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  • 1
    Electronic Resource
    Electronic Resource
    Liquid crystalline side-chain polysiloxanes containing mesogenic groups attached by esterification (1991)
    Springer
    Polymer bulletin 27 (1991), S. 37-40 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Liquid crystalline side-chain polysiloxanes were prepared without metal complex catalyst. Mesogenic groups such as cholesteryl, 4-cyano-4′-biphenyl and 4-methoxy-4′-biphenyl group were introduced into polysiloxane by esterification and from DSC measurements they were compatible with other liquid crystalline polysiloxanes reported previously.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296322
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  • 2
    Electronic Resource
    Electronic Resource
    Esterolyses of p-nitrophenyl esters catalyzed by dialkylaminopyridines attached to polyorganosiloxane (1992)
    Springer
    Polymer bulletin 27 (1992), S. 413-420 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The present study describes the preparation of polyorganosiloxanes containing dialkylaminopyridines in their side chains (POS-DAAPs) and the use of them as catalysts for esterolyses of p-nitrophenyl esters of CH3(CH2) n COOH (n=0–5). The POS-DAAPs (4, 5) were prepared from poly[(3-chlorocarbonylpropyl)methylsiloxane] (PCCPMS, 1) and two pyridine derivatives, such as 4-[(2-hydroxyethyl)methylamino]pyridine (HEMAP, 2) and 4-[4-(2-hydroxyethyl)piperidino]pyridine (HEPP, 3). Pyridyl groups of POS-DAAPs 4 and 5 were partially quaternized with dimethylsulfate (6, 7) in order to carry out esterolysis in homogenious systems. The esterolyses were examined in methanol/tris(hydroxymethyl)-aminomethane-hydrochloric acid buffer solution (vol. ratio 2/1, pH of buffer solution: 7.5) and analyzed following Michaelis-Menten like kinetics. The second-order rate constants (k 2/K m) of the esterolyses catalyzed by POSs 6 and 7 were 22–38 fold values of those catalyzed by the corresponding monomolecular catalysts 2 and 3. In addition, the effects of POSs were discussed from the kinetic, thermodynamic, and activation parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00309698
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  • 3
    Electronic Resource
    Electronic Resource
    Oxidation of 3-methylindole catalyzed by cobalt(II)phthalocyanines covalently bound to polyorganosiloxane (1991)
    Springer
    Journal of inorganic and organometallic polymers and materials 1 (1991), S. 211-221 
    Details
    ISSN: 1572-8870
    Keywords: Polyorganosiloxane ; cobalt(II)phthalocyanine ; polymeric catalyst ; oxidation ; 3-methylindole ; polymer conformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two kinds of cobalt(II)phthalocyanines covalently bound to polyorganosiloxane (POS) were prepared to be applied as catalysts for the oxidation of 3-methylindole in organic solvents. The catalytic activity of the POS whose carboxyl residues were methyl-esterified was high compared with that of the POS which has carboxyl residues. The former polymeric atalyst exhibited higher catalytic activity than monomolecular phthalocyanine, indicating an appearance of effects of polymer chains. The factors which influence the catalytic oxidation, e.g., polymer conformations, basicity of solvents, and equilibrium involving phthalocyanine monomer and the dimer, are discussed. It has become apparent that polymer conformation influences catalytic activity and that the catalytic activity of the POS, whose main chains are mobile, is high.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00701320
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis of polyorganosiloxanes with imidazolyl groups in the side chain (1990)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 191 (1990), S. 497-503 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An imidazolyl ring was introduced into the side chain of poly(3-chlorocarbonylpropylmethyl-siloxane) (4) by esterification with 4(5)-hydroxymethylimidazole (1), the imino group being protected during esterification by the 2-nitrobenzyl group which can be easily cleaved by UV light irradiation without attacking the main chain. The photolytic cleavage of the 2-nitrobenzyl group was completed with a yield of ≈ 100% after 2 h without any remarkable side reaction. The polyorganosiloxanes (6), with a high content of imidazolyl groups in the side chain, are slightly soluble in hot DMSO and DMF. From this fact, in addition to the result of the measurement of Tg, it is suggested that very strong intermolecular hydrogen bonds are operating.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1990.021910305
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesis of polysiloxanes with pendant viologen groups and their characteristic behavior of aggregation and deposition observed on electron transfer (1990)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 191 (1990), S. 2871-2880 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In order to prepare polysiloxanes with the ability of electron transport, pendant viologen groups were introduced. Chloromethylated poly(methyl-β-phenethylsiloxane) (2) was reacted with monoalkylbipyridinium chlorides (3a, 3b) to give polysiloxanes (4a, 4b) containing pendant viologen groups. These polymers show reversible redox behavior. They are deposited on ITO electrodes when the pendant viologen dication groups are electrochemically reduced to cation radicals. The polymer deposited shows an absorption maximum (λmax) at 500 nm, which is due to a highly aggregated structure of cation radicals. On the contrary, when the electrode was coated by the polymer before the measurement (pre-cast membrane), the cation radicals formed electrochemically show λmax at 530 nm, indicating that the degree of aggregation is lower than that in the membrane formed reductively from solution.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1990.021911203
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  • 6
    Electronic Resource
    Electronic Resource
    Influence of various apolar groups in polycationic polyorganosiloxanes upon polyion complexation with poly(methacrylic acid) (1986)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 187 (1986), S. 1159-1167 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyion complexes are formed from poly(methacrylic acid) and polycationic polyorganosiloxanes modified with various apolar groups in the main chain or in the side chains. Potentiometric titration measurements with solutions of the complexes indicate that the chemical structure of the composed polycation influences complexation in aqueous solution. From a binding study with methyl orange, it is seen that the electrostatic interaction of the polyion complexes is enhanced by an increase of the hydrophobicity in the composed polycations. In water/ethanol solutions, however, such a tendency is not observed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1986.021870513
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of phthalocyaninatocobalt (II) covalently bound to polyorganosiloxane (1989)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 2303-2309 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyorganosiloxane containing phthalocyaninatocobalt(II) in the side chain (PCPMSTACo(II)Pc) (4) was synthesized from poly[(3-carboxypropyl)methylsiloxane] (PCPMS) (1) and 2,9,16,23-tetraaminophthalocyaninatocobalt(II) (TACo(II)Pc) (3). The wavelength of maximum absorption of TACo(II)Pc in PCPMS-TACo(II)Pc in solution of N,N-dimethylformamide (DMF) is shifted depending on the polymer environment. From UV/VIS spectra of PCPMS-TACo(II)Pc, most of the phthalocyanine moieties in PCPMS-TACo(II)Pc may be expected to exist monomeric in methanol as well as in DMF. The glass transition temperature (Tg) of PCPMS-TACo(II)Pc is high compared with that of PCPMS and the maximum Tg is 50°C. Further, the formation of a crosslinked film is reported, and in this film most of the phthalocyanine moieties may be expected to exist dimeric as concluded from the UV/VIS spectrum. This dimer formation and intramolecular bridges between TACo(II)Pc and carboxyl groups are considered to influence Tg, because they reduce the mobility of the main chains.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1989.021900931
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  • 8
    Electronic Resource
    Electronic Resource
    Hydroquinone oxidation catalyzed by pyridine-Cu(II) complexes attached to polyorganosiloxanes (1992)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 193 (1992), S. 59-67 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Cu(II) complexes of polyorganosiloxanes with pyridyl group in the side chains (1-6) were investigated as catalysts for hydroquinone oxidation. The catalytic oxidations followed Michaelis-Menten-like kinetics. The kinetic parameters were evaluated, and the greatest value of k2/Km is 119 dm3 · mol-1 · s-1 due to the large value of k2 (0,262 s-1) in methanol/water (vol. ratio 2/1) at 25°C. It has been shown that the main factors which influence the substrate-binding process are hydrophobicity, hydrogen bonding between functional groups in the side chains, conjugation and basicity of pyridine, and adsorption of substrate by amido groups. Large k2 values were obtained in the present system due to flexibility and hydrophobicity of the siloxane backbone. Additionally, in the activation process, hydrogen bonding between amido groups, which is easily formed due to the flexibility of the polymer chains, should contribute to decrease both activation enthalpy and activation entropy.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1992.021930106
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  • 9
    Electronic Resource
    Electronic Resource
    Concentration quenching of photoluminescent Ru(bpy)2+3 dispersed in a polysiloxane film containing 2,2′-bipyridine pendant groups in dependence of molecular distribution (1995)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 196 (1995), S. 1241-1250 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The photoluminescent Ru(bpy)2+3 complex was dispersed in a polysiloxane film containing 2,2′-bipyridine (bpy) pendant groups. The unusually long photoluminescence lifetime of the Ru(bpy)2+3 (1,94 μs at 25°C) and the blue-shifted photoluminescent wavelength suggest a rigid polymer matrix. The fluorescence yield becomes lower with higher probe concentration, indicating concentration quenching. According to the analysis based on Stern-Volmer plots, the quenching obeys a mechanism composed of both static and dynamic processes. A statistical intermolecular distance distribution between the probes was used to interpret the results in terms of static and dynamic quenching. It is shown that in the present system the dispersed complexes diffuse slightly during the excited state.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1995.021960423
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