Intrinsically Microporous Polyimides Based on a Rigid-Soft Structure for Hydrogen Separation.

Polyimide (PI)-based gas separation membranes are of great interest in the field of H purification owing to their good thermal stability, chemical stability, and mechanical properties. Among polyimide-based membranes, intrinsically microporous polyimides are easily soluble in common organic solvents, showing great potential for fabricating hollow fiber gas separation membranes. However, based on the solution-diffusion model, improving the free volume or the movability of polymer chains can improve gas permeability, but would result in poor thermal stability.

Multicomponent Dearomative Difluoroalkylation of Isoquinolines with Difluorinated Silyl Enol Ethers: Divergent Synthesis of -Difluorinated Heterocycles.

A multicomponent dearomative difluoroalkylation of isoquinolines has been developed with difluorinated silyl enol ethers serving as poor nucleophiles without an additional transition-metal or organic catalyst. The sequential oxidative rearomatization under different alkaline conditions provides a controllable formal C-H difluoroalkylation and difluoromethylation method for isoquinolines without peroxide or metal oxidant. A series of isoquinolines including a pharmaceutical, phenanthridine, quinolines, and difluorinated silyl enol ethers were suitable substrates to construct -difluorinated heterocycles.