Dimeric Copper(I) Complex with a Disulfonamide-Bridged Core
Mathias L Skavenborg1, Mads Sondrup Møller1, Christine J McKenzie1
1Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, 5230 Odense M, Denmark.
Abstract:
Pyridine-2-yl-sulfonyl-quinolin-8-yl-amide (psq) has produced the first sulfonamidato-bridged dicopper(I) complex, {Cu[κ4-(μ-κN:κN-psq)]}2 containing the rhombic Cu(I)2N2 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)]2 activates C-Cl bonds as demonstrated through the rapid formation of [CuCl(psq)]2. While the solid orange compound is stable for weeks under N2. Acetonitrile solutions of [Cu(psq)]2 are rapidly oxidized in air. A 1D-carbonato-bridged coordination polymer, {Cu2[κ4-(μ-κO:κN-psq)]2[μ3-CO3][H2O]}, and the bis-homoleptic complex [Cu(κ3-psq)(κ2-psq)] are concurrently isolated in high yield without evidence of ligand oxidation with H2O2 detected as a side product. This implicit O2 activation was harnessed in the oxidation of phenol substrates. 2,6-Di-tert-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 O2-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(OC6H4NO2)(psq)]2. This is rationalized by this more acidic phenol acting as a proton donor, rather than a H atom donor to a putative O2 adduct.
Related Concept Videos
03:02Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
02:42Valence Bond Theory
03:45Formation of Complex Ions
01:19Complexation Equilibria: The Chelate Effect
02:51Metal-Ligand Bonds
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
02:57Coordination Number and Geometry