Dimeric Copper(I) Complex with a Disulfonamide-Bridged Core.

Pyridine-2-yl-sulfonyl-quinolin-8-yl-amide (psq) has produced the first sulfonamidato-bridged dicopper(I) complex, {Cu[κ-(μ-κ:κ-psq)]} containing the rhombic Cu(I)N core. The single crystal X-ray structure of this complex shows that two anionic psq ligands straddle the metal atoms via bridging sulfonamide N atoms to give a Cu···Cu distance of 2.9593(8) Å. When it is dissolved in chloroform [Cu(psq)] activates C-Cl bonds as demonstrated through the rapid formation of [CuCl(psq)]. While the solid orange compound is stable for weeks under N. Acetonitrile solutions of [Cu(psq)] are rapidly oxidized in air. A 1D-carbonato-bridged coordination polymer, {Cu[κ-(μ-κ:κ-psq)][μ-CO][HO]}, and the bis-homoleptic complex [Cu(κ-psq)(κ-psq)] are concurrently isolated in high yield without evidence of ligand oxidation with HO detected as a side product. This implicit O activation was harnessed in the oxidation of phenol substrates. 2,6-Di--butylphenol is catalytically converted to the coupled dione product with 100% yield. If a para-blocked phenol is used, the reaction become stoichiometric and an O-derived hydroperoxide group is installed into the ortho position. In contrast, nitrophenol is not oxidized and the result is metal-based oxidation and isolation of [Cu(OCHNO)(psq)]. This is rationalized by this more acidic phenol acting as a proton donor, rather than a H atom donor to a putative O adduct.