Chemistry of polynuclear metal complexes with bridging carbene or carbyne ligands. Part 105. Alkylidyne tungsten and molybdenum complexes with pyrazolylmethane ligands

Abstract

The alkylidynemetal complexes [M(CR)(CO)₂{HC(pz)₃}][BF₄][HC(pz)₃= tris(pyrazol-1-yl)methane; M =W, R =Me, C₆H₄Me-4, or C₆H₃Me₂-2,6; M = Mo, R = Me or C₆H₄Me-4], [W(CMe)(CO)₂{MeC(pz)₃}][BF₄][MeC(pz)₃=1,1,1 -tris(pyrazol-1 -yl)ethane], and [W(CMe)(CO)₃{H₂C(pz)₂}][BF₄][H₂C(pz)₂= bis(pyrazol-1-yl)methane] have been prepared by treating the complexes [MBr(CR)(CO)₄] in thf (tetrahydrofuran) with TIBF₄ and HC(pz)₃, MeC(pz)₃, and H₂C(pz)₂, respectively. Reactions of the salts [W(CR)(CO)₂{HC(pz)₃}][BF₄](R = Me or C₆H₄Me-4) with the compounds [Co₂(CO)₈], [Pt(nb)₃](nb = norbornene = bicyclo[2.2.1]heptene), and [Pt(nb)(PMe₂Ph)₂] afford the mixed-metal complexes [WCo₂(µ₃-CR)(CO)₈{HC(pz)₃}][BF₄], [W₂Pt(µ-CR)₂(CO)₄{HC(pz)₃}₂][BF₄]₂, and [WPt(µ-CR)(CO)₂(PMe₂Ph)₂{HC(pz)₃}][BF₄], respectively. A trimetal complex [WPtAu(C₆F₅)(µ₃-CMe)(CO)₂(PMe₂Ph)₂{HC(pz)₃}][BF₄] has been prepared by addition of [Au(C₆F₅)(tht)](tht = tetrahydrothiophene) to [WPt(µ-CMe)(CO)₂(PMe₂Ph)₂{HC(pz)₃}][BF₄] in thf. The n.m.r. data (¹H, ¹³C-{¹H}, and ³¹P-{¹H}) for the new compounds are reported and discussed in relation to the structures proposed.