摘要:

AbstractSome new polymers and model compounds were obtained from the reaction of 2‐phthalimidosuccinic anhydride (5) or 2,2′‐pyromellitdiimidodisuccinic anhydride (10). The way of the ring‐opening reaction of the anhydrides was found to depend on the solvents used. In some polar solvents such as DMSO, DMAC, NMP and DMF, β‐orientation occurs, but in THF, 1,4‐dioxane or acetone α‐orientation is preferred, which can be followed quantitatively by NMR spectroscopy. Subsequent dehydration to the pyrrolobenzimidazoles was found to proceed via the corresponding benzimidazolylcarboxylic acids rather than via the cyclic imides, the formation of the β‐from being faster than that of the α‐form. Polymer24, containing pyromellitdiimide and pyrrolobenzimidazole moieties in the main chain, was synthesized by a three‐step reaction starting with10and 3,3′‐diaminobenzidine (8). In the first step, the poly(aminoanilic acid) (12), containing pyromellitdiimide rings, was prepared in a polar solvent. In the second step, condensation to the corresponding poly(imidoimidazolylpropionic acid) (20) was carried out thermally in solution or in solid state at 80–160°C. In the final step, the conversion into polymer24was performed by heating at a higher temperature or at reflux in acetic anhydride. The structures of the polymers were identified spectroscopically by comparison of the IR and NMR spectra with those of the

ISSN:0025-116X    

DOI:10.1002/macp.1986.021871101

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractA novel addition polymerization of 1,4‐diethynylbenzene (1) with 1,4‐benzenedithiol (2) was studied under UV‐irradiation in toluene solution at −20°C. The addition polymerization was found to proceed rapidly and a pale‐yellowish polymer precipitated with the progress of the reaction (M̄n= 7500). A soluble polymer was recovered from the toluene solution by evaporation. ItsM̄nvalue was estimated to be 3000. When an excess amount of2was used (mole ratio1:2= 2:3), the yield of the insoluble polymer increased. TG of the polymer indicated its decomposition point to be ≈500°C in air. The electroconductivity of the insoluble and soluble polymers was found to be 10−2S · cm−1and 10−5S · cm−1when doped with I2at room temperature, respectively, and the conductivity was reversibly increased with increasing temperature up to 90°C. AtT>90°C the iodine was released and

ISSN:0025-116X    

DOI:10.1002/macp.1986.021871102

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractCopolymers containing covalently bound phthalocyanine moieties (4) or tetraphenylporphyrine moieties (5) were prepared by the reaction of partially chloromethylated polystyrene (3) with the low molecular substituted phthalocyanine1band tetraphenylporphyrine2b, respectively. Combined binding of moieties of1band2byielded polymer6. The photoredox behavior of1, 2, 4, 5and6was investigated under irradiation with visible light in the presence of a donor and an acceptor. Mixtures of sensitizers (1 + 2and4 + 5) resulted in reduced photocatalytic properties. Only in the case of6, due to reduced intermolecular interactions, higher yields of photochemical reaction products were obtained.

ISSN:0025-116X    

DOI:10.1002/macp.1986.021871103

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractN‐carboxyanhydride of 4‐amino‐4‐carboxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl (5), a new paramagnetic monomer, was synthesized, starting from 2,2,6,6‐tetramethyl‐4‐oxo‐piperidine (1), which was oxidized to 2,2,6,6‐tetramethyl‐4‐oxo‐piperidine‐1‐oxyl (2). Applying the Bucherer‐Bergs synthesis, 4‐amino‐4‐carboxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl (4) was obtained. The key step in the synthesis of5is the reaction of the derived amino acids4aand4cwith phosgene. From the two procedures which were considered the reaction of4cwith phosgene affords theN‐carbox

ISSN:0025-116X    

DOI:10.1002/macp.1986.021871104

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractCyclohexano anellated crown ethers, bis(phenylcyclohexano)‐18‐crown‐6 and benzo‐cyclohexano‐18‐crown‐6 withcis‐ andtrans‐ configuration at the cyclohexane ring were synthesized. The phenyl substituted crown ethers react with formaldehyde to form a crosslinked resin. Depending on the reaction conditions, the benzo anellated crown ethers give soluble polymers and/or linear and cyclic oligomers. Cyclic products could be isolated. Crosslinked polymers were synthesized from benzo‐cyclohexano‐18‐crown‐6 using additionally to formaldehyde a dialde

ISSN:0025-116X    

DOI:10.1002/macp.1986.021871105

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe binding of hemoglobin with high molecular weight dextran sulfate and diethylaminoethyl (DEAE) dextran was studied by turbidimetry, viscosimetry, ultrafiltration and oxygen affinity measurements. The results indicate that a complex is formed between hemoglobin and the charged dextrans through salt bridges. This complexation can lead to precipitation if the ionization degree of hemoglobin is high enough to develop an extensive neutralization of the charges of polyionic dextrans. At the pH value near to the isoelectric point, complexation still occurs, probably through salt bridges between the polyelectrolytes and the ionized sites of opposite charge on the hemoglobin molecule, but the complexes remain soluble in solution. Binding appears to be stronger for the hemoglobin‐dextran sulfate compounds than for the hemoglobin‐DEAE dextran compounds. The oxygen affinity of hemoglobin is greatly decreased in the presence of dextran sulfate, indicating a stabilization of the deoxyhemoglobin with respect to the oxyhemoglo

ISSN:0025-116X    

DOI:10.1002/macp.1986.021871106

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe anionic ring‐opening polymerization of 2,2‐dimethyltrimethylene carbonate in solution withsec‐butyllithium as initiator was found to result under suitable conditions in a bimodal molecular weight distribution, vic. cyclic oligomers and a high‐molecular‐weight polymer. The concentration of cyclic oligomers approaches that of a ring chain equilibrium. In the kinetically controlled regime high polymer yields were obtained. Optimum reaction conditions for a polymer yield of 85 – 95% are a temperature of −10°C, an initial monomer concentration of 10 weight‐% and toluene as solvent. In THF the ring chain equilibrium is achieved readily. The ceiling temperature was determined to be ≈ 30°C. The homopolymer was characterized by spectroscopic, thermoanalytical and viscosity measurements. A high degree of crystal

ISSN:0025-116X    

DOI:10.1002/macp.1986.021871107

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThis work deals with the modification reaction of amylose with diketene using tertiary amines as catalysts. The structure of the resulting polymers was determined by means of IR,1H and13C NMR spectroscopy as well as by chemical analysis. A linear dependence of the reaction rate on polymer, diketene and pyridine concentrations was found. The activation energy was found to be 27,2 kJ/mol (6,5 kcal/mol). Polymeric chelates between partially modified amylose and cupric ions (Cu2+) were prepared. However, not all of the β‐keto ester groups in the partially modified amylose participate in binding the cupric io

ISSN:0025-116X    

DOI:10.1002/macp.1986.021871108

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe free radical polymerization of styrene initiated by 1,1,2,2‐tetraphenyl‐1,2‐diphenoxyethane (TPPA) can be described as a kind of dead end polymerization. At the beginning of the polymerization, mainly oligomers are formed by primary radical chain termination. These oligomers can be characterized by thin layer and gel permeation chromatography and by mass spectroscopy. With increasing conversion and decreasing initiator concentration the molecular weight of the polymers is increasing. Contrary to the polymerization of methyl methacrylate with the same initiator, in the case of styrene the formed oligomers are not able to initiate once more the polymerization because the end groups formed by initiator radicals and styrene units are rather stable at normal polymerization temperatures (60 –

ISSN:0025-116X    

DOI:10.1002/macp.1986.021871109

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractSelective sulfation of the primary hydroxyl group of chitosan was performed by means of the pyridine‐SO3complex after the positions 2 and 3 of the aminoglucopyranosidic ring were protected by coordination with copper ions. The requirements for complexing copper ions were investigated as a function of the pH and Cu(II)/chitosan mole ratio of the starting solution. Cu(II)‐chitosan complexes were characterized by ESR and13C NMR CP‐MAS investigations; two different paramagnetic Cu(II) species were observed, whose relative quantity changes by changing the pH of the starting solution. Thegtensor values (species I:g1‖= 2,28,g1‖= 2,06,A2‖= 160 G; species II;g2‖= 2,24,g2‖= 2,06,A2‖= 160 G) are consistent with a CuN2O2chromophore. The sulfation reaction was studied in the range of 25 to 75°C using 2 : 1 to 6 : 1 pyridine‐SO3/Cu(II)‐chitosan mole ratios. Under optimized reaction conditions, a selective 6‐Osulfation was obtaine

ISSN:0025-116X    

DOI:10.1002/macp.1986.021871110

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY