Since it has been known that cyanide ions co-ordinate to Cu2þ
ions to form a very stable complex Cu(CN)x,61 the selectivity study
of 1eCu2þ complex to CN using copperecyanide affinity was paid to our special attention. Besides, the weak bonding property of 1eCu2þ complex may contribute to forming more stable Cu(CN)x by
addition of CN.