A novel synthetic route to rigid‐rod polyimides

Abstract

A new synthetic approach to soluble, rigid-rod, aromatic polyimides is described. The polycondensation is done by a Pd-catalyzed aryl-aryl coupling of N,N-bis(4-bromo-2,5-didodecylphenyl)-l,2 : 4,5-pyromellitic diimide (2) and 2,5-didodecyl-l,4-benzenediboronic acid (3). Here, the imide structure is already preformed in monomer 2. A structurally identical polymer is synthesized by the classical procedure condensing 1,2 : 4,5-pyromellitic dianhydride (PMDA) (4) and 4,4"-diamino-2,5,2',5',2",5"-hexadode~l-~-terphenyl(5). Both polymers are characterized in detail by 'H and I3C NMR spectroscopy, membrane osmometry and size exclusion chromatography. The average degree of polycondensation is of the order of 15. The thermal behaviour of the polymers is studied by differential scanning calorimetry and thermogravimetrical analysis.

The tenth anniversary of Suzuki polycondensation (SPC)

“…43,44 A long-standing problem of surface sciences, the interaction of organic compounds with metal surfaces, was addressed with polymers 12 and 13. 35 As observed earlier for rigid-rod poly(imide)s with terphenylene units (polymer 70 46,47 ), these polymers adsorb onto gold surfaces in ultrathin layers (15-25 Å) from solution. On copper, the thickness of these layers depends on the presence or absence of oxidizing agents.…”

“…The corresponding 2,5-dibromopyrrole derivative together with 2,5-didodecylbenzene bisboronic acid furnishes polymer 68, 84 whose thermal treatment gives the polyarylene copolymer 69 with one or three pyrrolic units per repeat unit, which is otherwise not accessible. Polymer 70 46,47 is a novel rigid-rod type polyimide; polymer 71 85 can be used for retro Diels-Alder chemistry to access, for example, unusual poly(arylene ethinylene)s; and the reduction of polymer 72 86 yields the radical anion 73, which was investigated as a model for onedimensional polaronic ferromagnetism.…”

The tenth anniversary of Suzuki polycondensation (SPC)

“…A long‐standing problem of surface sciences, the interaction of organic compounds with metal surfaces, was addressed with polymers 12 and 13 35. As observed earlier for rigid‐rod poly(imide)s with terphenylene units (polymer 70 46, 47), these polymers adsorb onto gold surfaces in ultrathin layers (15–25 Å) from solution. On copper, the thickness of these layers depends on the presence or absence of oxidizing agents.…”

“…The corresponding 2,5‐dibromopyrrole derivative together with 2,5‐didodecylbenzene bisboronic acid furnishes polymer 68 ,84 whose thermal treatment gives the polyarylene copolymer 69 with one or three pyrrolic units per repeat unit, which is otherwise not accessible. Polymer 70 46, 47 is a novel rigid‐rod type polyimide; polymer 71 85 can be used for retro Diels–Alder chemistry to access, for example, unusual poly(arylene ethinylene)s; and the reduction of polymer 72 86 yields the radical anion 73 , which was investigated as a model for one‐dimensional polaronic ferromagnetism.…”

Synthesis and characterization of polyimides from imidazole-blocked 2,5-bis[(n-alkyloxy)methyl]-1,4-benzene diisocyanates and pyromellitic dianhydride

“…Up to now have been reported three pyromellitic polyimides with different side-chain structures: nalkyloxy (-OC,H,,+,; n = 4-16),13 methoxypolyethyleneoxy [ -O(CH2CHzO)y-CH3; y = 2, 3]14 and n-alkyl n = 12). 15 The first and second polyimides were prepared by condensation of pyromellitic dianhydride [PMDA] with the nalkyloxy-and methyloxypoly(ethy1eneoxy)-disubstituted, imidazole-blocked diisocyanates, respectively, and the last one by Pd-catalyzed condensation of pyromellitimidecontaining benzene dibromides with didodecyl-substituted benzene diboronic acids. The n-alkyloxy groups-pendant polypyromellitimides were found to be highly ~rystalline'~ due to well-ordered side chains, but the methyloxypoly(ethy1eneoxy) groups-substituted ones showed low ~rystallinity'~ due to lateral disorder of the side chains.…”