摘要:

AbstractPolymeric cobalt dinitrogen complexes were synthesized by two different methods: by the ligand substitution reaction of polymers5a–cand6a–c, containing 4‐diphenylphosphinophenylethylene units (3) or 4‐diphenylphosphinomethylphenylethylene units (4), respectively, with hydridodinitrogentris(triphenylphosphine)cobalt(I) (CoH(N2)(PPh3)3), or by the direct reaction of tris(acetylacetonato)cobalt(III) with triphenylphosphine, the polymers5a–cor6a–c, and triisobutylaluminium under nitrogen. The intensity of thev N 2band in the IR spectrum of the polymeric dinitrogen complex was found to be about four times as that of CoH(N2)(PPh3)3. Ammonia was formed after hydrolysis of the complex, which was prepared by mixing a tetrahydrofuran solution of naphthaline, lithium, and titanium tetrachloride with the polymeric dinitrogen complex. The yields of ammonia in the case of the polymeric complexes were high in comparison with that obtained with CoH(N2)(PPh3)3. The highest yields of ammonia were obtained when a mole ratio [P̄]/[Co]<1 ([P̄] is the concentration of phosphino groups in the polymer and [Co]is that of Co in CoH(N2)(PPh3)3), a temperature of −20°C, and a reaction time

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820201

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractRadical copolymerizations of (−)‐3‐menthyl maleate (1) were carried out with styrene, with indene, and with isobutyl vinyl ether. The copolymers were hydrolyzed with potassium hydroxide. After hydrolysis the copolymers were still optically active, due to an introduction of asymmetry into the main chain of the copolymer. The mechanism of asymmetric induction and the position of the new asymmetric center are discussed based on measurements of UV spectra, optical rotation, optical rotatory dispersion, and circular dich

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820202

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractInvertase, glucose oxidase, α‐chymotrypsin, urease, and β‐galactosidase were immobilized on polymers2aor2b(in bead or gel form), usingp‐benzoquinone or cyanogen bromide as activating reagents. The resulting insoluble derivatives were found to have high total enzymatic activities (76–83% in the case of invertase) retaining 62 to 84% of their initial activity after storing for 3 to 8 weeks. On the other hand, a column of β‐galactosidase immobilized on Trisacryl‐H was used for 120 h continuous product

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820203

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

Abstract5‐Phenyl‐1,3‐dioxolan‐2,4‐dione (the anhydrocarboxylate derivative of mandelic acid) has been shown to undergo polymerisation in the presence of tertiary organic bases such as pyridine in a reaction that has somewhat unusual characteristics. Thus, although the reaction in nitrobenzene shows first‐order kinetic dependence on both monomer and pyridine over a reasonable concentration range, the pyridine is not consumed and does not appear to control the molecular weight of the resultant polymer. The most important factor in controlling molecular weight is the presence of adventitious moisture which enters into the polymerisation process producing poly‐α‐esters that are hydroxyl/carboxyl terminated. The rate of polymerisation increases progressively as pyridine is replaced by 2‐methylpyridine and 2,6‐dimethylpyridine but decreases dramatically when 2‐methoxypyridine is used, indicating the importance of the basicity of the attacking species. The results are interpreted in terms of the interaction of the basic nitrogen and the C‐4 ring carbonyl leading to the formation of a transient charge transfer complex which subsequently decomposes to form pyridine, carbon dioxide and the α‐lactone. The chain growth process involves the interaction of the α‐lactone with any nucleophiles present which control the molecular weigh

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820204

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

Abstractα‐Ethyl‐α‐phenyl‐β‐propiolactone (7) of an optical purity up to 95% was prepared; the resolution of the two optical antipodes was carried out with the optical active precursor ethyl 2‐aminomethyl‐2‐phenylbutyrate (5), and the optical purity was determined by1H NMR analysis using europium salt shift reagents. The solution and thermal properties of the corresponding polyesters8, as obtained by anionic ring opening polymerization, were investigated. It was found that the inherent viscosity increased with the optical purity of the lactone. Distinct differences in the melting behaviour were found between the racemic and the optically active polymers; the ideal melting temperatureTM0for the pure enantiomeric polymer was estima

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820205

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractN‐(4‐aminobenzenesulfonyl)‐N′‐butylurea (8) (glibutamide®) and several amino compounds were grafted on water soluble and non‐toxic polymeric backbones, with the intention to study the influence of such a carrier on the hypoglycemic effects of the drug, covalently linked by ester and (or) amide bonds. The spacer by which the drug was fixed to the polymeric carrier contained 1 to 10 atoms. So far, the hypoglycemic effect of only one polymer (13d) was tested. It showed, however, negative results probably due to the amide bond of the drug which is difficult

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820206

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractAnion exchange equilibria were studied by the batch technique on macroporous polystyrene resins with the following functional groups:\documentclass{article}\pagestyle{empty}\begin{document}$ - \mathop {\rm N}\limits^ + {\rm H}_{\rm 2} {\rm CH}_{\rm 3} ({\rm M),} - \mathop {\rm N}\limits^ + {\rm H(CH}_{\rm 3} )_2 ({\rm DE),} - \mathop {\rm N}\limits^ + {\rm (CH}_{\rm 3} )_3 ({\rm TM),} - \mathop {\rm N}\limits^ + {\rm H}_{\rm 2} {\rm CH}_{\rm 2} {\rm CH}_{\rm 2} {\rm OH (E),} - \mathop {\rm N}\limits^ + {\rm H}_{\rm 2} {\rm (CH}_{\rm 2} {\rm CH}_{\rm 2} {\rm OH)}_{\rm 2} ({\rm DE),} - \mathop {\rm N}\limits^ + {\rm (CH}_{\rm 2} {\rm CH}_{\rm 2} {\rm OH)}_{\rm 3} ({\rm TE),} - \mathop {\rm N}\limits^ + {\rm CH}_{\rm 3} {\rm (CH}_{\rm 2} {\rm CH}_{\rm 2} {\rm OH)}_{\rm 2} ({\rm MDE), and} - \mathop {\rm N}\limits^ + {\rm (CH}_{\rm 3} {\rm )}_{\rm 2} {\rm CH}_{\rm 2} {\rm CH}_{\rm 2} {\rm OH (DME)}$\end{document}. The selectivity order for these groups in slightly acidic, dilute solutions for the following anion systems: Br−/Cl−, I−/Cl−, and ClO4−/Cl−was found to be TM>DME>MDE>TE>DM>M>DE>E, but it was entirely reversed in the case of F−/Cl−system. These results are discussed in view of some known theories of ion exchange selectivity. It seems that the experimental data can be best explained in terms of the Chu‐Diamond‐Whitney theory which takes into consideration mainly changes of the water structure caused by counter‐ions, co‐ions, and functional grou

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820207

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractThe complexation reaction of poly(L‐glutamic acid) (1), with Cu ions in aqueous solution was studied by pH titration, spectroscopy, circular dichroism measurements and solution viscosity. The adsorption of Cu ions depended on the secondary structure of1; 1adsorbed Cu ions when its degree of neutralization was higher than 0,6. Thus, this phenomenon was attributed to the helix‐coil transition of1. It was cleared that the helical structure was retained because of chelating between Cu ions and carboxyl groups of the side chain of1. The formation of the Cu/1complex was compared with that of the Cu/poly(acrylic acid) complex

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820208

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractThe structure of the Cu/poly(L‐glutamic acid), (Cu/1), complex was studied by magnetic susceptibility, circular dichroism, electron spin resonance, and light scattering measurements. Cu/1(pH 5,5) formed a binuclear complex by stabilizing the helix structure using [1]/[Cu]= 10. When the amount of Cu ions became small, the structure of the Cu/1complex changed from a binuclear complex to a mononuclear one. Furthermore, it was obvious that an intermolecular bridged complex of Cu/1was formed at pH = 5,5, because the molecular weight of the Cu/1complex was about 13 fold that of1, when the mixing mole ratio [1]/[Cu]was 1

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820209

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractThe kinetics of quaternization of poly(acrylonitrile‐co‐2‐methyl‐5‐vinylpyridine) (1) by methyl iodide was investigated. The rate constantkwas shown to be independent of the degree of quaternization τ and the second order is valid for the reaction, independent of τ. From the dependence ofkon the temperature, the thermodynamic parameters of the reaction were deduced and compared with literature data. Under the conditions to obtain τ = 1 inN‐methylpyrrolidone as solvent, a low charge polyelectrolyte was produced, soluble in DMF without decrease of the average molecular weight. The viscosimetric behaviour of the copolymer in DMF as solvent (in presence or absence of external KI salt) was studied, dependent on the charge density controlled by τ, and the ageing depends on the presence of oxygen, on the basicity of the solvent, on the degree of quaternization, and on the nature and concentration of the external salt. A mechanism is proposed, which implies the oxidation of the I−counterions to IO3−, initiating an intramolecular cyclisation of

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820210

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY