LEWIS BASICITY OF THE [CO4O4](4+) CUBANE CORE - PREPARATION OF A MIXED-VALENCE (4CO(II),4CO(III)) CLUSTER WITH AN UNUSUAL [CO-8(MU(4)-O)(4)](2+) CORE, AND NEW [CO4O3(OH)](5+) AND [CO4O2(OH)(2)](6+) CUBANE COMPLEXES

[Co8O4(O(2)CPh)(12)(MeCN)(3)(H2O)] 1b is formed on oxidation of cobalt(II) benzoate in MeCN or dmf with aqueous H2O2, and contains a [Co4O4](4+) cubane unit with each oxide attached to an additional Co atom; studies stimulated by this result show that preformed [Co4O4(O(2)CR)(2)(bipy)(4)](2+) (bipy = 2,2'-bipyridine) can be mono- and doubly-protonated to [Co4O3(OH)(O(2)CR)(2)(bipy)(4)](3+) and [Co4O2(OH)(2)(O(2)CR)(2)(bipy)(4)](4+), respectively.