Synthesis and characterization of polyimides containing a chiral dimine link that mimics the salen ligand

Abstract

We report the synthesis of a covalently linked complex that mimics the salen ligand within the main chain of the polyimide network. The thermally-stable solid polyimides offer suitable sites for metal coordination, which is a crucially important step in establishing steroselectivity. The ligand synthesized by the sequential treatment of a chiral trans-1,2-diaminocyclohexane and p-dimethylaminobenzaldehyde was used to prepare polyimides by a one-step polymerization in the dipolar media. A series of stable polyimides was synthesized from (1S,2S)- and (1R,2R)-bis(p-dimethylaminobenzylideneamino)-1,2-cyclohexyl and various aromatic dianhydrides had inherent viscosities ranging from 1.45 to 2.21 dl/g and were soluble in polar solvents. The glass transition temperatures were 264–319°C, and the 10% weight loss temperatures were above 406–487°C.