Mono(η-cyclopentadienyl)molybdenum chemistry: acetylene, tertiary phosphine, and related derivatives

Abstract

Displacement of chloride in [Mo(η-C₅H₅)(η-C₆H₆)Cl] gives [Mo(η-C₅H₅)(η-C₆H₆)L][PF₆], [L = PPh₃, PMe₂Ph, CO, C₂H₄, C₂H₂, or C₂(CO₂Me)₂] or [Mo(η-C₅H₅)(η-C₆H₆)X](X = H or Me). Loss of benzene gives rise to [Mo(η-C₅H₅)(dppe)₂][PF₆], [Mo(η-C₅H₅)Cl(O)₂], [Mo(η-C₅H₅)Cl₂O], and [Mo(η-C₅H₅)(η-C₈H₈)][PF₆]. Replacement of dppe in [Mo(η-C₅H₅)(dppe)₂][PF₆](or [BF₄]) leads to the salts [Mo(η-C₅H₅)(dppe)L₂][PF₆], [L₂=(CO)(NCMe), (CO)₂, η⁴-C₆H₈, C₄H₆, C₂Me_2· or C₂Ph₂]. Oxidation of [Mo(η-C₅H₅)(dppe)₂][BF₄] by iodine gives paramagnetic [Mo(η-C₅H₅)(dppe)₂][PF₆]₂. The compound [Mo(η-C₅H₅)(η-C₈H₈)][PF₆] reacts with L = CO or PPh₃ giving [Mo(η-C₅H₅)(η-C₈H₈)L][PF₆] and with Ph₂P[CH₂]₂PPh₂(dppe) giving [Mo(η-C₅H₅)(η⁴-C₈H₈)-(dppe)][PF₆]. The compound [Mo(η-C₅H₅)(η⁴-C₄H₆)(dppe)][PF₆] exists in solutions as a mixture of isomers. These react with Na[Al H₂(OCH₂CH₂OMe)₂] giving a separable mixture of the η³-3-methylally compounds [Mo-(η-C₅H₅)(η³-MeCHCHCH₂)(dppe)] where the allyllc group is oriented ‘up’ or ‘down’ relative to the η-C₅H₅ ring.