Octahedral CoII Research Articles

Identification of the cobalt(II) chloride ‘mixed’ solvate Co4Cl8(H2O)4(MeCN)6: the ionic structure trans-[Co(H2O)2(MeCN)4] trans-[Co(H2O)2(MeCN)2(CoCl4)2

The structure of the title compound features mononuclear octahedral CoII cations, trans-[Co(H2O)2(MeCN)4]2+, and trinuclear anions, trans-[Co(H2O)2(MeCN)2(CoCl4)2]2−; the latter centrosymmetric units contain a central octahedral Co(H2O)2(MeCN)2 moiety with two tetrahedral [CoCl4]2− ligands. These two large ions are held in a network of intra- and inter-molecular hydrogen bonding.

Reaction of (±)-1,1′-binaphthyl-2,2′-diyl hydrogen phosphate {(±)-phosH} with copper(II), cobalt(II) and iron(II) compounds; Identification by x-ray diffraction of [Co(CH3OH)4(H2O)2][(+)-phos][(−)-phos]. 2CH3OH·H2O

[Cu2(μO2CCH3)4(H2O)2], [CuCO3·Cu(OH)2], [CoSO4·7H2O], [Co((+)-tartrate)], and [FeSO4·7H2O] react with excess racemic (±)- 1,1′-binaphthyl-2,2′-diyl hydrogen phosphate {(±)-PhosH} to give mononuclear CuII, CoII and FeII products. The cobalt product, [Co(CH3OH)4(H2O)2]((+)-Phos)((−)-Phos) ·2CH3OH·H2O (7), has been identified by X-ray diffraction. The high-spin, octahedral CoII atom is ligated by four equatorial methanol molecules and two axial water molecules. A (+)- and a (−)-Phos− ion are associated with each molecule of the complex but are not coordinated to the metal centre. For the other CoII, CuII and FeII samples of similar formulation to (7) it is also thought that the Phos− ions are not bonded directly to the metal. When some of the CuII and CoII samples are heated under high vacuum there is evidence that the Phos− ions are coordinated directly to the metals in the products.

Thio crown ether chemistry. [Cobalt(II)·hexathio-18-crown-6], an octahedral low-spin complex of CoII

Hexathio-18-crown-6 wraps around CoII to yield a rare example of a low-spin octahedral CoII complexe, as shown by structural, magnetic, and e.s.r. studies.