Reactions of Multidentate-Ligand Copper(I) Complexes with Dioxygen

Syntheses, isolation, and characterization of several copper(I) complexes with multidentate ligands (including macrocycles), and their reactions with dioxygen are reported. A binuclear dioxygen complex was obtained from 1, 1-difluoro-4, 5, 11, 12-tetramethyl-1-bora-3, 6, 10, 13- tetraaza-2, 14-dioxo-cyclctetradeca-3, 5, 10, 12-tetraenato copper(I) in dichloromethane solution at -79° C. In the absence of excess dioxygen up to 40% of regenerated copper(I) has been observed upon warming. At room temperature the stoichiometry O2/Cu is greater than 1.0 and increases with solvent basicity. At large triphenylphosphine to copper ratios the uptake is decreased and at low ratios the uptake is enhanced. The macrocyclic complex 5, 7, 7, 12, 14, 14-hexamethyl-1, 4, 8, 11-tetra-azacyclctetradeca- 1, 4, 8, 11-tetraene copper(I) perchlorate in the solid state or in dichloromethane solution at -79° C is ketonated in either of two positions. The 3, 5, 7, 7, 10, 12, 14, 14-octamethyl derivative is ketonated in only one position. Similar reactions are observed for the 4, 11-diene copper(I) complexes as well as partial oxidative dehydrogenation.