The reactivity of molybdenum pentachloride with ethers: routes to the synthesis of MoIVCl4 adducts, Mo(v) chlorido-alkoxides and Mo(v) oxydo-chlorides

Abstract

The reactivity of molybdenum pentachloride, 1, with a selection of mono- and diethers was investigated at room temperature in a non-coordinating solvent (dichloromethane). The Mo(IV) complex MoCl₄(OMe₂)₂, 2, was obtained in 75% yield by the reaction of 1 with an excess of Me₂O; similarly, MoCl₄(κ²-L) [L = EtOCH₂CH₂OEt, 6a; MeOCH₂CH(Me)OMe, 6b] were prepared in good yields by 1 : 1 combination of 1 with the appropriate diether. MoCl₅ reacted with OMePh and Et₂O affording variable amounts of RCl (R = Me and Et, respectively); MoCl₃(OPh)₂, 3, was isolated in 60% yield from 1 and OMePh. The reactions of 1 with OMe^tBu, O^tBu(CHCH₂), MeOCH₂CH₂OCH₂Cl and 1,3-dioxane proceeded with non-selective activation of the organic material. The oxido-complexes Mo₂O₂Cl₄(μ-OMe)₂(μ-MeOH), 4, and MoOCl₃(MeOH)₂, 5, were isolated in modest amounts from 1/OMe^tBu, whereas MoOCl₃(κ²-MeOCH₂CH₂OCH₂Cl), 7, was obtained in 32% yield from 1/MeOCH₂CH₂OCH₂Cl. All of the isolated metal products were characterized by spectroscopic and analytical techniques, and by X-ray diffractometry in the cases of 2, 4, 5, 6b and 7. NMR/GC-MS analyses were carried out in order to outline the fragmentation pathways of the organic reactants.