Preparations and reactions of bis(η-cyclopentadienyl) compounds of molybdenum or tungsten containing covalent bonds to magnesium

TLDR: In this article, the Grignard reagents MgRX (RX = Mel, Pri, or PhBr) were used to give tungsten-magnesium compounds which appear to be generally similar to the molybdenum adducts.

Abstract: The dihydride [Mo(η-C5H5)2H2] reacts with bromo(cyclohexyl)magnesium to give the cyclic dimer [H(η-H5C5)2-Mo{µ-( H11C6)MgBr2Mg(OEt2)}2Mo(η-C5H5)2H], (III). The Grignard reagents MgRX (RX = PriBr, BunBr, Mel, or PhBr) give generally similar products. Derivative (III) reacts with carbon dioxide, carbon monoxide, benzyl bromide, or butadiene to give the compounds [Mo(η-C5H5)2(CO)], [Mo(η5-C5H5)(η3-C5H7)(CO)2], [Mo(η-C5H5)2(CH2Ph)2], and [Mo(η3-C4H7)(η-C5H5)2][PF6] respectively. The isopropyl analogue of (III) reacts similarly. Also, with iodomethane, the compound [MoMe(η-C5H5)2I] is formed. The methyl and phenyl analogues of (III) react with benzyl bromide to give [MoMe(η-C5H5)2(CH2Ph)] and [Mo(η-C5H5)2Ph(CH2Ph)] respectively. The dihvdride [W(η-C5H5)2H2] reacts with the Grignard reagents MgRX (RX = Mel, Pri, or PhBr) to give tungsten–magnesium compounds which appear to be generally similar to the molybdenum adducts.