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The Cation Radical Chain Cycloaddition Polymerization of N ,3‐Bis( trans ‐1‐2)carbazole: The Critical Importance of Intramolecular Hole Transfer in Cation Radical Cycloaddition Polymerization
Author(s) -
Roh Yeonsuk,
Gao Daxin,
Bauld Nathan L.
Publication year - 2001
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/1615-4169(200107)343:5<481::aid-adsc481>3.0.co;2-s
Subject(s) - chemistry , cycloaddition , reactivity (psychology) , intramolecular force , polymerization , photochemistry , cobalt mediated radical polymerization , bifunctional , chain transfer , radical ion , polymer chemistry , radical polymerization , carbazole , intramolecular reaction , living free radical polymerization , cyclobutane , polymer , organic chemistry , catalysis , medicine , ion , ring (chemistry) , alternative medicine , pathology
The synthesis and polymerization of N ,3‐[bis( trans ‐1‐2)]carbazole ( 1 ) is reported. Using either the stable cation radical salt tris(4‐2)aminium hexachloroantimonate ( 2 +. ) or anodic oxidation to initiate the reaction, novel cycloaddition polymers are obtained in which the intermonomer linkages are of the cyclobutane, and to some extent of the Diels−Alder, type. A novel cation radical chain mechanism is proposed for the reaction, and extensive support for this mechanism is presented. The greatly enhanced reactivity of difunctional, as opposed to monofunctional, substrates in cation radical cycloadditions is dramatically highlighted by a comparison of the cycloaddition reactivity (rapid polymerization) of 1 versus N ‐propenylcarbazole (inefficient cyclodimerization) under electrochemical oxidation conditions. The sharply enhanced reactivity of 1 is attributed to the availability of intramolecular hole transfer in the bifunctional but not the monofunctional case.