Novel soluble and optically active polyimides containing axially asymmetric 9,9′-spirobifluorene units: Synthesis, thermal, optical and chiral properties

Synthesis, Chiral Resolution, and Absolute Configuration of C2‐Symmetric, Chiral 9,9′‐Spirobifluorenes

“…In 1988, Toda published a procedure for the resolution of 2,2′‐dihydroxy‐9,9′‐spirobifluorene through clathrate formation with ( R , R )‐(+)‐2,3‐dimethoxy‐ N , N , N′ , N′ ‐tetracyclohexylsuccindiamide,11 which was refined and improved by Thiemann in 2005 12. Although this approach has been applied successfully by us5e,5h and others6e,6h,13 it is quite tedious. This is not only due to the fact that the tartaric acid derivative must be synthesised in three steps and tends to racemise during the second step.…”

“…In this study Chiralpak AD‐H was employed as chiral stationary phase for the preparative resolution of 3,3′‐ and 4,4′‐dihydroxy‐9,9′‐spirobifluorene 16. Nevertheless, in the case of chiral 9,9′‐spirobifluorenes, HPLC has primarily been used for analytical purposes 6h,13. The reason for this is most likely the nature of the stationary phase Chiralpak AD‐H, which has been used in all resolutions of chiral 9,9′‐spirobifluorenes so far.…”

Synthesis and characterization of heat-resistant and soluble poly(amide-imide)s from unsymmetrical dicarboxylic acid containing 2-(triphenyl phosphoranylidene) moiety and various aromatic diamines

“…[1][2][3][4][5][6] However, some applications of polyimides are limited due to their poor solubility in common organic solvents, high glass transition temperature and high processing temperature, which are due to molecular stiffness and high level intermolecular packing of this polymeric system. In order to overcome these limitations, various synthetic efforts have been exercised in order to improve processability of polyimides without sacrificing the above mentioned excellent properties.…”

Synthesis and properties of novel soluble and high T g poly(ether imide)s from diamine containing 4,5-diazafluorene and trifluoromethyl units

“…Terraza et al prepared fluorene‐bridged polyimides with high refractive indices and small birefringence; Zhu et al synthesized fluorenyl cardo polyimides with improved solubility in organic solvents. Diamine and dianhydride containing spiro(fluorene‐9,9′‐xanthene) units, spirobifluorene groups and fluorene units have been designed for the syntheses of their respective polyimides. The 4,5‐diazafluorene units differ from the parent fluorene by the replacement of the CH groups in the latter with N atoms.…”