Direct C-C Double Bond Cleavage of Alkenes Enabled by Highly Dispersed Cobalt Catalyst and Hydroxylamine.

The utilization of a single-atom catalyst to break C-C bonds merges the merits of homogeneous and heterogeneous catalysis and presents an intriguing pathway for obtaining high-value-added products. Herein, a mild, selective, and sustainable oxidative cleavage of alkene to form oxime ether or nitrile was achieved by using atomically dispersed cobalt catalyst and hydroxylamine. Diversified substrate patterns, including symmetrical and unsymmetrical alkenes, di- and tri-substituted alkenes, and late-stage functionalization of complex alkenes were demonstrated. The reaction was successfully scaled up and demonstrated good performance in recycling experiments. The hot filtration test, catalyst poisoning and radical scavenger experiment, time kinetics, and studies on the reaction intermediate collectively pointed to a radical mechanism with cobalt/acid/O2 promoted C-C bond cleavage as the key step.

Giant photonic spin Hall effect induced by hyperbolic shear polaritons.

Recently, broken symmetry within crystals has been attracting tremendous research interest since it can be utilized to effectively manipulate the propagation of photons. In particular, low-symmetry Bravais crystals can support hyperbolic shear polaritons (HShPs), holding great promise for technological upgrading in the emerging research area of spinoptics. Herein, an Otto-type multilayer structure consisting of a KRS5 prism, a sensing medium, and monoclinic ß-Ga2O3 crystals is designed to ameliorate the photonic spin Hall effect (PSHE). The surface of ß-Ga2O3 is the monoclinic (010) plane (x-y plane). We show that giant spin Hall shifts with three (or two) orders of magnitude of the incident wavelength can be obtained in the in-plane (or transverse) directions. The azimuthal dispersions of photonic spin Hall shifts present non-mirror-symmetric patterns upon tuning the rotation angle of ß-Ga2O3 around the z-axis in the plane. All of these exotic optical properties are closely correlated with the broken crystal lattice symmetry and the incurred excitation of HShPs in monoclinic ß-Ga2O3 crystals. By virtue of the remarkably enhanced PSHE, our proposed Otto-type multilayer structure shows a superior biosensing performance in which the maximum sensitivity is two orders of magnitude larger than that of previously reported PSHE biosensors based on two-dimensional materials. In addition, the optimized physical and structural parameters including the incident angle, excitation wavelength, azimuth angle and doping concentration of ß-Ga2O3, thickness and refractive index of sensing medium are also investigated and presented. This work unequivocally confirms the strong influence of crystal symmetry on the PSHE, providing important insights into understanding the rich modulation of spin-orbit interactions of light via shear polaritons and therefore facilitating potential applications in photoelectronic devices.

Atomically Dispersed Co-N/C Catalyst for Divergent Synthesis of Nitrogen-Containing Compounds from Alkenes.

Alkene functionalization with a single-atom catalyst (SAC) which merges homogeneous and heterogeneous catalysis is a fascinating route to obtain high-value-added molecules. However, C-N bond formation of alkene with SAC is still unexplored. Herein, a bimetal-organic framework-derived Co-N/C catalyst with an atomically dispersed cobalt center is reported to show good activity of chemoselective aziridination/oxyamination reactions from alkene and hydroxylamine, and late-stage functionalization of complex alkenes and diversified synthetic transformations of the aziridine product further expand the utility of this method. Moreover, this system proceeds without external oxidants and exhibits mild, atom-economic, and recyclable characters. Detailed spectroscopic characterizations and mechanistic studies revealed the structure of the catalytic center and possible intermediates involved in the mechanism cycle.

Core-Shell Nano-Cobalt Catalyzed Chemoselective Reduction of N-Heteroarenes with Ammonia Borane.

An easily prepared core-shell heterogeneous nanocobalt catalyst was reported, which could achieve selective reduction of N-heteroarenes with ammonia borane under mild conditions and ambient atmosphere. Various quinoline, quinoxaline, naphthyridine, isoquinoline, acridine, and phenanthroline derivatives were hydrogenated with high selectivity and efficiency. Notably, substrates bearing sensitive functional groups under molecular hydrogen reduction conditions, such as cyano, ester, and halogens were well tolerated by the catalytic system. Moreover, with our novel method several bioactive molecules were prepared. Also, this catalyst could be applied in the liquid organic hydrogen storage system by reversible hydrogenation and dehydrogenation of heteroarene in high efficiencies.

Visible-light-promoted acyl radical cascade reaction for accessing acylated isoquinoline-1,3(2H,4H)-dione derivatives.

A visible-light-promoted decarboxylative acyl radical acylation/cyclization cascade reaction of N-methacryloylbenzamides for accessing acylated isoquinoline-1,3(2H,4H)-dione derivatives was described. In this report, α-keto acids were used for generating acyl radicals and inducing radical acylations. This protocol features mild reaction conditions, operational practicality and a broad substrate scope.

Visible-light induced decarboxylative alkylation of quinoxalin-2(1H)-ones at the C3-position.

A simple and efficient method for the visible light induced direct carbon alkylation of quinoxalin-2(1H)-ones at the C3 position is described. This protocol employs cheap and readily available phenyliodine(iii) dicarboxylates as the alkylation reagents to conduct decarboxylative radical coupling reaction with quinoxalin-2(1H)-ones. The process exhibits excellent compatibility to functional groups and provides a convenient and selective access to various 3-alkylquinoxalin-2(1H)-ones in good yields.

Chinese herbal bath therapy for the treatment of uremic pruritus: meta-analysis of randomized controlled trials.

BACKGROUND: Chinese herbal bath therapy (CHBT) is a traditional external therapy that has been used for the treatment of uremic pruritus (UP) in China. We conducted a meta-analysis to evaluate the efficacy and safety of CHBT for UP. METHODS: We searched seven databases for studies published since database inception to September 1, 2018. Randomized trials evaluating CHBT for UP were collected. The therapeutic effects of CHBT were measured by the pruritus level (via the visual analogue scale (VAS) or the symptom score scale) and the total effective rate. We combined studies using mean difference (MD) for continuous outcomes and using risk ratio for dichotomous data, both with 95% confidence intervals. RevMan V.5.3 software was used to assess the data reported and perform the meta-analysis. RESULTS: Seventeen articles including 970 patients were identified. All participants were haemodialysis (HD) patients. CHBT is administered by immersing the whole body in a prepared herbal water bath. On average, an herbal bath prescription included 11 Chinese herbs. The mean treatment duration was 4.7 weeks. Compared with basic treatment (HD or haemoperfusion (HP)) and adding a control of sham CHBT, clear hot water bath, or calamine lotion, CHBT plus basic treatment reduced the VAS score (MD = - 2.38; 95% confidence intervals [CI], - 3.02 to - 1.74; P < 0.00001) and the symptom score (MD = - 8.42; 95% confidence intervals [CI], - 12.47 to - 4.36; P < 0.00001) and had a higher total effectiveness rate (risk ratio [RR] = 1.46; 95% CI, 1.31 to 1.63; P < 0.00001). CONCLUSIONS: In conclusion, CHBT could be a complementary therapy for improving pruritic symptoms in uraemia patients. More rigorously designed, multicentre, prospective RCTs are warranted to further identify the efficacy and safety of CHBT. TRIAL REGISTRATION: Systematic review registration: [PROSPERO registration: CRD42018108506 ].