CRYSTAL-STRUCTURE AND MOLECULAR-CONFIGURATION OF A TETRANUCLEAR COPPER(II) COMPLEX ACTIVE AS A CATALYST IN THE OXIDATIVE COUPLING OF PHENOLS BY DIOXYGEN - CU4OCL6(NMP)3(OH2=NMP) (NMP=N-METHYL-2-PYRROLIDINONE)

The species Cu4OCl6(nmp)3(OH2 &.nmp), an active catalyst for the oxidative coupling of phenols by dioxygen, has been studied by means of a single-crystal X-ray structural analysis. The complex crystallizes in the centrosymmetric monoclinic space group with [FORMULA OMMITED] Diffraction data were collected on a Syntex P21 diffractometer using graphite-monochromatized Mo Kα radiation. The structure was solved via direct methods (using multan) and refined via least-squares methods to RF=5.65% and RWF=4.69% for those 3203 independent reflections with 4.5<2θ<40.0°. The complex has a central μ4-oxide ion [0(50)] surrounded tetrahedrally by four copper atoms [FORMULA OMMITED] the six chloride ligands are each in a μ2-bridging mode and bridge each of the Cu.Cu vectors. The Cu4OCl6 core of the molecule has approximate Td symmetry. Three of the copper atoms are linked to nmp ligands [FORMULA OMMITED] while the fourth copper atom is linked to an aquo ligand [Cu(l)-OH2=1.936 (6) Å], The aquo ligand is additionally involved in hydrogen bonding to an otherwise free nmp molecule in the crystal lattice. © 1979, American Chemical Society. All rights reserved.