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High photoinduced charge-carrier-separation efficiency plays a crucial factor in determining the photocatalytic activities of photocatalysts, and it remains challenging to steer the charge separation in an accurate manner. Herein, we address this important challenge by growing the Co2P cocatalyst onto the edges of black phosphorus (BP) nanosheets to craft Co–P bonds in the Co2P/BP nanosheets photocatalyst. As demonstrated by the photocurrent measurement and first-principle calculation, the Co–P bonds acting to faciliate atomic-level charge-flow steering can improve the photogenerated charge-carrier transfer between BP nanosheets and the Co2P cocatalyst, resulting in the improved photocatalytic performance of the Co2P/BP photocatalyst for H2 generation. As expected, the photocatalytic H2 generation rate of the Co2P/BP nanosheets photocatalyst is 39.7 times greater than that of bare BP nanosheets. Moreover, the Co2P grown on the edges of BP nanosheets inhibits the degradation of the BP nanosheets, resulting in its good stability for photocatalytic H2 production.

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Spirooxindole epoxides undergo smooth rearrangement either under photosensitization conditions or under Lewis acid catalysis to give different products. The photosensitized rearrangement of spirooxindole epoxides leads to 3‐acyl‐2‐indolones, such as spiro[cycloalkane‐1,3′‐indolin]‐2,2′‐diones, by cleavage of the Cα–O bond followed by alkyl migration. The SnCl4‐catalyzed rearrangement of spirooxindole epoxides gives 4,4‐dialkylquinolin‐2,3‐diones, such as spiro[cycloalkane‐1,4′‐quinolin]‐2′,3′‐diones, by cleavage of the Cβ–O bond followed by aryl migration.

Herein, we present a stable water-soluble cobalt complex supported by a dianionic 2,2'-([2,2'bipyridine]-6,6'-diyl)bis(propan-2-ol) ligand scaffold, which is a rare example of a high-oxidation species, as demonstrated by structural, spectroscopic and theoretical data. Electron paramagnetic resonance (EPR) spectroscopy and magnetic susceptibility measurements revealed that the Co IV center of the mononuclear complex in the solid state resides in the high spin state (sextet, S = 5/2). The complex can effectively catalyze water oxidation via a single-site water nucleophilic attack pathway with an overpotential of only 360 mV in a phosphate buffer with a pH of 6. The key intermediate toward water oxidation was speculated based on theoretical calculations and was identified by in situ spectroelectrochemical experiments. The results are important regarding the accessibility of high-oxidation state metal species in synthetic models for achieving robust and reactive oxidation catalysis.

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