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Selective deuteration of unactivated C(sp3)-H bonds is a highly attractive but challenging subject of research in pharmaceutical chemistry, material science and synthetic chemistry. Reported herein is a practical, highly selective and economical efficient hydrogen/deuterium (H/D) exchange of unactivated C(sp3)-H bonds by synergistic photocatalysis and hydrogen atom transfer (HAT) catalysis. With the easily prepared PMP-substituted amides as nitrogen-centered radical precursors, a wide range of structurally diverse amides can undergo predictable radical H/D exchange smoothly with inexpensive D2O as the sole deuterium source, giving rise to the distal tertiary, secondary and primary C(sp3)-H bonds selectively deuterated products in yields of up to 99% and excellent D-incorporations. In addition to precise monodeuteration, this strategy can also achieve multideuteration of the substrates contain more than one remote C(sp3)-H bond, which opens a method to address multi-functionalization of distal unactivated C(sp3)–H bonds. Deuteration of unactivated C(sp3)̵̵̵̵̵̵̵̵–H bonds is a simple route to deuterated compounds, of use in pharmaceutical chemistry, material science, and synthetic chemistry. Here, the authors describe a hydrogen/deuterium (H/D) exchange of remote unactivated C(sp3)̵̵̵̵̵̵̵̵–H bonds via photocatalysis, proceeding through hydrogen atom transfer. [ABSTRACT FROM AUTHOR]

The first-principal pseudopotential plane wave method based on density functional theory was used to calculate the geometrical structure, electronic structure, complex dielectric function, absorption coefficient and photoconductivity of Sc or Ce doped and co-doped CrSi2, respectively. The results show that the lattice constants of CrSi2 increase with the doping of Sc and Ce, and the values of bandgap decrease with the co-doping of Sc and Ce. The band gaps of Sc, Ce and co-doped CrSi2 decrease to 0. 245 eV, 0. 232 eV and 0. 198 eV, respectively. The Fermi level of doped CrSi2 moves to the low energy region and enters the valence band. Due to the major contribution of the 3d state electrons of Sc and 4f state electrons of Ce, the single Sc or Ce doped CrSi2 appears an impurity level below the conduction band. Sc-Ce co-doping makes CrSi2 transform into metal, and the electrical conductivity is improved obviously. After doping, the first dielectric peak of the imaginary part of the CrSi2 dielectric function increases and moves towards the direction of low energy, indicating that Sc or Ce doping enhances the optical transition intensity of CrSi2 in the low energy region, and great intensity is obtained when the CrSi2 is co-doped by Sc-Ce. The absorption edge of Sc or Ce doped CrSi2 redshifts in the low energy direction. The intrinsic CrSi2 hardly absorbs photons when the photon energy is greater than 21.6 eV, especially near higher photon energies at 31. 3 eV. The absorption ability of Sc doped and Sc-Ce co-doped CrSi2 increases, and the second absorption peak is formed near E = 31. 3 eV. The results show that doping Sc or Ce can improve the absorption of CrSi2 to infrared and higher energy photons. The photoconductivity of CrSi2 increases after doping in the low energy region of less than 3.91 eV. In the energy range of 20.01 eV < E <34.21 eV, the photoconductivity of intrinsic CrSi2 is zero, but the photoconductivity of the Sc and Ce doped CrSi2 is not zero. Doping broadens the optical response range of CrSi2. The results provide a theoretical basis for the application and design of CrSi2-based optoelectronic devices. [ABSTRACT FROM AUTHOR]

The first-principal pseudopotential plane wave method based on density functional theory was used to calculate the geometrical structure, electronic structure, complex dielectric function, absorption coefficient and photoconductivity of Sc or Ce doped and co-doped CrSi2, respectively. The results show that the lattice constants of CrSi2 increase with the doping of Sc and Ce, and the values of bandgap decrease with the co-doping of Sc and Ce. The band gaps of Sc, Ce and co-doped CrSi2 decrease to 0. 245 eV, 0. 232 eV and 0. 198 eV, respectively. The Fermi level of doped CrSi2 moves to the low energy region and enters the valence band. Due to the major contribution of the 3d state electrons of Sc and 4f state electrons of Ce, the single Sc or Ce doped CrSi2 appears an impurity level below the conduction band. Sc-Ce co-doping makes CrSi2 transform into metal, and the electrical conductivity is improved obviously. After doping, the first dielectric peak of the imaginary part of the CrSi2 dielectric function increases and moves towards the direction of low energy, indicating that Sc or Ce doping enhances the optical transition intensity of CrSi2 in the low energy region, and great intensity is obtained when the CrSi2 is co-doped by Sc-Ce. The absorption edge of Sc or Ce doped CrSi2 redshifts in the low energy direction. The intrinsic CrSi2 hardly absorbs photons when the photon energy is greater than 21.6 eV, especially near higher photon energies at 31. 3 eV. The absorption ability of Sc doped and Sc-Ce co-doped CrSi2 increases, and the second absorption peak is formed near E = 31. 3 eV. The results show that doping Sc or Ce can improve the absorption of CrSi2 to infrared and higher energy photons. The photoconductivity of CrSi2 increases after doping in the low energy region of less than 3.91 eV. In the energy range of 20.01 eV < E <34.21 eV, the photoconductivity of intrinsic CrSi2 is zero, but the photoconductivity of the Sc and Ce doped CrSi2 is not zero. Doping broadens the optical response range of CrSi2. The results provide a theoretical basis for the application and design of CrSi2-based optoelectronic devices. [ABSTRACT FROM AUTHOR]

Activated alkyl halides have been extensively explored to generate alkyl radicals with Ru- and Ir- photocatalysts for 1,2-difunctionalization of alkenes, but unactivated alkyl bromides remain challenging substrates due to their strong reduction potential. Here we report a three-component 1,2-difunctionalization reaction of alkenes, unactivated alkyl bromides and nucleophiles (e.g., amines and indoles) using a trinuclear gold catalyst [Au 3 (tppm) 2 ](OTf) 3 . It can achieve the 1,2-aminoalkylation and 1,2-alkylarylation readily. This protocol has a broad reaction scope and excellent functional group compatibility (>100 examples with up to 96 % yield). It also affords a robust formal [2+2+1] cyclization strategy for the concise construction of pyrrolidine skeletons under mild reaction conditions. Mechanistic studies support an inner-sphere single electron transfer pathway for the successful cleavage of inert C-Br bonds., (© 2023 Wiley-VCH Verlag GmbH.)