Syntheses and Characterization of Two Dioxygen-Reactive Dinuclear Macrocyclic Schiff-Base Copper(I) Complexes

The dinuclear copper(«) complex [Cu2U(CH3CN)2](C104)2 (1, L = 3,6,9,17,20,23-hexaazatricyclo[23.3.1.1]triaconta1(29),2,9,11(30),12(13),14,16,23,25,27-decaene) has been structurally characterized. As previously described, intramolecular ligand hydroxylation (at the aromatic ring) was observed when 1 was reacted with dioxygen. A stopped-flow analysis of the reaction of 1 with dioxygen under different conditions did not allow a "dioxygen intermediate" to be spectroscopically detected. Detailed NMR and electrochemical data on 1 are also presented and evaluated for the first time. No copper(ll) complexes of U could be characterized due to hydrolysis of the compounds. In contrast, complex 2—differing from 1 only in an increase in the size of the chelate rings—did not undergo intramolecular hydroxylation when it was oxidized. The crystal structure of 2 is also described.