Studies on cyclic bis(η5 : σ-2-cyclopentadienylidene-ethyl)- and bis(η5 : σ-4-cyclopentadienylidenebutyl)-molybdenum compounds

Abstract

Co-condensation of molybdenum atoms with spiro[4.4] nona-1,3-diene gives the compound [Mo{η⁵ : σ-C₅H₄(CH₂)₃CH₂}₂](1). Protonation of (1) causes the cleavage of only one Mo–C bond and following a β-elimination reaction a mixture of exo- and endo-[Mo(η⁵-C₅H₄Buⁿ)(η⁵ : η²-C₅H₄CH₂CH₂CHCH₂)H]PF₆(2) is formed. Treatment of (2) with NaOH gives [Mo(η⁵-C⁵H⁴Buⁿ)(η⁵ : η²-C₅H₄CH₂CH₂CHCH₂)](3). Compound (1) with iodine gives [Mo(η⁵-C₅H₄Buⁿ)(η⁵-C₅H₄CH₂CH₂CHCH₂)I₂](4). Treatment of [Mo(η⁵ : σ-C₅H₄CH₂CH₂)₂] with benzoic acid forms [Mo(η⁵-C⁵H⁴Et)(η⁵σ-C₅H₄CH₂CH₂)(O₂CPh)](5), which with SiMe₃Cl forms [Mo(η⁵-C₅H₄Et)₂Cl₂](6) and [Mo(η⁵-C₅H₄Et)(η⁵ : σ-C₅H₄CH₂CH₂)Cl](7). Compound (7) reacts with PMe₂Ph giving the cation [Mo(η⁵-C₅H₄Et)(η⁵ : σ-C₅H₄CH₂CH₂)(PMe₂Ph)]⁺(8).