A "Pre-Division Metal Clusters" Strategy to Mediate Efficient Dual-Active Sites ORR Catalyst for Ultralong Rechargeable Zn-Air Battery.

To conquer the bottleneck of sluggish kinetics in cathodic oxygen reduction reaction (ORR) of metal-air batteries, catalysts with dual-active centers have stood out. Here, a "pre-division metal clusters" strategy is firstly conceived to fabricate a N,S-dual doped honeycomb-like carbon matrix inlaid with CoN4 sites and wrapped Co2 P nanoclusters as dual-active centers (Co2 P/CoN4 @NSC-500). A crystalline {CoII 2 } coordination cluster divided by periphery second organic layers is well-designed to realize delocalized dispersion before calcination. The optimal Co2 P/CoN4 @NSC-500 executes excellent 4e- ORR activity surpassing the benchmark Pt/C. Theoretical calculation results reveal that the CoN4 sites and Co2 P nanoclusters can synergistically quicken the formation of *OOH on Co sites. The rechargeable Zn-air battery (ZAB) assembled by Co2 P/CoN4 @NSC-500 delivers ultralong cycling stability over 1742 hours (3484 cycles) under 5 mA cm-2 and can light up a 2.4 V LED bulb for ≈264 hours, evidencing the promising practical application potentials in portable devices.

Nonepimerizing Alkylation of H-P Species to Stereospecifically Generate P-Stereogenic Phosphine Oxides: A Shortcut to Bidentate Tertiary Phosphine Ligands.

The secondary RP-(-)-menthyl alkylphosphine oxide was confirmed as configurationally stable toward base and was used in base-promoted alkylation, stereospecifically affording P-retained bis or functional tertiary phosphine oxides in excellent yields. The alkylated products were deoxygenated using oxalyl chloride followed by ZnCl2-NaBH4 to form P-inversed bidentate phosphine boranes in high stereoselectivities.

Preparation of Optically Pure Tertiary Phosphine Oxides via the Addition of P-Stereogenic Secondary Phosphine Oxide to Activated Alkenes.

Functionalized P,C-stereogenic tertiary phosphine oxides were prepared by the addition of (RP)-menthyl phenylphosphine oxide to activated olefins, in high drP and drC, and were isolated in excellent yields. The reaction was readily catalyzed by Ca(OH)2 or occurred with gentle heating. A wide range of substrates, including vinyl ketones, esters, nitriles, and nitro alkenes, can be used in the reaction.

Double Asymmetric Induction During the Addition of (RP)-Menthyl Phenyl Phosphine Oxide to Chiral Aldimines.

P,C-Stereogenic α-amino phosphine oxides were prepared from the addition of (RP )-menthyl phenyl phosphine oxide to chiral aldimines under neat condition at 80 °C in up to 91:9 drC and 99% yields. The diastereoselectivity was mainly induced by chiral phosphorus that showed matched or mismatched induction with (S)- or (R)-aldimines, respectively.

Tandem addition of nucleophilic and electrophilic reagents to vinyl phosphinates: the stereoselective formation of organophosphorus compounds with congested tertiary carbons.

Carbon anions formed via the addition of Grignard reagents to SP-vinyl phosphinates were modified with electrophilic reagents to afford organophosphorus compounds with diverse carbon skeletons. The electrophiles included acids, aldehydes, epoxy groups, chalcogens and alkyl halides. When alkyl halides were used, bis-alkylated products were afforded. Substitution reactions or polymerization occurred when the reaction was applied to vinyl phosphine oxides.

Nucleophilic Substitution of P-Stereogenic Chlorophosphines: Mechanism, Stereochemistry, and Stereoselective Conversions of Diastereomeric Secondary Phosphine Oxides to Tertiary Phosphines.

A diastereomeric mixture of secondary phosphine oxide is stereospecifically converted to chlorophosphine salt by treatment with oxalyl chloride, which stereoselectively affords P-inverted or retained tertiary phosphines, depending on the substitution with aliphatic or aromatic Grignard reagents, respectively, in high to 99% yield and 99:1 dr. The repulsion of π-electron on aryl to lone electron pair on phosphorus is proposed for the P-retained substitution.