Photoinduced, copper-catalyzed reactivity of unactivated aryl and alkyl halides and photophysical characterization of a Cu(I) bis(carbazolide) complex

In a 2012 result from the Peters and Fu groups published in Science, a luminescent Cu(PPh3)2(carbazolide) complex was able to perform C-N Ullmann coupling under unusually mild conditions with a 100W-mercury lamp. This study is to date the most substantial evidence toward a single electron transfer (SET) mechanism for Ullmann coupling. Since this result, there have been several joint publications from the Peters and Fu groups entailing ligandless, photo-induced, copper-catalyzed C-N coupling of carbazoles with alkyl halides, other nitrogen nucleophiles with more diverse halide electrophiles, alkylation of amides, as well as carbon-sulfur coupling under mild conditions. This work will describe new coupling reactions which have been obsd. with use of a similar photoinduced, copper-catalyzed methodol., identifying an SET step in the mechanism. It will also report photophys. characterization and data of a copper bis(carbazolide) intermediate in C-N Ullmann coupling.