摘要:

The immobilization of lipophilic quaternary ammonium salts onto the large areas of the surface of silica has been accomplished. The modified silica served as a catalyst for the nucleophilic replacement of benzylic halides by cyanide.

ISSN:0022-233X    

DOI:10.1080/00222339009349699

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Low molecular weight polyethylene resulting as a by-product in a high density polyethylene plant was subjected to controlled oxidation and subsequent modification to convert the free carboxyl groups into calcium carboxylate groups. Several wax grades with useful properties and applications have thus been obtained.

ISSN:0022-233X    

DOI:10.1080/00222339009349700

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A systematic review and new approach to the syntheses of the Group VI and Group VIII transition metal derivatives of the pentaphenyl-cyclopentadienyl ligand are described. Significant enhancement in stability and reactivity of these perphenylated complexes is observed when compared to cyclopentadienyl and peralkylatedcyclopentadienyl derivatives due to their much higher molecular weights, reduced volatility, and modified solubility. These compounds have proved to be easily synthesized from the now readily available starting material, pentaphenylcyclopentadiene. Numerous physical and spectral properties as well as the x-ray crystal structure of a ruthenium derivative are reported.

ISSN:0022-233X    

DOI:10.1080/00222339009349701

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Peripherally substituted phthalocyanine (Pc) systems render more accessible the desirable properties of the Pc system, i.e., high thermal and oxidative stability as well as significant complexity ability of transition metals. After brief examination of existing synthetic methods, two new routes to substitution of the peripheral protons of the Pc system are described: (1) directed metalation of the Pc system itself followed by derivatization, and (2) directed metalation of phthalonitrile followed by derivatization and Pc formation. Each of these methods is further distinguished by providing exclusively substitution at the a-positions of the Pc nucleus. Several of the compounds have been isolated and characterized using the techniques of HPLC;1H,13C, and29Si NMR; and mass spectroscopy. These multisubstituted Pc systems are much more soluble in organic solvents than is the parent system. Such soluble macromolecules are of interest to the energy research community because of a variety of possible applications, notably the preparation of sensors, electrode coatings, catalysts, and soluble oxygen transports.

ISSN:0022-233X    

DOI:10.1080/00222339009349702

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Electrochemical polymerization of benzene has been carried out in a one-compartment cell using indium-tin oxide conducting glass as a working electrode and Pt mesh as a counterelectrode by the use of a composite electrolyte of aluminum chloride and copper(I) chloride in nitrobenzene. On applying a constant voltage at + 1.8 V vs SCE, a brown and flexible polyparaphenylene (PPP) film was smoothly obtained on the ITO anode surface. The electrical conductivity of the film as grown was 1.9 × 10−5S/cm. Aluminum and chlorine atoms were detected in the film from XPS studies, so the film might contain AlCl4−(and Cl−) as a dopant. Scanning electron micrographs of the growing side surface of the film prepared at a constant potential of + 1.8 V vs SCE showed a fibrillar morphology. The fibril diameter (∼100 nm) was similar to that of a polyaniline film. The PPP film exhibited a spin concentration of 1.0 × 1019spins/g, which corresponds to 800 phenylene units per spin. The g-value and the peak-to-peak linewidth were 2.0045 and 7 G, respectively.

ISSN:0022-233X    

DOI:10.1080/00222339009349703

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0022-233X    

DOI:10.1080/00222339009349704

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor