Phosphine Oxide Porous Organic Polymers Incorporating Cobalt(II) Ions: Synthesis, Characterization, and Investigation of H2 Production

Facile Hydrogenolysis of Sugars to 1,2-Glycols by Ru@PPh3/OPPh3 Confined Large-Pore Mesoporous Silica

Tandem hydrogenation vis-à-vis hydrogenolysis of xylose to 1,2-glycols remains a major challenge. Although one-pot conversion of xylose to 1,2-glycols requires stringent conditions, a sustainable approach would be quite noteworthy. We have developed a microwave route for the one-pot conversion of pentose (C5) and hexose (C6) sugars into glycol and hexitol, without pressurized hydrogen reactors. A pronounced hydrogenolysis of sugars to glycols is observed by Ru single atom (SA) on triphenylphosphine/phosphine oxide-modified silica (Ru@SiP), in contrast to Ru SA on pristine (Ru@SiC) and 3-aminopropyl-modified silica (Ru@SiN). A promising "ligand effect" was observed through phosphine modification of silica that presents a 70% overall yield of all reduced sugars (xylitol + glycols) from a 99% conversion of xylose with Ru@SiP. A theoretical study by DFT depicts an electronic effect on Ru-SA by triphenylphosphine that promotes the catalytic hydrogenolysis of sugars under mild conditions. Hence, this research represents an important step for glycols from biomass-derived sources.

C- and N-Phosphorylated Enamines-An Avenue to Heterocycles: NMR Spectroscopy

The review presents extensive data (from the works of the author and literature) on the structure of C- and N-chlorophosphorylated enamines and the related heterocycles obtained by multipulse multinuclear ¹H, ¹³C, and ³¹P NMR spectroscopy. The use of phosphorus pentachloride as a phosphorylating agent for functional enamines enables the synthesis of various C- and N-phosphorylated products that are heterocyclized to form various promising nitrogen- and phosphorus-containing heterocyclic systems. ³¹P NMR spectroscopy is the most convenient, reliable and unambiguous method for the study and identification of organophosphorus compounds with different coordination numbers of the phosphorus atom, as well as for the determination of their Z- and E-isomeric forms. An alteration of the coordination number of the phosphorus atom in the phosphorylated compounds from 3 to 6 leads to a drastic screening of the ³¹P nucleus from about +200 to -300 ppm. The unique structural features of nitrogen-phosphorus-containing heterocyclic compounds are discussed.

Electrochemically Oxidative Phosphating of Aldehydes and Ketones

Disclosed herein is the first protocol for the electrochemically oxidative phosphating of aldehydes and ketones to generate α-hydroxyphosphine oxides with diphenylphosphine as the phosphine source. Various phosphating products containing P-C bonds are basically assembled in modest to excellent yields. This electrochemical phosphating was achieved by utilizing a simple undivided cell with foam nickel electrodes at room temperature without the addition of any oxidant or metal catalyst. The prepared α-hydroxyphosphine oxides possess potential application in pharmacological research.

Combining Polymerization and Templating toward Hyper-Cross-Linked Poly(propargyl aldehyde)s and Poly(propargyl alcohol)s for Reversible H2O and CO2 Capture and Construction of Porous Chiral Networks

Two series of hyper-cross-linked microporous polyacetylene networks containing either -[CH=C(CH=O)]- or -[CH=C(CH₂OH)]- monomeric units are reported. Networks are prepared by chain-growth copolymerization of acetal-protected propargyl aldehyde and acetal-protected propargyl alcohol with a 1,3,5-triethynylbenzene cross-linker followed by hydrolytic deprotection/detemplating. Deprotection not only liberates reactive CH=O and CH₂OH groups in the networks but also modifies the texture of the networks towards higher microporosity and higher specific surface area. The final networks with CH=O and CH₂OH groups attached directly to the polyene main chains of the networks have a specific surface area from 400 to 800 m²/g and contain functional groups in a high amount, up to 9.6 mmol/g. The CH=O and CH₂OH groups in the networks serve as active centres for the reversible capture of CO₂ and water vapour. The water vapour capture capacities of the networks (up to 445 mg/g at 297 K) are among the highest values reported for porous polymers, making these materials promising for cyclic water harvesting from the air. Covalent modification of the networks with (R)-(+)-3-aminopyrrolidine and (S)-(+)-2-methylbutyric acid enables the preparation of porous chiral networks and shows networks with CH=O and CH₂OH groups as reactive supports suitable for the anchoring of various functional molecules.

Carbonaceous FexP Synthesized via Carbothermic Reduction of Dephosphorization Slag as Hydrogen Evolution Catalyst for Water Splitting

Developing the high-efficiency and cheap non-noble catalysts towards hydrogen evolution reaction (HER) is of significance for water splitting. Herein, for the first time, we report a simple method of acid leaching combined with carbothermic reduction with dephosphorization slag to construct a carbonaceous FexP/C catalyst. In alkaline medium, the corresponding overpotential when the output current density was 10 mA cm−2 (η10) was only 145 mV. Additionally, there was no obvious attenuation after 3000 cycles, which showed significantly better activity and stability than that of non-carbonaceous FexP catalysts prepared by gas–solid phosphating. The structure and composition of FexP/C were characterized by X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy, and inductively coupled plasma atomic emission spectrometer. The electrochemical properties of the electrode were evaluated by cyclic voltammetry, linear scanning voltammetry, electrochemical impedance spectroscopy, and cyclic stability. The results showed that the prepared FexP/C was composed of FeP-Fe2P mixed nanocrystals supported on amorphous carbon. Compared with FexP, the synergistic catalysis of the FeP and Fe2P phases as well as the interactive support effect between the FeP-Fe2P mixed nanocrystals and the amorphous carbon support will attribute the rich active sites for electrocatalytic reaction and reduce the charge transfer resistance. Thus, FexP/C has good hydrogen evolution activity and stability. Overall, the preparation of catalysts with high additional value based on dephosphorization slag was preliminarily explored.