Photoinduced insertion of tungsten into aromatic and aliphatic carbon–hydrogen bonds by bis(η-cyclopentadienyl)tungsten derivatives

Abstract

Photolysis of solutions of [W(η-C₅H₅)₂H₂] in fluorobenzene, o-xylene, anisole, p-chlorotoluene, p-xylene, mesitylene, p-methylanisole, and methyl benzoate gives the compounds [W(η-C₅H₅)₂H(C₆H₄F-3 and -4)], [W(η-C₅H₅)_2H(C₆H₃Me₂-3,4)], [W(η-C₅H₅)₂H(C₆H₄OMe-4)], [W(η-C₅H₅)₂Cl(C₆H₄Me-4)], [W(η-C₅H₅)₂(CH₂C₆H₄Me-4)₂], [W(η-C₅H₅)₂(CH₂C₆H₃Me₂-3,5)₂], [W(η-C₅H₅)₂(CH₂C₆H₄OMe-4)₂], and [W(η-C₅H₅)₂H(C₆H₄CO₂Me-3 and -4)] together with [W(η-C₅H₅)₂H(OCOPh)], respectively. Thermal decomposition of [W(η-C₅H₅)₂H(Me)] in mesitylene gives [W(η-C₅H₅)₂H(CH₂C₆H₃Me₂-3,5)]. Photolysis of this compound in p-xylene gives [W(η-C₅H₅)₂(CH₂C₆H₄Me-4)(CH₂C₆H₃Me₂-3,5)]. Photolysis of [W(η-C₅H₅)₂H₂] in tetra-methylsilane gives cis- and trans-[H(η-C₅H₅)W(σ: η⁵-C₅H₄)₂W(η-C₅H₅)(CH₂SiMe₃)]. The photoinduced reaction between [W(η-C₅H₅)₂H₂] and toluene, a toluene–mesitylene mixture, and methyl propionate are also described. The mechanisms of these photoinduced insertions of tungsten into aromatic and aliphatic C–H bonds are discussed.