The syntheses and X-ray crystal structures of novel transition metal cluster arrays containing 2–5 coordinated [(CO)9Co3(μ3-CCOO)]− ligands in a variety of geometries

Reaction of (CO)9Co3(μ3-CCOOH) with metal trifluoroacetates leads to the isolation of Cr2{μ-OOC-CCo3(CO)9}2{μ-OOCCF3}2(THF)2, 1, and Sm2{μ-OOCCCo3(CO)9}2{μ-OOCCF3}4{(CO)9Co3CCOOH}2(THF)2·2THF, 2, which are cluster substituted analogs of known organic carboxylates. Reaction of Pt(II) acetate, prepared in situ, with (CO)9Co3(μ3-CCOOH) leads to PtCo{μ-OOCCCo3(CO)9}3(μ-OOCCH3){(CO)9Co3CCOOH}, 3, which contains an unusual Pt(II)Co(II) dimeric core. Reaction of Zn(OH)2 with (CO)9Co3(μ3-CCOOH) in THF leads to Zn4(μ4-O){μ-OOC-CCo3(CO)9}6 but in 2-MeTHF the reaction leads to ZnCo{μ-OOCCCo3(CO)9}3{Co(CO)4}{2-(CH3)C4H7O}, 4. This compound features the presence of a [Co(CO)4]− moiety coordinated to a Co(II) center. Reaction of Cr(II) acetate with (CO)9Co3(μ3-CCOOH) in noncoordinating solvents results in CoCr2(μ3-O){μ-OOCCCo3(CO)9}4(μ-OOCCH3)2{(CO)9Co3CCOOH}2(H2O)·C7H8, 5a, and Cr3(μ3-O){μ-OOCCCo3(CO)9}4(μ-OOCCH3)2{(CO)9Co3CCOOH}(CH3OOH)2·C7H8, 5b, which are cluster ligand analogs of known organic carboxylate oxo metal trimers. Finally, deprotonation of (CO)9Co3(μ3-CCOOH) with a bulky base inhibits the base degradation of the tricobalt cluster sufficiently such that [C10H6(N(CH3)2)2H][Co2{μ-OOCCCo3(CO)9}3{OOCCCo3(CO)9}2], 6, can be isolated. All compounds are structurally characterized by X-ray crystallography and selected spectroscopic techniques.