Complexes of copper(I) with aromatic compounds facilitate selective electrophilic aromatic substitution
The copper(I)-aromatic ring complex is formed in situ from Cu(II) and metallic copper in deaerated aqueous solutions containing the aromatic compounds. Phenol or toluene shift the comproportionation reaction of copper(0) and copper(II) towards the formation of Cu(I):
The stability constant of Cu(I)-phenol in aqueous solutions was reported previously as 900 ± 100 M−1. The surprisingly stable dπ* Cu(I)-phenol complex causes distortion of the ring structure which facilitates selective substitutions. Similar results are reported for sulfonation of phenol (in aqueous solutions) and for nitration and sulfonation of toluene in a two phase process.
Document Type: Research Article
Affiliations: 1: Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel; 2: Chemical Engineering Department, Sami Shamoon College of Engineering of the Negev, Israel; 3: Chemistry Department, Ben Gurion University of the Negev, Israel
Publication date: July 3, 2018