Spotlights on Recent JACS Publications

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Ruthenium is an element commonly used for catalytic oxidation of water and organic compounds. The reactivity of this oxidant is widely assumed to be associated with key, high-valent Ru^V−oxo intermediates. However, the highly reactive nature of these species has prevented their isolation and further investigation. More generally, oxo and oxyl species have been proposed to be critical in oxidation catalysis, but not many well-characterized examples are available.

[FeFe] hydrogenases are highly efficient enzymes for both hydrogen evolution and uptake. They are key enzymes in many algae and bacteria, and with their high efficiency they are viewed as promising catalysts for the hydrogen economy. However, the catalytic mechanisms remained controversial—particularly the nature of the one-electron reduced and two-electron super-reduced intermediate states, H_redH⁺ and H_sredH⁺. Two models existed: one in which these two states contain a bridging carbon monoxide ligand, and another model in which the CO ligand is replaced by a bridging hydride ligand.

The ability to control the three-dimensional arrangement of metal nanoparticles opens the door to the creation of nanoparticle structures with properties ideal for applications in nanoelectronics, photonics, optics, catalysis, and more. A popular method for directing the assembly of nanoparticles into ordered structures involves functionalizing the surface with a dense shell of nucleic acids that bond to complementary strands on other particles to arrange particles with well-defined spacing. While the approach offers researchers a high level of structural control, DNA-mediated assembly faces certain limitations. For example, assembly is restricted to aqueous conditions, DNA derivatives can be costly, and it can be difficult to scale-up the approach.

Biologically responsive dyes are valuable for laboratory research and biomedical diagnostics because they can reveal what is happening inside living tissue. While some such dyes exist, researchers can always use more insight into new biochemical processes and better methods of synthesizing the dyes. Now, Gary J. Richards, Jonathan Hill, and co-workers have developed a new compound that can react to both acids and bases and emits light in a band that can pass through tissue (DOI: 10.1021/jacs.9b10952).

Water-splitting reactions, which produce hydrogen and oxygen, are perennial candidates for cheap, renewable energy, but finding efficient, economical means to do this on a large scale has proven challenging. A recent computational study by Liangzhi Kou and colleagues identified a way to accelerate and fine-tune water-splitting using sunlight and a one-atom-thick layer of a silver-based catalyst, AgBiP₂Se₆ (DOI: 10.1021/jacs.9b11614).

This catalyst has two phases: one is ferroelectric and the other paraelectric. The ferroelectric phase has a higher capability of water oxidation and is suitable for oxygen production, but the paraelectric phase possesses a higher capability of water reduction and is suitable for hydrogen production in acidic environments. Before now, ferroelectricity had not been studied in the context of its effect on converting sunlight to chemical energy. Kou and co-workers’ calculations showed that the combination of the ultrathin layer and the ferroelectric polarization enhanced their catalyst’s ability to separate water into its elements and keep them from recombining.