), plane wave density functional theory (DFT) global optimization combined with a statistical mechanical description of the catalytic interface, and a DFT mechanistic study. Supported pure Pt n clusters are found to be highly active toward dehydrogenation of C 2 D 4 , quickly deactivating due to a combination of carbon deposition and sintering, resulting in loss of accessible Pt sites. Addition of Sn to Pt n clusters results in the complete suppression of C 2 D 4 dehydrogenation and carbon deposition and also stabilizes the clusters against thermal sintering. Theory shows that both systems have thermal access to a multitude of cluster structures and adsorbate configurations that form a statistical ensemble. While Pt 4 /SiO 2 clusters bind ethylene in both di-σ-and π-bonded configurations, Pt 4 Sn 3 /SiO 2 binds C 2 H 4 only in the π mode, with di-σ bonding suppressed by a combination of electronic and geometric features of the PtSn clusters. Dehydrogenation reaction profiles on the accessible cluster isomers were calculated using the climbing image nudged elastic band (CI-NEB) method. Dehydrogenation of diσ-bound ethylene is computed to dominate and is suppressed by Sn addition, in agreement with the experiments. DFT indicates that, after Sn alloying, the barrier for ethane-to-ethylene conversion is lower than that for unwanted ethylene dehydrogenation.

An atomic layer deposition process is used to modify size-selected Pt7/alumina model catalysts by Sn addition, both before and after Pt7 cluster deposition. Surface science methods are used to probe the effects of Sn-modification on the electronic properties, reactivity, and morphology of the clusters. Sn addition, either before or after cluster deposition, is found to strongly affect the binding properties of a model alkene, ethylene, changing the number and type of binding sites, and suppressing decomposition leading to carbon deposition and poisoning of the catalyst. Density functional theory on a model system, Pt4Sn3/alumina, shows that the Sn and Pt atoms are mixed, forming alloy clusters with substantial electron transfer from Sn to Pt. The presence of Sn also makes all the thermally accessible structures closed shell, such that ethylene binds only by π-bonding to a single Pt atom. The Sn-modified catalysts are quite stable in repeated ethylene temperature programmed reaction experiments, suggesting that the presence of Sn also reduces the tendency of the sub-nano clusters to undergo thermal sintering.