A microwave-assisted, Cp*Co-catalyzed direct C-H activation/double C-N bond formation reaction of simple NH-sulfoximines with 1,4,2-dioxazol-5-ones to produce diverse thiadiazine-1-oxides is reported. The reaction tolerates a broad range of functional groups under external oxidant-free conditions and only releases CO and HO as the sole byproducts. The preliminary mechanistic studies revealed an electrophilic metalation pathway is likely involved in the reaction.

A direct oxidative cross-coupling between terminal alkynes and secondary phosphine oxides was developed. This approach provides an efficient way to construct alkynyl di(phenyl) phosphine oxides from basic materials, and in this process, the silver salts act as a key promoter.

COMMUNICATION This journal isAn environmental friendly direct oxidative amidation between methylarenes and free amines was developed. The aromatic amide could be prepared efficiently from raw chemicals by employing TBHP as the "green" oxidant with the co-catalysis of TBAI and FeCl 3 in water.

wurtzitane (ε-HNIW) in five pure solvents (ethyl acetate, N,N-dimethylformamide, acetonitrile, cyclohexanone, N-methylpyrrolidone) at temperatures ranging from 283.15 to 333.15 K at atmospheric pressure were measured by the isothermal method; meanwhile, the solubility behavior of ε-HNIW in four binary solvents (dichloromethane, chloroform, tetrachloromethane, and 1,2-dichloroethane mixed with various mole fractions of ethyl acetate, respectively) was experimentally studied by the equilibrium method at temperatures ranging from 283.15 to 323.15 K. The experimental data in pure solvents were correlated by the van't Hoff equation and modified Apelblat equation. It was found that both of them could obtain good correlation results according to relative average deviations, root-mean-square deviations, and correlation coefficients (R 2 ). The solubilities of ε-HNIW in binary solvents were correlated with the modified Apelblat equation, the combined nearly ideal binary solvent/Redlich−Kister (CNIBS/R-K) equation, and the Jouyban−Acree model. For the binary solvents studied, all of the models provide a satisfactory correlation.

To study the effect of the surface properties on the bending fatigue performance of heavy-duty gear steel, the authors of this paper used the ultrasonic surface rolling process (USRP) to strengthen 20Cr2Ni4A carburized gear steel. USRP is a novel technique in which the ultrasonic technology is incorporated into the concept of conventional deep rolling. In this study, we illustrated how the surface properties and cross-section mechanical property influence the three-point bending fatigue life of the samples before and after USRP treatment. At the same time, the predicted failure probability-stress-number of cycles (P-S-N) curve was drawn, and the fatigue fracture was analysed. The results show that the fatigue limit increased from 651.36 MPa to 918.88 MPa after USRP treatment. The fatigue source is mainly from the sample interior or surface scratches, and the fatigue performance is positively correlated with the results of the material surface roughness, surface residual stress and surface hardness. At the same time, combined with the change in the phase structure, dislocation structure, residual stress and hardness of the cross section of the material, it is found that the USRP process turns the steel into a gradient material with five layers. Finally, the coupling mechanism between the ultrasonic surface strengthening deformation layer and the carburized layer of 20Cr2Ni4A carburized gear steel is presented, and the grain structure distribution diagram of the section of the 20Cr2Ni4A model after surface strengthening treatment was simulated. The mechanism that influenced the fatigue performance after USRP treatment is explained from the perspectives of the surface and cross section of the samples.