Mechanistic Insights into Solvent and Ligand Dependency in Cu(I)-Catalyzed Allylic Alkylation with <i>gem</i>-Diborylalkanes

The recent Cu-catalyzed allylic substitution reaction between <i>gem</i>-diboryalkane and allyl electrophiles shows intriguing solvent and ligand-controlled regioselectivity. The α-alkylation product was obtained in DMF solvent, while γ-alkylation product was obtained in dioxane solvent and the dioxane and NHC ligand situation. In the present study, density functional theory calculations have been used to investigate the reaction mechanism and origin of the regioselectivity. For both dioxane and DMF, γ-alkylation undergoes successive oxidative addition (CH₂Bpin trans to leaving group) and direct Cγ–C reductive elimination. The α-alkylation is found to undergo oxidative addition (CH₂Bpin trans to leaving group), isomerization, and Cα–C reductive elimination rather than the previously proposed oxidative addition (−CH₂Bpin cis to the leaving group) and Cα–C reductive elimination. The γ-alkylation and α-alkylation is, respectively, favorable for dioxane and DMF solvent, which is consistent with the γ- and α-selectivity in experiment. The solvent interferes the isomerization step, thereby affects the relative facility of the α- and γ-alkylation. Further investigation shows that η¹-intermediate formation promoted by solvent is the rate-determining step of the isomerization. The stronger electron-donating ability of DMF than dioxane facilitates the η¹-intermediate formation and finally results in the easier isomerization in DMF. For dioxane and NHC situation, in the presence of neutral NHC ligand, the −PO₄Et₂ group tightly coordinates with the Cu center after the oxidative addition, preventing the isomerization process. The regioselectivity is determined by the relative facility of the oxidative addition step. Therefore, the favorable oxidative addition (in which −CH₂Bpin trans to the leaving group) results in the facility of γ-alkylation

Additional file 1 of Multidisciplinary-derived clinical score for accurate prediction of long-term mortality in fibrotic lung disease patients

Additional file 1. Table S1. The AUC and cutoff for different predictors. DLCO (% predicted) was the most accurate variable for predicting outcomes, with an Area Under the Curve (AUC) of 0.88, followed by mMRC Dyspnea Score (AUC = 0.82), 6MWT distance (AUC = 0.80), and GAP score (AUC = 0.77). The respective cutoffs for these variables were 63% for DLCO, 1 for mMRC Dyspnea Score, 392 meters for 6MWT distance, and 2 for GAP score

Ultrafast, Self-Driven, and Air-Stable Photodetectors Based on Multilayer PtSe₂/Perovskite Heterojunctions

We report on the large-scale synthesis of polycrystalline multilayer PtSe₂ film with typical semimetallic characteristics. With the availability of the large-area film, we constructed a heterojunction composed of multilayer PtSe₂ and Cs-doped FAPbI₃, which can function as a self-driven photodetector in a broadband wavelength from the ultraviolet to the near-infrared region. Further photoresponse analysis revealed that the heterojunction device showed outstanding photosensitive characteristics with a large <i>I</i>_light/<i>I</i>_dark ratio of 5.7 × 10³, high responsivity of 117.7 mA W^–1, and decent specific detectivity of 2.91 × 10¹² Jones at zero bias. More importantly, the rise/fall times were estimated to be 78/60 ns, rendering our device the fastest device among perovskite-2D photodetectors reported to date. In addition, it was also observed that the PtSe₂/perovskite photodetector can almost retain its photoresponse properties after storage in ambient conditions for 3 weeks. This study suggests the potential of the present PtSe₂/perovskite heterojunction for future air-stable ultrafast photodetecting applications