Study of the formation of polyimide from complexes of benzophenonetetracarboxylic acid diester with different diamines. 3. Dielectric study of thermal imidization

Dielectric loss peaks caused by thermal imidization were observed for the three complexes of benzophenonetetracarboxylic acid dimethyl ester (BZPE) with different diamines. The mechanism of the formation of imide rings from complexes with hydrogen bonds and with separated charges was specified. The specific features of thermal imidization of the BZPE·diaminopyridine dimeric complex were confirmed and it was shown that heat treatment of the complex of BZPE with hexamethylenediamine yields a softening polyimide and thermal imidization takes place at lower temperatures.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 534–539, March, 1990.     

Study of the formation of polyimide from complexes of benzophenonetetracarboxylic acid diester with different diamines. 2. Features of thermal imidization of the molecular complex of benzophenonetetracarboxylic acid diester with 2,6-diaminopyridine

H-bond complexes of benzophenonetetracarboxylic acid dimethyl ester with 2,6-diaminopyridine (BZPE·DAP) have a dimeric structure in which one of the amino groups of the diaminopyridine participates in the formation of an H bond and the other does not form strong intermolecular bonds. During thermal imidization, the relative reactivity of the free amino group is lower than the reactivity of the group bound in the complex. In the BZPE·DAP system, 10% of the free amino groups remain after completion of imidization and they disappear at a high temperature. It is hypothesized that they can participate in the formation of interchain imide bonds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 530–533, March, 1990.     

Investigation of the process of polyimide formation from complexes of the diester of benzophenonetetracarboxylic acid with diamines

The kinetics of thermal imidization of the H-complexes derived from the diethyl ester of 3,3,4,4-benzophenonetetracarboxylic acid (EBZP) and various diamines have been studied. A comparison of kinetic parameters obtained for the imidization of H-complexes based on ethyl or methyl esters of this acid has disclosed the differences in the behavior of each of the two H-bonds and the contribution of each bond to the mechanism of polyimide formation from the respective H-complexes.For part 5, see ref.¹ Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 300–303, February, 1993.     

Polyimides from complexes of benzophenonetetracarboxylic acid diesters with diamines. 5. Mechanism of thermal cyclization of H-complexes

The results of a study, by thermal mass spectrometric analysis and NMR spectroscopy, of the polycondensation of H-complexes are presented from which it is possible to propose a mechanism for the reaction. It is shown that conversion of the H-complexes into polyimides takes place through the formation of intermediate zwitterions with an amino acid bond after initial separation of methanol, following which elimination of water commences in one stage to form an imide ring. The role of theortho position of the functional groups in the acid ester during the formation of the hydrogen bond is discussed.Institute of Macromolecular Compounds, Russian Academy of Sciences, 199004 St. Petersburg. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2517–2524, November, 1992.     

Investigation of process of polyimide formation from complexes of diester of benzophenonetetracarboxylic acid with diamines. 1. Investigation of thermal imidization by means of IR spectroscopy

The thermal imidization of complexes of benzophenonetetracarboxylic acid diester with diamines is greatly different from the thermal imidization of the corresponding mechanical mixtures. Preliminary complexation gives a considerably greater degree of completion of the imidization. It is concluded that diffusion processes play a decisive role in the solid-phase thermal imidization of the complexes. On the basis of similar values of the free energy of activation at identical temperatures for complexes with different diamines, it is concluded that the reactivity of the functional groups has little influence on the kinetics of solid-phase imidization of the complex. Alternative schemes are proposed for the formation of polyimides from the complexes, leading to an intermediate mixed-unit prepolymer with amido acid, amido ester, and imide units in the chain.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2462–2468, November, 1989.The authors wish to thank V. V. Shamanin for discussion of the results.     

Investigation of polyimide formation from the complexes of the diester of benzophenonetetracarboxylic acid with diamines 7. Role of theo-carboxylic group of acid diester in the formation and imidization of H-complexes

The kinetics of thermal imidization of various H-complexes of semiesters of bis(o-phthalic) acids with diamines was studied. The activation energy of the imidization was shown to increase with increasing pK_a value of the diamine andE _a value of the dianhydride and with decreasing nucleophilicity of the alcohol used for the synthesis of H-complexes. The experimental kinetic data and the results of quantum chemical calculations of the heats of formation of the initial H-complexes and transition states made it possible to propose a mechanism for the imidization reaction. This mechanism takes into account the catalytic effect of the carboxylic group of the semiester in theo-position with respect to the ester group.For report 6, seeIzv. Akad. Nauk, Ser. Khim., 1993, 300 [Russ. Chem. Bull., 1993,42, 255 (Engl. Transl.)].Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1060–1065, June, 1995.     

High-pressure synthesis and properties of aliphatic–aromatic polyimides via nylon-salt-type monomers derived from aliphatic diamines and benzophenonetetracarboxylic acid

Aliphatic polyimides (P-XBTA) having inherent viscosities of 0.4–1.4 dL/g were readily synthesized by the high-pressure polycondensation of the salt monomers, composed of aliphatic diamines having various methylene chain lengths (X = 4–12) and 3,3′,4,4′-benzophenonetetracarboxylic acid (BTA), under 200–250 MPa at 200–320°C. The salt monomers with odd-numbered methylene units were found to be more susceptible to crosslinking than those containing even-numbered methylene chains. The polyimides having even-numbered methylene units were highly crystalline, whereas those with odd-numbered methylene chains were crosslinked and therefore amorphous with only one exception, i.e., P-11BTA. The thermal behavior of these polymers was also studied. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 39–47, 1998     

Macrocyclic divalent transition metal complexes of acetylacetone buckled with two different diamines

Metal-mediated condensation of o-phenylenediamine with bisacetylacetone-ethylenediimine yields 14-membered tetraaza macrocyclic six-coordinate complexes of the type [M(mac)Cl₂],[M(mac)SO₄·H₂O] (where M = Fe^II, Co^II and Cu^II; MAC = macrocyclic ligand formed in the template reaction). The metal ions are coordinated by four azomethine nitrogen atoms bridged by acetylacetone moieties. The electrical conductance magnetic moments, electronic and IR spectral data of all complexes are discussed.     

Structure-property study of polyimides derived from PMDA and BPDA dianhydrides with structurally different diamines

A series of aromatic diamines were polymerized with two aromatic dianhydrides, pyromellitic dianhydride and 3,3^′,4,4^′-biphenyltetracarboxylic dianhydride, and the resulting poly(amic acid)s were thermally cyclodehydrated to aromatic polyimides. The polyimides were characterized by determining the glass transition temperatures (T_g), thermal stability, coefficients of thermal expansion, and wide-angle X-ray diffraction. Structure-property relationships are elucidated and discussed in terms of the structural fragments in the polymer chain. The PMDA-based polyimides generally revealed a higher T_g than the corresponding BPDA-based analogues. Generally, the dilution of the imide content by the insertion of oxyphenylene segments into the diamines significantly reduced the T_g. The introduction of m- or o-phenylene units into the polymer backbone usually resulted in a decrease in T_g. The attachment of pendant groups on the backbone may lead to decreased or increased T_gs, depending on the structure of pendant groups. As evidenced by X-ray diffraction, the polyimides derived from rigid, rod-like diamines or the diamines having two or three p-oxyphenylene showed a higher crystalline tendency. The presence of aliphatic pendant groups slightly reduced the thermal stability of the polyimides. The other structural changes did not show a dramatic influence on the thermal stability. Some polyimides obtained from p- or m-phenylenediamine had low thermal expansion coefficients below 2×10−5°C⁻¹.     

Study of the structure of solutions of the H-complexes of diesters of tetracarboxylic acids with diamines by the light scattering method 1. H-complex of the dimethyl ester of benzophenonetetracarboxylic acid with hexamethylenediamine

Conclusions about structure formation in solutions of the H-complexes of benzo-phenonetetracarboxylic acid with hexamethylenediamine have been drawn from the angular dependence of the intensity of scattered polarized light. The calculated statistical structural parameters show that the H-complexes form dipentameric associations. At high concentrations of the complexes in aqueous-methanolic solution the supermolecular structure is disrupted, while in the pure alcohol the reverse process is observed.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1338–1343, June, 1991.     

Formation of uranium mixed oxides from thermal decomposition of uranyl propionate complexes

Four new derivatives of uranium with propionic acid, ammonium and various divalent cations have been synthesized, whose general formula corresponds to NH₄M[UO₂(C₂H₅COO)₃]₃nH₂O, (M=Mn⁺⁺, Co⁺⁺, Ni⁺⁺ and Zn⁺⁺). These compounds have been studied by X-ray diffraction, differential thermal and thermogravimetric analysis, so as to identify the different solid phases isolated during heat treatment. The existence of a new double oxide of uranium and cobalt with fluorite type structure has also been shown.

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Zusammenfassung Vier neue Derivate des Urans mit Propionsäure, Ammonium und verschiedenen zweiwertigen Kationen wurden synthetisiert. Die allgemeine Formel ist: NH₄M[UO₂(C₂H₅COO)₃]₃nH₂O, (M=Mn⁺⁺, Co⁺⁺, Ni⁺⁺ und Zn⁺⁺). Diese Verbindungen wurden durch Röntgendiffraktion, Differentialthermoanalyse und thermogravimetrische Analyse untersucht um die während der Wärmebehandlung isolierten verschiedenen Festphasen zu identifizieren. Die Existenz eines neuen Doppeloxides von Uran und Cobalt mit einer Struktur von Fluorit-Typ wurde ebenfalls nachgewiesen.

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Résumé Quatre nouveaux dérivés de l'uranium avec l'acide propionique, l'ammonium et divers cations bivalents ont été synthétisés. Leur formule générale correspond à NH₄M[UO₂(C₂H₅COO)₃]₃ nH₂O, (M=Mn⁺⁺, Co⁺⁺, Ni⁺⁺ et Zn⁺⁺). Ces composés ont été examinés par diffraction des rayons X ainsi que par analyses thermique et thermogravimétrique afin d'identifier les différentes phases solides isolées pendant leur traitement thermique. L'existence d'un nouvel oxyde double d'uranium et de cobalt de structure type fluorine est également démontrée.

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, NH₄M[UO₂(C₂H₅COO)₃]₃ · n₂, M=Mn⁺⁺, Co⁺⁺, Ni⁺⁺ Zn⁺⁺. - , , , . .

     

Synthesis of diester disulfimides derived from 4- and 5-methoxycarbonyl-2-sulfobenzoic acid imides

Ester interchange of 4-and 5-methoxycarbonyl-2-sulfobenzoic acid imides with glycols was studied.     

Synthesis of bicyclic N,N-enaminals by cyclization of alk-4-ynals with aliphatic diamines in DMSO upon treatment with KOH

A cyclization of alk-4-ynals with aliphatic diamines in DMSO upon treatment with KOH was found to lead to bicyclic N,N-enaminals. The studies of this reaction showed that 1,3-diaminopropane and N-methyl-1,3-diaminopropane gave (E)-6-(arylmethylidene)octahydropyrrolo[1,2-a]pyrimidines in 45—78% yields, whereas 1,2-diaminoethane gave 5-(arylmethylidene)hexahydropyrrolo[1,2-a]imidazoles as mixtures of E- and Z-isomers in up to 75% total yield. The mechanism of these new cascade cyclization reactions includes formation of the equilibrium mixtures of imines and cyclic aminals with subsequent intramolecular hydroamination of the triple bond having considerable ionic character.     

Syntheses and thermal properties of some complexes with 2-mercaptonicotinic acid

The biological activity of a kind of hetero-bimetallic Schiff-base complex was studied using Escherichia coli (E. coli) cell as the target. By microcalorimetry, the difference of anti-bacterial activity between the binuclear Schiff-base and the ligand was determined and analyzed. To analyze the inhibition of the bacterial growth internally, the E. coli cells grown in the presence of hetero-bimetallic Schiff-base complex were observed by scanning electron microscopy. The images in high resolution revealed the damage of outer cell membrane caused the inhibitory effect on E. coli. Inductively coupled plasma-mass spectrometry results proved the absorption of the complex by cells, which confirmed the interaction between the Schiff-base and biological macromolecule.     

Spectral and thermal studies of divalent transition metal complexes with indole-2-carboxylic acid and 4-substituted hydrazinethiocarbamide

Ternary complexes of Co(II), Ni(II) and Cu(II) with indole-2-carboxylic acid (A) and 4-substituted hydrazinethiocarbamide (L) [4-phenylhydrazinethiocarbamide (L1), 4-benzylhydrazinethiocarbamide (L2) and 4-(2-propenyl)hydrazinethiocarbamide (L3)] were prepared. The structures of the complexes were proposed by molar conductance, electronic, IR, 1H NMR, mass spectra as well as thermogravimetric (TG) studies. An octahedral structure is suggested for Co(II), Ni(II) and Cu(II) ternary complexes.