Palladium-Catalyzed Synthesis of Pure, Regiodefined Polymeric Triarylamines
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- 作者：Felix E. Goodson ; Sheila I. Hauck ; and John F. Hartwig
- 刊名：Journal of the American Chemical Society
- 出版年：1999
- 出版时间：August 25, 1999
- 年：1999
- 卷：121
- 期：33
- 页码：7527 - 7539
- 全文大小：518K
- 年卷期：v.121,no.33(August 25, 1999)
- ISSN：1520-5126
文摘
Triarylamine polymers were prepared by palladium-catalyzed amination of aryl halides, and theelectrochemical and magnetic properties of these materials were studied. Through a careful evaluation of thecatalytic and polymer chemistry involved in this process, triarylamine polymers that are exclusively linear andfree of phosphorus impurity in the polymer chain have been prepared. To suppress molecular weight-limitingside reactions from palladium-catalyzed poly(N-arylaniline) polymerizations, a number of phosphines werescreened in reactions of small molecules to form triarylamines. Of these phosphines, tris(o-methoxymethylphenyl)phosphine (7) and tri(tert-butyl)phosphine (8) led to quantitative amination without ligand arylation,aryl bromide hydrodehalogenation, or exchange of phosphine aryl groups with the aryl bromide. When thesephosphines were used in polymerizations, significant improvements in molecular weights were observed, butan additional molecular weight limiting side reaction, the formation of cyclic oligomers, was not affected.Strategies to minimize cyclizations that compete with chain growth were explored, including the use ofoligomeric monomers that greatly reduced the formation of cyclic oligomers. A chromatographic methodcompletely removed low molecular weight cyclic oligomers. A number of poly(N-arylaniline) derivatives withMw values as high as 105 g/mol were synthesized by using the optimized palladium-catalyzed method, and theelectronic and magnetic properties of these materials were investigated by cyclic voltammetry, magneticsusceptibility, and EPR spectroscopy.