Combined theoretical and experimental studies have explained the mechanism of Pd-catalyzed δ-C(sp^(3))-H arylation of primary amines. Instead of the monomeric Pd mechanism, our research unveils that all steps includi...Combined theoretical and experimental studies have explained the mechanism of Pd-catalyzed δ-C(sp^(3))-H arylation of primary amines. Instead of the monomeric Pd mechanism, our research unveils that all steps including C–H activation, oxidative addition, and reductive elimination take place via the heterodimeric Pd–Ag intermediates and transition states. Experimentally, the active heterodimeric Pd–Ag species were detected by mass spectrometry, which further confirms the proposed heterodimeric mechanism. Insight gained through this study reveals the synergistic manner of palladium catalysis and silver(Ⅰ)additives in native NH;-directed C–H activation and C–C coupling reactions.展开更多
Effects of Ag addition on the microsmactures, aging characteristics, tensile properties, electrochemical properties, and intergranu- lar corrosion （IGC） properties of Al 1.1Mg-0.8Si-0.9Cu-0.35Mn4）.02Ti alloy were i...Effects of Ag addition on the microsmactures, aging characteristics, tensile properties, electrochemical properties, and intergranu- lar corrosion （IGC） properties of Al 1.1Mg-0.8Si-0.9Cu-0.35Mn4）.02Ti alloy were investigated using scanning electronic microscopy and transmission electronic microscopy. The aging process of Al-Mg-Si-Cu alloys was accelerated by the addition of Ag. The strength of peak-aged Al-Mg-Si-Cu alloys was enhanced by Ag addition because of the high density of β＂- and L-phase age-hardening precipitates. The corrosion performance of the Al-Mg-Sii-Cu alloy is closely related to the aging conditions and is independent of the Ag content. The IGC susceptibility is serious in the peak-aged alloy because of the continuous distribution of Cu-rich Q-phase precipitates along grain boun- daries. Ag addition reduces the size of the grain-boundary-precipitate Q phase and the width of the precipitate-free zone and thus results in decreased IGC susceptibility of Al-Mg-Si Cu alloys.展开更多
基金supported by the Tianjin University and the National Natural Science Foundation of China (Nos. 22073067 and 21673156)。
文摘Combined theoretical and experimental studies have explained the mechanism of Pd-catalyzed δ-C(sp^(3))-H arylation of primary amines. Instead of the monomeric Pd mechanism, our research unveils that all steps including C–H activation, oxidative addition, and reductive elimination take place via the heterodimeric Pd–Ag intermediates and transition states. Experimentally, the active heterodimeric Pd–Ag species were detected by mass spectrometry, which further confirms the proposed heterodimeric mechanism. Insight gained through this study reveals the synergistic manner of palladium catalysis and silver(Ⅰ)additives in native NH;-directed C–H activation and C–C coupling reactions.
基金financially supported by the National Natural Science Foundation of China (No. 51574076)
文摘Effects of Ag addition on the microsmactures, aging characteristics, tensile properties, electrochemical properties, and intergranu- lar corrosion （IGC） properties of Al 1.1Mg-0.8Si-0.9Cu-0.35Mn4）.02Ti alloy were investigated using scanning electronic microscopy and transmission electronic microscopy. The aging process of Al-Mg-Si-Cu alloys was accelerated by the addition of Ag. The strength of peak-aged Al-Mg-Si-Cu alloys was enhanced by Ag addition because of the high density of β＂- and L-phase age-hardening precipitates. The corrosion performance of the Al-Mg-Sii-Cu alloy is closely related to the aging conditions and is independent of the Ag content. The IGC susceptibility is serious in the peak-aged alloy because of the continuous distribution of Cu-rich Q-phase precipitates along grain boun- daries. Ag addition reduces the size of the grain-boundary-precipitate Q phase and the width of the precipitate-free zone and thus results in decreased IGC susceptibility of Al-Mg-Si Cu alloys.
