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Tin‐based halide perovskite materials have been successfully employed in lead‐free perovskite solar cells, but the overall power conversion efficiencies (PCEs) have been limited by the high carrier concentration from the facile oxidation of Sn2+ to Sn4+. Now a chemical route is developed for fabrication of high‐quality methylammonium tin iodide perovskite (MASnI3) films: hydrazinium tin iodide (HASnI3) perovskite film is first solution‐deposited using presursors hydrazinium iodide (HAI) and tin iodide (SnI2), and then transformed into MASnI3 via a cation displacement approach. With the two‐step process, a dense and uniform MASnI3 film is obtained with large grain sizes and high crystallization. Detrimental oxidation is suppressed by the hydrazine released from the film during the transformation. With the MASnI3 as light harvester, mesoporous perovskite solar cells were prepared, and a maximum power conversion efficiency (PCE) of 7.13 % is delivered with good reproducibility. [ABSTRACT FROM AUTHOR]

Tin‐based halide perovskite materials have been successfully employed in lead‐free perovskite solar cells, but the overall power conversion efficiencies (PCEs) have been limited by the high carrier concentration from the facile oxidation of Sn2+ to Sn4+. Now a chemical route is developed for fabrication of high‐quality methylammonium tin iodide perovskite (MASnI3) films: hydrazinium tin iodide (HASnI3) perovskite film is first solution‐deposited using presursors hydrazinium iodide (HAI) and tin iodide (SnI2), and then transformed into MASnI3 via a cation displacement approach. With the two‐step process, a dense and uniform MASnI3 film is obtained with large grain sizes and high crystallization. Detrimental oxidation is suppressed by the hydrazine released from the film during the transformation. With the MASnI3 as light harvester, mesoporous perovskite solar cells were prepared, and a maximum power conversion efficiency (PCE) of 7.13 % is delivered with good reproducibility. [ABSTRACT FROM AUTHOR]

A DFT comparative mechanistic study unveils that the TBD-catalyzed reactions of amines with CO2 and hydrosilanes may either undergo a neutral mechanism or a mechanism involving free ions, depending on the polarity of the solvent. The nucleophilicity of the amines is an important factor to determine the chemoselectivities of the reactions to give formamide or aminal/N-methylated amine. [ABSTRACT FROM AUTHOR]

Presented herein is an intriguing effect of fluorine, and it allows difluoroenol silyl ethers to couple with aryliodanes in a redox‐neutral manner to afford ortho‐iodo difluoroalkylated arenes. The remaining iodide group provides a versatile platform for converting the products into various valuable difluoroalkylated arenes. The reaction shows excellent functional‐group compatibility and broad substrate scope. A DFT mechanistic study suggests that the fluorine effect facilitates a subtle nucleophilic attack of the oxygen atom of enol silyl ethers onto aryliodanes, therefore leading to a rearrangement. Taking effect: An intriguing effect of fluorine in difluoroenol silyl ether distinguishes it from other enol silyl ethers by enabling its cross‐coupling with aryliodanes. This reaction represents the first cross‐coupling of enol silyl ethers by rearrangement, and involves concomitant reduction of iodine(III) to iodine(I). Tf=trifluoromethylsilyl, TMS=trimethylsilyl. [ABSTRACT FROM AUTHOR]

Presented herein is an intriguing effect of fluorine, and it allows difluoroenol silyl ethers to couple with aryliodanes in a redox‐neutral manner to afford ortho‐iodo difluoroalkylated arenes. The remaining iodide group provides a versatile platform for converting the products into various valuable difluoroalkylated arenes. The reaction shows excellent functional‐group compatibility and broad substrate scope. A DFT mechanistic study suggests that the fluorine effect facilitates a subtle nucleophilic attack of the oxygen atom of enol silyl ethers onto aryliodanes, therefore leading to a rearrangement. [ABSTRACT FROM AUTHOR]

Abstract: We herein report a robust catalyst‐free cross‐coupling between ArI(OAc)2 and α‐stannyl nitriles, aided by TMSOTf. The transformation introduces a cyanoalkyl group to the ortho position of ArI(OAc)2 and simultaneously reduces the aryl iodine(III) to iodide, thus providing α‐(2‐iodoaryl) nitrile as the product. This transformation could be completed within 5 min at −78 °C and features superb functional‐group tolerance and efficient scalability. DFT calculations indicate that the formation of a ketenimine(aryl)iodonium intermediate and subsequent [3,3]‐sigmatropic rearrangement are involved as key steps. [ABSTRACT FROM AUTHOR]

Abstract: We herein report a robust catalyst‐free cross‐coupling between ArI(OAc)2 and α‐stannyl nitriles, aided by TMSOTf. The transformation introduces a cyanoalkyl group to the ortho position of ArI(OAc)2 and simultaneously reduces the aryl iodine(III) to iodide, thus providing α‐(2‐iodoaryl) nitrile as the product. This transformation could be completed within 5 min at −78 °C and features superb functional‐group tolerance and efficient scalability. DFT calculations indicate that the formation of a ketenimine(aryl)iodonium intermediate and subsequent [3,3]‐sigmatropic rearrangement are involved as key steps. [ABSTRACT FROM AUTHOR]