The conventional homogeneous catalysts for the enantioselective hydrogenation or transfer hydrogenation of ketones are based on platinum metals and, in particular, ruthenium. This method provides valuable enantiopure alcohols for the fine chemical industries. This tutorial review summarizes recent successes in replacing expensive and toxic ruthenium in these catalysts with “greener” iron substitutes including my lab’s recent progress in this area using iron complexes containing readily-prepared tetradentate ligands. It will enlighten chemists interested in homogeneous catalysis and asymmetric synthesis.

Making chemistry less precious: Much of modern chemistry relies on catalysis by precious metals such as platinum, palladium, and rhodium. By contrast, more abundant metals such as iron and copper suffice in biochemistry. Bullock et al. review the opportunities presented from the study of enzymes to shift the balance in synthetic catalysts further toward the use of these abundant metals. Whether by modifying the enzymes themselves or by designing ligand and support architectures that take advantage of the cheaper metals' characteristic electron transfer properties, recent work points toward substantial progress. Science , this issue p. eabc3183

The extraction and combustion of fossil natural gas, consisting primarily of methane, generates vast amounts of greenhouse gases that contribute to climate change. However, as a result of recent research efforts, “solar methane” can now be produced through the photocatalytic conversion of carbon dioxide and water to methane and oxygen. This approach could play an integral role in realizing a sustainable energy economy by closing the carbon cycle and enabling the efficient storage and transportation of intermittent solar energy within the chemical bonds of methane molecules. In this article, we explore the latest research and development activities involving the light-assisted conversion of carbon dioxide to methane.