Chemistry of vinylidene complexes XI. Synthesis of trinuclear MnFePt complexes by means of consecutive assembling out of mono- and dimetal vinylidene precursors

Abstract

The dimetal μ-vinylidene complexes Cp(CO) 2MnPt( μ-C = CHPh)L 2 (L = tert.-phosphine or -phosphite), which have been obtained by coupling of the mononuclear complex Cp(CO) 2Mn=C=CHPh and unsaturated PtL 2 unit, add smoothly the Fe(CO) 4 moiety to produce trimetal MnFePt compounds. The μ 3-vinylidene cluster CpMnFePt( μ 3-C=CHPh)(CO) 6(PPh 3) was prepared in quantitative yields from the reactions of Cp(CO) 2MnPt( μ-C=CHPh)(PPh 3)L (L = PPh 3 or CO) with Fe 2(CO) 9 in benzene at 20 °C. The phosphite-substituted complexes Cp(CO) 2Mnpt( μ-C=CHPh)L 2 (L = P(OEt) 3 or P(OPr i) 3) react under analogous conditions with Fe 2(CO) 9 to give mixtures (2:3) of the penta- and hexacarbonyl clusters, CpMnFePt( μ 3-C = CHPh)(CO) 5L 2 and CpMnFePt( μ 3-C = CHPh)(CO) 6L, respectively. The similar reaction of the dimetal complex Cp(CO) 2MnPt( μ-C = CHPh)(dppm), in which the Pt atom is chelated by dppm = Ph 2PCH 2PPhPin2 ligand, gives only a 15% yield of the analogous trimetal μ 3-vinylidene hexacarbonyl product CpMnFePt( μ 3-C = CHPh)(CO)(dppm), but the major product (40%) is the tetranuclear μ 4-vinylidene cluster (dppm)PtFe 3( μ 4-C = CHPh)(CO) 9. The IR and 1H, 13C and 31P NMR data for the new complexes are reported and discussed.