Probing Delocalization Across Alkyne-Containing Linkages: Synthesis and Cyclic Voltammetry of Bridged Phenylenediamines.

TitleProbing Delocalization Across Alkyne-Containing Linkages: Synthesis and Cyclic Voltammetry of Bridged Phenylenediamines.
Publication TypeJournal Article
Year of Publication1995
AuthorsZhou, Q, Swager, TM
JournalJournal of Organic Chemistry
Volume60
Pagination7096–7100
ISSN0022-3263
Keywordsbridged phenylenediamine prepn cyclic voltammetry
Abstract

This paper presents the synthesis of N,N,N',N'-tetraethyl-1,4-phenylenediamines bridged by ethynyl-phenyl-ethynyl and diethynyl linkages. These compds. are of interest to det. if the N,N,N',N'-tetraethyl-1,4-phenylenediamines exhibit delocalized mixed oxidn. states when oxidized electrochem. 1-Butoxy-2,5-bis(N,N-diethylamino)-4-ethynylbenzene was a key intermediate, and nucleophilic addn. of lithium (trimethylsilyl)acetylide to 2,5-bis(N,N-diethylamino)-1,4-benzoquinone provided an efficient synthesis of this compd. This intermediate was then assembled into the redox assemblies of interest in high yield by use of palladium-catalyzed cross-coupling and copper-catalyzed oxidative homo-coupling protocols. Cyclic voltammetry of these compds. indicate that the N,N,N',N'-tetraethyl-1,4-phenylenediamine redox units behave independently and that the only interactions are electrostatic. As a result, we conclude that the electrochem. generated radical cations and dications are highly localized. [on SciFinder(R)]

DOI10.1021/jo00127a011