Polyimides with carbonyl and ether connecting groups between the
申请人:The United States of America as represented by the Administrator of the
公开号:US05145937A1
公开(公告)日:1992-09-08
New polyimides have been prepared from the reaction of aromatic dianhydrides with novel aromatic diamines containing carbonyl and ether connecting groups between the aromatic rings. Several of these polyimides were shown to be semi-crystalline as evidenced by wide angle x-ray diffraction and differential scanning calorimetry. Most of the polyimides form tough solvent resistant films with high tensile properties. Several of these materials can be thermally processed to form solvent and base resistant moldings.
Ni-catalyzed decarboxylative C(sp3)−N cross-coupling of redox active ester and oxime esters was realized through electrochemical cathodic reduction. Mechanistic studies unveil a high-valent nickel species-driven reductive elimination pathway, rather than direct radical-radical coupling. The utility of this methodology was demonstrated through a broad scope (1°, 2°, 3° carboxylic acids) and late-stage