A series of nucleophilic addition reactions and α-C–H substitution reactions of an imine-containing ligand 2-(2-((((1H-pyrrol-2-yl)methylene)amino)methyl)-1H-pyrrol-1-yl)-N,N-dimethylethan-1-amine (HL1) were reported. The reactions of HL1 with 0.5 and 2 equiv of nBu2Mg, respectively, gave two complexes of compositions [Mg(L1)2] (1) and [Mg2(L2)2] (2) (H2L2 = N-((1-(2-(dimethylamino)ethyl)-1H-pyrrol-2-yl)methyl)-1-(1H-pyrrol-2-yl)pentan-1-amine). The nucleophilic addition of nBu2Mg to the C═N bond of the HL1 ligand occurred in the process for the formation of 2. Treatment of HL1 with 2 and 1 equiv of nBuLi generated [Li2(L3)2] (3) (HL3 = 2-(2-(((1-(1H-pyrrol-2-yl)pentylidene)amino)methyl)-1H-pyrrol-1-yl)-N,N-dimethylethan-1-amine) and [Li2(L1)2] (4). An α-C–H substitution of the HC═NR moiety of the HL1 ligand triggered by nBuLi was discovered in the preparation of 3. The formation of 3 demonstrates a new concept for the C–C coupling that involved inert C–H bond activation of HC═NR skeleton. The reactions of HL1 with MeLi, sec-BuLi, and tert-BuLi, respectively, were also examined. The products for both the nucleophilic addition of organolithium reagents to the C═N bond and α-C–H substitution of the HC═NR moiety of the HL1 ligand were determined. The mechanisms for the formations of 2 and 3 were rationalized by DFT calculations. The hydroboration reactions catalyzed by 2 were investigated, and these reactions characterize ample substrate scope, very good yields, and high selectivity.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Bessere Resultate in der elektrokatalytischen Sauerstoffentwicklung könnten stabile Dimetall-organische Gerüste liefern, die von Y. Li, Y.-Q. Lan et al. in ihrer Zuschrift auf S. 9808 vorgestellt werden. Als Bild für das Metall-organische Gerüst (MOF) dient ein Zauberwürfel, in dem jedes Bruchstück einer MOF-Einheit mit Di- oder Monometallclustern entspricht. Für den Bildhintergrund wurde ein Meer als Symbol für die unerschöpfliche Rohstoffquelle der elektrokatalytischen Wasserspaltung gewählt.
Comprehensive Summary Herein, we report a novel heterogeneous photocatalyst for radical‐mediated oxidative oxysulfonylation of alkynes to β‐keto sulfones under environmentally benign conditions. The oxygen vacancy‐rich semiconductor Nb 2 O 5 (labeled as OVs‐N‐Nb 2 O 5 ) could efficiently catalyze a wide range of alkynes, especially for those bearing electron‐deficient substituents or internal alkynes, to their corresponding β‐keto sulfones in good to high yields with good tolerance of diverse functional groups under visible‐light illumination. The late‐stage modification of steroidal compounds and synthesis of bioactive molecules were also achieved via this procedure, highlighting its potential for practical applications. Meanwhile, the photocatalyst OVs‐N‐Nb 2 O 5 showed outstanding catalytic stability for successive recycles without appreciable loss in activity and selectivity. The critical role of oxygen vacancies on improving reaction activity and selectivity was clearly disclosed via control experiments and theoretical calculation.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Abstract The (photo)electrochemical N 2 reduction reaction (NRR) provides a favorable avenue for the production of NH 3 using renewable energy in mild operating conditions. Understanding and building an efficient catalyst with high NH 3 selectivity represents an area of intense interest for the early stages of development for NRR. Herein, we introduce a CoO x layer to tune the local electronic structure of Au nanoparticles with positive valence sites for boosting conversion of N 2 to NH 3 . The catalysts, possessing high average oxidation states (ca. 40 %), achieve a high NH 3 yield rate of 15.1 μg cm −2 h −1 and a good faradic efficiency of 19 % at −0.5 V versus reversible hydrogen electrode. Experimental results and simulations reveal that the ability to tune the oxidation state of Au enables the control of N 2 adsorption and the concomitant energy barrier of NRR. Altering the Au oxidation state provides a unique strategy for control of NRR in the production of valuable NH 3 .
Abstract The controllable synthesis of phosphorus (P) doped noble metal electrocatalysts with a well‐defined structure and composition has attracted sufficient attention in energy chemistry. In this study, atomic‐level P‐doped Pt nanodendrites (PtP NDs) with tunable composition and highly branched architecture are successfully prepared by post‐phosphating reaction of sodium hypophosphite monohydrate at room temperature. Due to its electrophilic properties, P effectively regulates the electronic structure of the d‐orbitals of Pt. The charge change induced by P on a local scale can effectively regulate the selective adsorption of electrocatalytic reaction intermediates. The electrocatalytic results show that the η 10 value of PtP NDs in hydrogen evolution reaction is only 13.3 mV, and the mass activity of PtP NDs in methanol oxidation reaction is 4.2 A mg −1 , which is 3.8 times larger than that of commercial Pt/C. Most importantly, the atomic‐level P doping greatly improves the stability of PtP NDs, which is crucial to facilitating the catalysts’ commercialization process.
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