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

Abstract

Reaction of (CO)(9)Co-3(mu(3)-CCOOH) with metal trifluoroacetates leads to the isolation of Cr-2{mu-OOC-CCo3(CO)(9)}(2){mu-OOCCF3}(2)(THF)(2), 1, and Sm-2{mu-OOCCCo3(CO)(9)}(2){mu-OOCCF3}(4){(CO)(9)Co3CCOOH}(2)(THF)(2). 2THF, 2, which are cluster substituted analogs of known organic carboxylates. Reaction of Pt(II) acetate, prepared in situ, with (CO)(9)Co-3(mu(3)-CCOOH) leads to PtCo{mu-OOCCCo3(CO)(9)}(3)(mu-OOCCH3){(CO)(9)Co3CCOOH}, 3, which contains an unusual Pt(II)Co(II) dimeric core. Reaction of Zn(OH)(2) with (CO)(9)Co-3(mu(3)-CCOOH) in THF leads to Zn-4(mu(4)-O){mu-OOC-CCo3(CO)(9)}(6) but in 2-MeTHF the reaction leads to ZnCo{mu-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)(9)Co-3(mu(3)-CCOOH) in noncoordinating solvents results in CoCr2(mu(3)-O){mu-OOCCCo3(CO)(9)}(4)(mu-OOCCH3)(2){(CO)(9)Co3CCOOH}(2)H2O). C7H8, 5a, and Cr-3(mu(3)-O){mu-OOCCCo3(CO)(9)}(4)(mu-OOCCH3)(2){(CO)(9)Co3CCOOH}(CH3OOH)(2). C7H8, 5b, which are cluster ligand analogs of known organic carboxylate oxo metal trimers. Finally, deprotonation of (CO)(9)Co-3(mu(3)-CCOOH) with a bulky base inhibits the base degradation of the tricobalt cluster sufficiently such that [C10H6(N(CH3)(2))(2)H][Co-2{mu-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.