Closing Kok's cycle of nature's water oxidation catalysis.

The MnCaO cluster in photosystem II catalyzes water splitting through the S state cycle (i = 0-4). Molecular O is formed and the natural catalyst is reset during the final S → (S) → S transition. Only recently experimental breakthroughs have emerged for this transition but without explicit information on the S-state reconstitution, thus the progression after O release remains elusive.

Alternative Mechanism for O Formation in Natural Photosynthesis via Nucleophilic Oxo-Oxo Coupling.

O formation in photosystem II (PSII) is a vital event on Earth, but the exact mechanism remains unclear. The presently prevailing theoretical model is "radical coupling" (RC) involving a Mn(IV)-oxyl unit in an "open-cubane" MnCaO cluster, which is supported experimentally by the S state of cyanobacterial PSII featuring an additional Mn-bound oxygenic ligand. However, it was recently proposed that the major structural form of the S state of higher plants lacks this extra ligand, and that the resulting S state would feature instead a penta-coordinate dangler Mn(V)=oxo, covalently linked to a "closed-cubane" MnCaO cluster.

Water-in-salt electrolytes made saltier by Gemini ionic liquids for highly efficient Li-ion batteries.

The water-in-salt electrolytes have promoted aqueous Li-ion batteries to become one of the most promising candidates to overcome safety concerns/issues of traditional Li-ion batteries. A simple increase of Li-salt concentration in electrolytes can successfully expand the electrochemical stability window of aqueous electrolytes beyond 2 V. However, necessary stability improvements require an increase in complexity of the ternary electrolytes.