Synthesis and Structural Features of Co(II) and Co(III) Complexes Supported by Aminotrisphenolate Ligand Scaffolds

Co­(II) complexes of aminotrisphenolate ((ArO)₃N^3–) ligands can be prepared straightforwardly in high yield. X-ray analysis reveals these complexes to comprise of two different hemispheres, one containing an anionic Co­((ArO)₃N)⁻ and the other a cationic (ArO)₃NH⁺ unit, which are associated through hydrogen bonding. These Co­(II) complexes can be easily converted into their Co­(III) analogues in air in the presence of suitable bases such as dimethylaminopyridine and 2,2′-bipyridine, and the structural features and magnetic properties of these latter compounds are also reported

Oxidant-Free Au(I)-Catalyzed Halide Exchange and C_sp2–O Bond Forming Reactions

Au has been demonstrated to mediate a number of organic transformations through the utilization of its π Lewis acid character, Au­(I)/Au­(III) redox properties or a combination of both. As a result of the high oxidation potential of the Au­(I)/Au­(III) couple, redox catalysis involving Au typically requires the use of a strong external oxidant. This study demonstrates unusual external oxidant-free Au­(I)-catalyzed halide exchange (including fluorination) and C_sp2–O bond formation reactions utilizing a model aryl halide macrocyclic substrate. Additionally, the halide exchange and C_sp2–O coupling reactivity could also be extrapolated to substrates bearing a single chelating group, providing further insight into the reaction mechanism. This work provides the first examples of external oxidant-free Au­(I)-catalyzed carbon–heteroatom cross-coupling reactions