Oxidative ligand cleavage in a copper(II) complex containing aniline moiety induced by copper(II) perchlorate in acetonitrile

Abstract

Synthetic reaction of a Cu(II) complex containing aniline moiety (Cu(atpa)) (atpa = N‐(anthracen‐9‐ylmethyl)‐2‐((bis(pyridin‐2‐ylmethyl)amino) with an excess Cu(ClO4)2 in CH3CN produced an unusual species, which was not corresponding to the original ligand atpa, Cu(ClO4)2 nor [Cu(atpa)]2+. It was proposed that the new species was generated via electron transfer between aniline‐containing N‐based ligand and Cu(ClO4)2, resulting in oxidative ligand cleavage. Monitoring the reaction of Cu(atpa) with Cu(ClO4)2 for a period of time revealed a gradual decrease of an active species, concomitant with the growth of a variety of organic fractions including 9‐anthraldehyde and anthraquinone compounds. Cu(tpa) (Cu coordinated with tripodal amine ligand without anthracene analogue) was also detected from this reaction. This finding was indicative of an oxidative ligand cleavage via the N‐dealkylation pathway. In addition to oxidative ligand cleavage, the new species was competent to oxidize other substrates such as triphenylphosphine (PPh3) as well.