Pyromellitic diimidate

Polymerization by Transimidization Reaction. Exchange polymerization via equihbrium reactions is commonly practiced for the preparation of polyesters and polycarbonates. The two-step transimidization polymerization of polyimides was described in an early patent (65). The reaction of pyromellitic diimide with diamines in dipolar solvents resulted in poly(amic amide)s that were thermally converted to the polyimides. High molecular weight polyimides were obtained by employing a more reactive bisimide system (66). The intermediate poly(amic ethylcarboamide) was converted to the polyimide at 240°C. 

Pyromellitic Diimide (PMI) Naphthalene Diimidc (NDl) Perylene Diimide (PD1)... 

Figure 11.1 General structure of pyromellitic diimides, naphthalenediimide, and perylenediimide compounds (R = aryl, alkyl).

Figure 5. Electronic absorption spectrum of the product of reaction between Cr and di-n-pentyl pyromellitic diimide under argon at 180 K and after exposure to air.

Figure 6. Energy level distribution for pyromellitic diimide. The highest occupied molecular orbital is the lbjg. The chromium levels are supplied to show only how they can interact by symmetry with the orbitals on pyromellitic diimide.

Catenane 177, devoid of triple bonds, has been prepared by macrocyclization of a 1,4,5,8-naphthalenetetracar-boxylate diimide precursor bearing ethylene glycol chains and pyromellitic diimide, under standard Mitsunobu alkylation conditions, in the presence of crown ether 170 <20000L449>. 

Chang and Hung have also synthesised a PEI containing N-(carboxyphenyl) trimellitimide units linked via alkylene spacers to a pyromellitic diimide unit [83] (23). 

Mesogenic PEIs are obtained when m-aminophenol is replaced by p-ami-nophenol. A mesophase is correctly predicted in all four polymers of series 11 in Table 23. Each of the four different aromatic acids from ether diphenyl (MI score=l) to ether phenyl diphenyl (MI score=4) gives rise to a mesophase, unlike the series with pyromellitic. The Mesogenic Index approach confirms that BPTA is a much stronger mesogen than pyromellitic diimide. In fact, it predicts that if the fourth co-monomer in series 11 was an aliphatic spacer, a mesophase would still be obtained. 

TPA amide is formed by thermo-oxidation in melt and at low-temperature solid-phase oxidation. Light yellow crystals of TPA amide and TPA mixture occur and accumulate on the surface of mould samples during accelerated heat ageing at temperatures of 150-200 °C. TPA is a typical product of hydrolysis by macrochain ends. From our point of view, TPA amide product is of greater interest. Recall that analogous products (relative to polymer structure) were already observed in investigation of thermo-oxidative transformations of other APH. For example, pyromellite diimide, was identified in thermooxidation of PAI [7, 21] and classical polyimide Capton , and 2,2 -(l,4-phenylene)-bis-(phenylpyrazine), is formed by poly(phenylquinoxaline) ageing [7]. 

In this system, the fluorescence at 630 nm due to free-base 139 was at least 90% quenched, while fluorescence of 139 was not quenched in the presence of simple zinc porphyrin, suggesting that the photoinduced ET occurs from 139 to pyromellitic diimide groups in the porphyrin dimer 140. 

Starting from a 1 2 mixture of an electron-rich bis-l,5-(dinaphtho)-38-crown-10 and the electron-poor bis-acetylenic compound 1, Sanders used the template effect obtained by the inclusion of the pyromellitic diimide 1 in the crown ether to direct the oxidative coupling of the terminal alkynes toward the formation of the cyclized structure, the [2]catenane, with a 38% chemical yield. When 1 was replaced by a more electron-poor moiety obtained from 1,4,5,8-naphthalene tetracarboxylic diimide (2, Scheme 17.5) the yield of the catenane improved to 52%. 

Renault S, Geng J, Dolhem F et al (2011) Evaluation of polyketones with N-cyclic stmcture as electrode material for electrochemical energy storage case of pyromellitic diimide dilithium salt. Chem Commun 47(8) 2414-2416... 

They are formed by (a) a desymmetrized electron acceptor ring containing two different units, namely a 4,4 -bipyridinium dication (BPY " and a neutral naphthalene diimide (NDI) or pyromellitic diimide (PMI) moiety, and (b) an electron donor ring that can be symmetric for the presenee of two identical dioxybenzene (DOB) or dioxynaphthalene (DON) units, or desymmetrized by the presence of two different donors, i.e. a tetrathiafulvalene (TTF) and a DON moiety. 

N-Silylmethylphthalimide are of interest for their potential use in a variety of applications in modern organic chemistry including synthesis of N-silylmethylamines (51,53,55,57,59,60), the design of a number of unique heterocyclic structures (13—16,47,48) and new effective drugs (10—12,52,56—58,62). These compounds are promising precursors for the preparation of novel hybrid materials. Among such compounds is bis(triethoxysilyl-methyhpyromellitic diimide 50 which has been prepared by the treatment of dipotassium pyromellitic diimide with 2 M equivalents of the (chloromethyl)trietoxysilane (Scheme 24.6) (63). 

Scheme 24.6 The Reaction of Dipotassium Pyromellitic Diimide with...

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