Branched polyphenylenes by repetitive Diels-Alder cycloaddition

被引:59
作者
Shifrina, ZB
Averina, MS
Rusanov, AL
Wagner, M
Müllen, K [1 ]
机构
[1] Max Planck Inst Polymerforsch, Mainz, Germany
[2] Russian Acad Sci, Nesmeyanov Inst Organoelement Cpds, Moscow, Russia
关键词
D O I
10.1021/ma991369f
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
Diels-Alder reactions between 1,4-bis(2,4,5-triphenylcyclopentadienone-3-yl)benzene and either phenylacetylene (model reaction) or 1,4-diethynylbenzene (polymer formation) were studied. NMR spectra suggest that the main product in the model reaction is the m,m-isomer (up to 83% yield). X-ray crystal structure analysis convincingly proved the structure of the above isomer. The polymer-forming reaction was carried out using different concentrations of the monomeric building block and different reaction times. As a result, branched polyphenylenes with M(w) in the range of 1.2 x 10(4)-12 x 10(4) g mol(-1) were obtained. Both the model compound and the polymers were subjected to intramolecular oxidative cyclodehydrogenation with copper(II) trifluoromethanesulfonate and aluminum chloride. According to LD-TOF mass spectrometry, the cyclodehydrogenation of the model compound afforded the planarized polycyclic aromatic hydrocarbon C(66)H(26) This polycyclic aromatic compound was isolated in 91% yield. The extended rr-conjugation and ordering of cyclodehydrogenated products were demonstrated by Raman spectroscopy.
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页码:3525 / 3529
页数:5
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