In the past decade, direct C-H arylation of indoles has been developed with high selectivity at the C2 and C3 positions via transition-metal-catalyzed cross-coupling reactions. Here we show that C-H activation can be directed to the C7 position with high selectivity in Pd-catalyzed coupling of indoles with arylboronic acids. The key to this high regioselectivity is the appropriate choice of a phosphinoyl directing group and a pyridine-type ligand in the presence of Pd(OAc)2 catalyst. This previously elusive transformation should provide insight for the design of other cross-couplings as well.

Modification of commercially available monophosphine ligands with either aryl bromides or chlorides by rhodium(I)-catalyzed, tertiary phosphine directed C-H activation is described. A series of ligand libraries containing mono- and diaryl-substituted groups, having different steric and electronic properties, were obtained in high yields. Based on the outstanding properties of their parent scaffolds, the modified ligands have been found to be powerful in organic reactions.

Cu2ZnSn(S1−xSex)4 nanocrystals are an emerging family of functional materials with huge potential of industrial applications, however, it is an extremely challenging task to synthesize Cu2ZnSn(S1−xSex)4 nanocrystals with both tunable energy band and phase purity. Here we show that a green and economic route could be designed for the synthesis of Cu2ZnSn(S1−xSex)4 nanocrystals with bandgap tunable in the range of 1.5–1.12 eV. Consequently, conduction band edge shifted from −3.9 eV to −4.61 eV (relative to vacuum energy) is realized. The phase purity of Cu2ZnSn(S1−xSex)4 nanocrystals is substantiated with in-depth combined optical and structural characterizations. Electrocatalytic and thermoelectric performances of Cu2ZnSn(S1−xSex)4 nanocrystals verify their superior activity to replace noble metal Pt and materials containing heavy metals. This green and economic route will promote large-scale application of Cu2ZnSn(S1−xSex)4 nanocrystals as solar cell materials, electrocatalysts, and thermoelectric materials.

Rhodium-catalyzed C7-selective decarbonylative arylation, olefination, and methylation of indoles with carboxylic acids or anhydrides by CÀHa nd CÀCb ond activation have been developed. Furthermore,C7-acylation products can also be generated selectively at alower reaction temperature in the developed system. The key to the high reactivity and regioselectivity of this transformation is the appropriate choice of an indole N-PtBu 2 chelation-assisted group.T his method has many advantages,including easy access and removal of the directing group,the use of cheap and widely available coupling agents,n or equirement of an external ligand or oxidant, ab road substrate scope,h igh efficiency,a nd the formation of asole regioisomer.

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suffer from high cost, complementary metal-oxide-semiconductor (CMOS) incompatibility, and not being environment friendly. Design and fabrication of a low-cost and CMOS-compatible siliconbased photoconductor is always urgent for current and future optoelectronics application. Unfortunately, silicon-based photoconductors usually exhibit a certain degree of latency in the photocurrent fluctuation when light is on or off, usually around 1-10 ms. [13][14][15] Meanwhile, they also suffer from a very large dark current, due to the extrinsic charge injection under reverse bias voltage, which causes the shot noise, weakens the detection sensitivity, and increases the power wastage. [12,16] Recently, the chalcogen (S, Se, and Te) and some transition metals (Au, Ti, etc.) hyperdoping in silicon has been recognized to be a potential for the fabrication of silicon-based photodetectors. [3,4,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] It has been reported that the chalcogen hyperdoped silicon photodetector can exhibit a high photoconductive gain under illumination while preserve a diode-rectifying effect in the dark. [24][25][26][29][30][31] This provides a novel path to the silicon-based photoconductors with a low noise and a high detect sensitivity. It was reported that the charge carrier trap states may play an essential role in the enhanced photoresponse. [24] However, this phenomenon has not yet been reported in the transition metal hyperdoped silicon photodetectors, and the related mechanism and its operating principle for this type of silicon photoconductors are still open for question. Meanwhile, theoretical calculations suggest that chalcogen dopant hyperdoping in silicon is not the best choice for the fabrication of photoconductors. [32,33] The silver (Ag) hyperdoping in silicon has a relatively higher optical figure of merit (v, defined by the ratio of carrier lifetime to transmit time), which is expected to have stronger potential in the optoelectronic application. [32,33] However, this interestingly theoretical prediction is still lack of the verification of related experiments.Here, we report a highly sensitive and room-temperature operated bulk silicon photodetector based on Ag hyperdoped silicon (Si:Ag). The Si:Ag samples were prepared by thermal evaporation deposition of Ag films and subsequent femtosecond pulsed laser melting (fs-PLM). A large density of Silicon-based photoconductors, with their low cost, high sensitivity, and complementary metal-oxide-semiconductor (CMOS) compatibility, have great potential for high-resolution imaging, light-activated switching, and singlephoton counting. However, they usually suffer from a large dark leakage current and a long response time, which greatly limits their applications. Here, a highperformance bulk silicon photodetector is fabricated working at room temperature with a broad spectral response range from 300 to 1200 nm through silver (Ag) hyperdoping. The detector shows a low dark current of 3.8 × 10 −7 A cm −2 and a high external quantum efficie...

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We report a regioselective direct arylation of indoles at the C7 position with (hetero)aryl bromides.