The syntheses and X-ray crystal structures of novel transition metal cluster arrays containing 2–5 coordinated [(CO) 9Co 3(μ 3-CCOO)] − ligands in a variety of geometries

Abstract

Reaction of (CO) 9Co 3(μ 3-CCOOH) with metal trifluoroacetates leads to the isolation of Cr 2{μ-OOC-CCo 3(CO) 9} 2{μ-OOCCF 3} 2(THF) 2, 1, and Sm 2{μ-OOCCCo 3(CO) 9} 2{μ-OOCCF 3} 4{(CO) 9Co 3CCOOH} 2(THF) 2·2THF, 2, which are cluster substituted analogs of known organic carboxylates. Reaction of Pt(II) acetate, prepared in situ, with (CO) 9Co 3(μ 3-CCOOH) leads to PtCo{μ-OOCCCo 3(CO) 9} 3(μ-OOCCH 3){(CO) 9Co 3CCOOH}, 3, which contains an unusual Pt(II)Co(II) dimeric core. Reaction of Zn(OH) 2 with (CO) 9Co 3(μ 3-CCOOH) in THF leads to Zn 4(μ 4-O){μ-OOC-CCo 3(CO) 9} 6 but in 2-MeTHF the reaction leads to ZnCo{μ-OOCCCo 3(CO) 9} 3{Co(CO) 4}{2-(CH 3)C 4H 7O}, 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) 9Co 3(μ 3-CCOOH) in noncoordinating solvents results in CoCr 2(μ 3-O){μ-OOCCCo 3(CO) 9} 4(μ-OOCCH 3) 2{(CO) 9Co 3CCOOH} 2(H 2O)·C 7H 8, 5a, and Cr 3(μ 3-O){μ-OOCCCo 3(CO) 9} 4(μ-OOCCH 3) 2{(CO) 9Co 3CCOOH}(CH 3OOH) 2·C 7H 8, 5b, which are cluster ligand analogs of known organic carboxylate oxo metal trimers. Finally, deprotonation of (CO) 9Co 3(μ 3-CCOOH) with a bulky base inhibits the base degradation of the tricobalt cluster sufficiently such that [C 10H 6(N(CH 3) 2) 2H][Co 2{μ-OOCCCo 3(CO) 9} 3{OOCCCo 3(CO) 9} 2], 6, can be isolated. All compounds are structurally characterized by X-ray crystallography and selected spectroscopic techniques.