Herein, we describe the redox chemistry of bi- and mononuclear α-diimine-Mn­(CO)3 complexes with an internal proton source in close proximity to the metal centers and their catalytic activity in the electrochemically driven CO2 reduction reactions. In order to address the impact of the two metal sites and of the proton source, we investigate a binuclear complex with phenol moiety, 1, a binuclear Mn complex with methoxyphenol unit instead, 2, and the mononuclear analogue with a phenol unit, 3. Spectroelectrochemical investigation of the complexes in dmf under a nitrogen atmosphere indicates that 1 and 3 undergo a reductive H2 formation forming [Mn2(H–1L1)­(CO)6Br] and [Mn­(H–1L3)­(CO)3], respectively, which is redox neutral for the complex and equivalent to a deprotonation of the phenol unit. The reaction likely proceeds via internal proton transfer from the phenol moiety to the reduced metal center forming a Mn–H species. 2 dimerizes during reduction, forming [Mn2(L2)­(CO)6]2, but 1 and 3 do not. Reduction of 1, 2, and 3 is accompanied by bromide loss, and the final species represent [Mn2(H–1L1)­(CO)6]3–, [Mn2(L2)­(CO)6]2–, and [Mn­(H–1L3)­(CO)3]2–, respectively. 1 and 2 are active catalysts in the electrochemical CO2 reduction reaction, whereas 3 decomposes quickly under an applied potential. Thus, the second redox active unit is crucial for enhanced stability. The proton relay in 1 alters the kinetics for the 2H+/2e– reduced products of CO2 in dmf/water mixtures. For 2, CO is the only product, whereas formate and CO are formed in similar amounts, 40% and 50%, respectively, in the presence of 1. Thus, the reaction rate for the internal proton transfer from the phenol moiety to the metal center forming the putative Mn–H species and subsequent CO2 insertion as well as the reaction rate of the reduced metal center with CO2 forming CO are similar. The overpotential with regard to the standard redox potential of CO2 to CO and the observed overall rate constant for catalysis at scan rates of 0.1 V s–1 are higher with 1 than with 2, that is, the OH group is beneficial for catalysis due to the internal proton transfer.

Molecular catalysts can promote ammonia oxidation, providing mechanistic insights into the electrochemical N 2 cycle for a carbon-free fuel economy. We report the ammonia oxidation activity of carbon anodes functionalized with the oligomer {[Ru II (bda-κ-N 2 O 2 )(4,4′bpy)] 10 (4,4′-bpy)}, Rubda-10, where bda is [2,2′-bipyridine]-6,6′dicarboxylate and 4,4′-bpy is 4,4′-bipyridine. Electrocatalytic studies in propylene carbonate demonstrate that the Ru-based hybrid anode used in a 3-electrode configuration transforms NH 3 to N 2 and H 2 in a 1:3 ratio with near-unity faradaic efficiency at an applied potential of 0.1 V vs Fc +/0 , reaching turnover numbers of 7500. X-ray absorption spectroscopic analysis after bulk electrolysis confirms the molecular integrity of the catalyst. Based on computational studies together with electrochemical evidence, ammonia nucleophilic attack is proposed as the primary pathway that leads to critical N−N bond formation.

Data sharing is central to the rapid translation of research into advances in clinical medicine and public health practice. In the context of COVID-19, there has been a rush to share data, marked by an explosion of population- and discipline-specific resources for collecting, curating, and disseminating participant-level data. We present a comprehensive overview of COVID-19-related platforms and registries that harmonize and share participant-level clinical, OMICs, and imaging data and metadata, and describe how these initiatives map to best practice for ethical, equitable, and FAIR management of data resources. Data sharing resources were concentrated in high income countries and siloed by comorbidity, body system, and data type. Resources for sharing clinical data were less FAIR than those for sharing OMICs or imaging data. We review gaps and redundancies in COVID-19 data sharing efforts and outline recommendations to build on existing synergies and align with frameworks for effective and equitable data reuse.

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