作者:Zhen-Yu Yang
DOI:10.1016/s0022-1139(01)00462-6
日期:2001.10
Two monomers 1,2-bis(meta-aminophenyl)hexafluorocyclobutane (1), and 1,2-bis(para-aminophenyl)hexafluorocyclobutene (2), were prepared from meta- or para-nitroiodobenzenes. Palladium-catalyzed coupling reaction of trifluorovinylzine reagents with nitroiodo-benzenes gave the corresponding nitrotrifluorovinylbenzenes, which dimerized at 130-150 degreesC to give hexafluorocyclobutane derivatives. Reduction of 1,2-di(Tizeta-nitrophenyl)hexafluorocyclobutane with NaBH4 and SnCl2 afforded the diamine I in high yield. Upon treatment of 1,2-di(para-nitrophenyl)hexafluorocyclobutane with NaBH4 and SnCl2, reduction-defluorination occurred to give 2. Diamines, I or 2, polymerized with pyromellitic anhydride (A), 3,3,4,4-biphenyltetracarboxylic dianhydride (B), and 4,4'-(hexafluoroisopropylidene)-diphthalic anhydride (C), to give the corresponding poly(amic acids), which were imidized at above 250 degreesC to give thermally stable and amorphous polyimide films. (C) 2001 Elsevier Science B.V. All rights reserved.