EPR of the Co(II) complexes of phenanthraquinonedioxime and benzoquinonedioxime. Formation of dioxygen adducts in the solid state

Cobalt(II) complexes of 9, 10-phenanthrenedionedioxime (pqdH₂) and benzoquinonedioxime (bqdH₂) and the doped sample, Co(pqdH)₂/Ni(pqdH)₂ were prepared and investigated by EPR. The EPR parameters, especially the small hyperfine splitting values, reveal the presence of oxygen adduct in the concentrated (undoped) samples, while the dilute (doped) sample has parameters corresponding to a²A₁(|z²>) ground state. It is proposed that the oxygen adducts are formed as intermediates, leading ultimately to thetris-chelate Co(III) complexes of these oximes, which however could not be isolated in pure form.     

Crystal and molecular structure ofN-methylphenazinium bis(maleonitriledithiolato)gold(III), [NMP]+[Au(mnt)2]−

The crystal and molecular structure of the title compound, C₂₁H₁₁N₆S₄Au, is reported. The crystals are triclinic:P¯1,Z=2,a=7.739(1),b=8.415(1),c=17.815(1) Å,a=101.31(1),=86.20(1), =98.17(1)°. The structure was solved by the heavy-atom method, and refined by full-matrix least squares toR=0.046. Both the Au(mnt) ₂ ^– and NMP⁺ ions are planar, and form a kind of mixed stack alonga, with slightly alternating NMP⁺-Au(mnt) ₂ ^– distances of 3.46(8) and 3.59(5) Å.